Tall el-Hammam

Tall el-Hammam

Tall el-Hammam

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Names

Transliterated Name	Source	Name
Tall el-Hammam	Arabic	تل الحمّام
Abel-Shittim	Hebrew	אָבֵל הַשִּׁטִּים
Livias

Introduction

from Chat GPT 5.2, 5 February 2026
sources: Tell el-Hammam

Tell el-Hammam (تل الحمام), also spelled Tall al-Hammam, is a large archaeological mound in the eastern part of the lower Jordan Valley, northeast of the Dead Sea and east of the Jordan River. The site occupies a strategic position near the mouth of the Jordan River and controls routes across the fertile plains at the northern end of the Dead Sea. The settlement consists of a high central mound and an extensive lower town covering roughly 36 hectares. Occupation began in the Late Chalcolithic period and continued through the Bronze and Iron Ages into the Hellenistic, Roman, Byzantine, and Umayyad periods, making it one of the major long-lived sites in the southern Jordan Valley. Tell el-Hammam reached its greatest extent during the Middle Bronze Age, when substantial fortifications were constructed around both the upper and lower parts of the city. The size and defensive works suggest that it functioned as an important regional center controlling agricultural land and trade routes along the Jordan Valley. Because of its scale and location, the site has been linked by some scholars to cities mentioned in ancient texts, although such identifications remain debated. Modern excavations have focused on the Bronze Age fortifications, later occupation phases, and the site’s long and complex occupational history in the Dead Sea region.

Maps, Aerial Views, Plans, Illustrations, Radiocarbon Dates, Photos, and Directionality Images

Maps

Normal Size

Fig. 1.2 Location Map

Fig. 1.2

Map showing Tall al-Hammam and sites with strata contemporaneous with the Occupational levels at Tall al-Hammam. (Courtesy of D.Parker and A.D. Riddle)

Collins et al. (2015)

from Collins et al. (2015)
Fig. 5.5 Location Map

Fig. 5.5

EBA, IBA, and MBA sites on the E Jordan Disk, S Jordan Valley

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 1 Location Map

Fig. 1

Significant sites near Tall el-Hammam

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Silvia (2015)

from Silvia (2015)

Magnified

Fig. 1.2 Location Map

Fig. 1.2

Map showing Tall al-Hammam and sites with strata contemporaneous with the Occupational levels at Tall al-Hammam. (Courtesy of D.Parker and A.D. Riddle)

Collins et al. (2015)

from Collins et al. (2015)
Fig. 5.5 Location Map

Fig. 5.5

EBA, IBA, and MBA sites on the E Jordan Disk, S Jordan Valley

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 1 Location Map

Fig. 1

Significant sites near Tall el-Hammam

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Silvia (2015)

from Silvia (2015)

Aerial Views

Tall el-Hammam in Google Earth

Tall el-Hammam

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Plans

Site Plans

Normal Size

Fig. 1.7 Tell al-Hammam's

Fig. 1.7

A portion of Tell al-Hammam's Grid System

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Collins et al. (2015)

Grid System from Collins et al. (2015)
Fig. 7.2 Site Plan from

Fig. 7.2

Tall al-Hammam in the MBA

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Collins et al. (2015)

Middle Bronze Age from Collins et al. (2015)
Fig. S2 Tall el-Hammam
Fig. S2

Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are
- Field LA = ring road near the main gate for the lower tall
- Field LS = temple complex on the lower tall
- Fields UA, UB, UC = palace complex on the upper tall
The wadi site is not shown

Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html).

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Bunch et al. (2021) Supplemental
showing main excavated areas from Bunch et al. (2021) supplemental
Fig. 4a Map of the city

Fig. 4a

Map of the city (white dashing line) showing sampling locations, spanning ~1100 m

Source of base image: “Tall el-Hammam”. 31° 50.483 N, 35° 40.029 E. Google Earth; CNES/ Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021.

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Bunch et al. (2021)

from Bunch et al. (2021)

Magnified

Fig. 1.7 Tell al-Hammam's

Fig. 1.7

A portion of Tell al-Hammam's Grid System

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Collins et al. (2015)

Grid System from Collins et al. (2015)
Fig. 7.2 Site Plan from

Fig. 7.2

Tall al-Hammam in the MBA

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Collins et al. (2015)

Middle Bronze Age from Collins et al. (2015)
Fig. S2 Tall el-Hammam
Fig. S2

Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are
- Field LA = ring road near the main gate for the lower tall
- Field LS = temple complex on the lower tall
- Fields UA, UB, UC = palace complex on the upper tall
The wadi site is not shown

Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html).

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Bunch et al. (2021) Supplemental
showing main excavated areas from Bunch et al. (2021) supplemental
Fig. 4a Map of the city

Fig. 4a

Map of the city (white dashing line) showing sampling locations, spanning ~1100 m

Source of base image: “Tall el-Hammam”. 31° 50.483 N, 35° 40.029 E. Google Earth; CNES/ Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021.

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Bunch et al. (2021)

from Bunch et al. (2021)

Area Plans

Early Bronze 2-3 City Wall and Gate

Normal Size

Fig. 5.10 EB2-3 wall, gate,

Fig. 5.10

EB2-3 wall, gate, and street

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Collins et al. (2015)

and street from Collins et al. (2015)
Fig. 5.11 Isometric drawing

Fig. 5.11

Isometric drawing of EB2-3 gate

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Collins et al. (2015)

of EB2-3 gate from Collins et al. (2015)
Fig. 5.12 Reconstruction

Fig. 5.12

Reconstruction drawing of EB2-3 gateway

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Collins et al. (2015)

drawing of EB2-3 gateway from Collins et al. (2015)

Magnified

Fig. 5.10 EB2-3 wall, gate,

Fig. 5.10

EB2-3 wall, gate, and street

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Collins et al. (2015)

and street from Collins et al. (2015)
Fig. 5.11 Isometric drawing

Fig. 5.11

Isometric drawing of EB2-3 gate

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Collins et al. (2015)

of EB2-3 gate from Collins et al. (2015)
Fig. 5.12 Reconstruction

Fig. 5.12

Reconstruction drawing of EB2-3 gateway

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Collins et al. (2015)

drawing of EB2-3 gateway from Collins et al. (2015)

Field LA

Normal Size

Fig. 7.4 Field LA plan

Fig. 7.4

Tall al-Hammam-domestic architecture on the Lower Tall.

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 7.6 Field LA fortifications

Fig. 7.6

Hammam’s Lower Tall MBA fortifications(in yellow).

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Collins et al. (2015)

and surrounding area from Collins et al. (2015)
Fig. 20 Aerial View of

Fig. 20

Looking SW across the LA Trench

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Silvia (2015)

LA trench from Silvia (2015)
Trench LA.28 Annotated
Features visible in Trench LA.28 toward the end of Season Seven (2012)
1. EB3 city wall
2. EB3 gateway blocked during the IBA
3. MBA city wall
4. exterior left tower of the MBA gateway complex
5. entryway through the MBA city wall into the left tower
6. domestic area
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Collins & Scott (2016)
from Collins & Scott (2016)

Magnified

Fig. 7.4 Field LA plan

Fig. 7.4

Tall al-Hammam-domestic architecture on the Lower Tall.

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 7.6 Field LA fortifications

Fig. 7.6

Hammam’s Lower Tall MBA fortifications(in yellow).

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Collins et al. (2015)

and surrounding area from Collins et al. (2015)
Fig. 20 Aerial View of

Fig. 20

Looking SW across the LA Trench

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Silvia (2015)

LA trench from Silvia (2015)
Trench LA.28 Annotated
Features visible in Trench LA.28 toward the end of Season Seven (2012)
1. EB3 city wall
2. EB3 gateway blocked during the IBA
3. MBA city wall
4. exterior left tower of the MBA gateway complex
5. entryway through the MBA city wall into the left tower
6. domestic area
Click on image to open in a new tab

Collins & Scott (2016)
from Collins & Scott (2016)

Illustrations

Normal Size

Fig. 5.2 Reconstruction

Fig. 5.2

Reconstruction of Tall al-Hammam in Early Bronze 2-3.

Collins et al. (2015)

of Tall al-Hammam in Early Bronze 2-3 from Collins et al. (2015)

Magnified

Fig. 5.2 Reconstruction

Fig. 5.2

Reconstruction of Tall al-Hammam in Early Bronze 2-3.

Collins et al. (2015)

of Tall al-Hammam in Early Bronze 2-3 from Collins et al. (2015)

Radiocarbon Dates

Normal Size

Fig. 5 Bayesian analysis

Fig. 5

Bayesian analysis. Using OxCal v.4.4.418–20, the ‘Combine’ computer routine determined that 20 of 26 14C dates are statistically synchronous and likely represent a single event at 1661 ± 21 BCE (1686–1632 BCE), rounded to 1650 BCE. Light gray curves represent unmodeled calibrated ages; dark gray represents modeled calibrated ages. Te white dot beneath the curves equals the mean age, also represented by the red dotted vertical line. Progressively longer brackets beneath curves represent 68% and 94% confidece intervals. Te program performed two statistical probability tests to test the robustness of the model. Both the A comb and Chi Sq statistical tests show a high probability, indicating that the modeled age of 1661 ± 21 BCE is likely to be accurate.

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Bunch et al. (2021)

of Middle Bronze Age Destruction radiocarbon dates from Bunch et al. (2021)
Fig. 50 Comparison of Dates

Fig. 50

Comparison of Dates of MBA Destruction of Jericho and Tell el-Hamman. Bayesian calculation showing essentially identical age ranges at 68% Confidece Interval for the destruction layers of the two cities. For Tell el-Hamman, the range is 1686–1632 BCE (1661 ± 21 BCE) and for Jericho 1670–1626 years BCE (1653 ± 18 BCE), for a common overlap of 38 years, making them statistically coeval.

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Bunch et al. (2021)

of Middle Bronze Age Destruction of Jericho and Tell el-Hamman from Bunch et al. (2021)

Magnified

Fig. 5 Bayesian analysis

Fig. 5

Bayesian analysis. Using OxCal v.4.4.418–20, the ‘Combine’ computer routine determined that 20 of 26 14C dates are statistically synchronous and likely represent a single event at 1661 ± 21 BCE (1686–1632 BCE), rounded to 1650 BCE. Light gray curves represent unmodeled calibrated ages; dark gray represents modeled calibrated ages. Te white dot beneath the curves equals the mean age, also represented by the red dotted vertical line. Progressively longer brackets beneath curves represent 68% and 94% confidece intervals. Te program performed two statistical probability tests to test the robustness of the model. Both the A comb and Chi Sq statistical tests show a high probability, indicating that the modeled age of 1661 ± 21 BCE is likely to be accurate.

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Bunch et al. (2021)

of Middle Bronze Age Destruction radiocarbon dates from Bunch et al. (2021)
Fig. 50 Comparison of Dates

Fig. 50

Comparison of Dates of MBA Destruction of Jericho and Tell el-Hamman. Bayesian calculation showing essentially identical age ranges at 68% Confidece Interval for the destruction layers of the two cities. For Tell el-Hamman, the range is 1686–1632 BCE (1661 ± 21 BCE) and for Jericho 1670–1626 years BCE (1653 ± 18 BCE), for a common overlap of 38 years, making them statistically coeval.

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Bunch et al. (2021)

of Middle Bronze Age Destruction of Jericho and Tell el-Hamman from Bunch et al. (2021)

Photos

Normal Size

Fig. 5.8 Earthquake activity

Fig. 5.8

Earthquake activity of EB2 and EB3 rebuild of city wall at Tall al-Hammam

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Collins et al. (2015)

of EB2 and EB3 rebuild of city wall from Collins et al. (2015)
Fig. 5.9 One of Tall al-Hammam’s

Fig. 5.9

One of Tall al-Hammam’s EB2-3 gates

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Collins et al. (2015)

EB2-3 gates from Collins et al. (2015)
Fig. 2.5 LA Trench (Field LA)

Fig. 2.5

Panoramic View of the Tall al-Hammam Excavations, LA Trench (Field LA).

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 2.8 Field LA from

Fig. 2.8

Horizontal Method at Tall al-Hammam, Field LA

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 7.12 MB2 destruction

Fig. 7.12

MB2 destruction layer on the Upper Tall, Field UB.

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Collins et al. (2015)

layer on the Upper Tall, Field UB from Collins et al. (2015)
Fig. 7.13 Terminal MBA

Fig. 7.13

Terminal MBA destruction layer on the Lower Tall

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Collins et al. (2015)

destruction layer on the Lower Tall from Collins et al. (2015)
Fig. 2 Catastrophic leveling
Fig. 2

Catastrophic leveling of the palace at Tall al-Hammam

Artist’s evidence-based reconstruction of the 4-to-5-story palace that was ~ 52 m long and 27 m wide before its destruction

Artist’s evidence-based reconstruction of palace site on upper tall, along with modern excavation. “MB II” marks the top of 1650-BCE Middle Bronze rubble. Note that the fild around the excavation is essentially fat, unlike the view in panel ‘a’. Originally, parts of the 4-story palace were ~ 12 + m tall, but aferward, only a few courses of mudbricks remain on stone foundations, labeled as “wall remnants”. Part of the foundation of the massive wall around the palace is at the bottom. Debris from between sheared walls has been removed by excavation. A comparison of panel ‘a’ to panel ‘b’ shows that millions of mudbricks from the upper parts of the palace and other buildings are missing.

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Bunch et al. (2021)
of the palace at Tall al-Hammam from Bunch et al. (2021)
Fig. 3 Destruction of the
Fig. 3

Destruction of the multi-storied palace. Photo showing jumbled rubble of four-story Palace atop Floor 1. Remains of debris from upper stories are labeled as follows.

#1 represents broken mudbricks and debris from shattered upper walls

#2 and #3 are voids and layers formed when trapped textiles (rugs and tapestries) burned, leaving only fbrous ash and carbon

‘Blow-over’ (in blue) is composed of windblown, laminated deposits that sealed the ruined structure for ~ 3600 years, beginning at the time of destruction.

#4 marks fragments of white limestone plaster (CaCO₃) mixed with carbonate spherules from the palace walls and ceiling.

Scale stick has 10-cm markings.

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Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 4 Sampling locations
Fig. 4

Sedimentary profles

Map of the city (white dashing line) showing sampling locations, spanning ~ 1100 m. Source of base image: “Tall el-Hammam”. 31° 50.483 N, 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021

The wadi

the ring road in Field LA

the palace in Field LS

the palace in Field UA

In the wadi, yellow arrows mark the level of the 3600-year-old stratum. Inside the city, the arrows mark the location of the charcoal-and-ash-rich dark layer.

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Bunch et al. (2021)
from Bunch et al. (2021)
Fig. 6 Multiple burned layers

Fig. 6

Multiple burned layers at Tall el-Hammam. On the upper tall, there are three terminal burn layers: one during the Middle Bronze Age (MB II), another during Late Bronze Age II (LBA), and one higher during the Iron Age (not visible here). Each burn layer represents the end of an archaeological period at the site. Dashed white line encloses LBA burn layer at arrow, representing the burning of a single building at ~ 1400 BCE stacked atop the sheared MB-II walls. “MBA flor” marks the top of the MB II flor beneath the 1.5-m-thick destruction layer dating to 1650 BCE. Two earthquake-related destruction layers (not shown) are buried deeper than the flor of this excavation, one dated ~ 400 years earlier at ~ 2100 BCE and the other even older at ~ 3300 BCE. All these layers are distinctly separate from the MB II destruction layer above bottom arrow, the only layer that contains high-temperature melted materials.

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Bunch et al. (2021)

on Upper Tall in Middle Bronze Age from Bunch et al. (2021)
Fig. 7 Destruction layer in
Fig. 7

Destruction layer in the palace

Photo of excavation in an exterior food preparation area of the palace. #1 marks MB II debris that was most likely deposited by post-fie erosion. #2 points to charcoal-rich ‘dark layer’ indicating a major fie in the palace. Contains fragments of plaster and limestone spherules. Blue arrows mark its top. #3 points to the cross-section of excavated clay floring

Close-up photo of the same palace sampling sequence as in panel ‘a’

Photo of broken pots with carbonized grains embedded in MB II 1.5-m-thick debris matrix, mostly composed of pulverized mudbrick and plaster fragments and limestone spherules. Debris matrix is found in the space between all palace walls. Note charcoal inside the broken pot. Te end of a scale stick with 10-cm divisions is at upper left

Charred palace roof timber surrounded by 1.5-m-thick charcoal-rich debris matrix of pulverized mudbrick. A scale stick shows 10-cm markings

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Bunch et al. (2021)
the palace from Bunch et al. (2021)
Fig. 17 Directionality of

Fig. 17

The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide).

Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html).

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Bunch et al. (2021)

debris across the entire Tall el-Hammam site from Bunch et al. (2021)
Fig. 44 Human bones in the
Fig. 44

Human bones in the destruction layer

Photo of a disarticulated skull found near the palace on the ring road around the upper tall. The right eye socket has been crushed (orange arrow). Skull is embedded in pulverized mudbrick containing numerous charcoal fragments (yellow circles) and is stained with ash commonly found in the destruction layer (blue arrow). Te orange tint of the skull suggests it was exposed to temperatures > 200 °C141

Rear view of the same skull in panel ‘a’ (blue arrow) near the second skull (purple arrow) and numerous disarticulated, fragmented human bones (orange arrows). Charcoal fragments at yellow circles

Lower torso from the ring road of lower tall (orange arrows), and other disarticulated bones. Bones show evidence of being burned (red arrows); the rest of the skeleton is dismembered and disarticulated. Hyper-fleed toes (purple arrow) are consistent with either perimortem or postmortem exposure to high temperatures

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Bunch et al. (2021)
destruction layer site from Bunch et al. (2021)
Fig. 20 Aerial View of

Fig. 20

Looking SW across the LA Trench

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Silvia (2015)

LA trench from Silvia (2015)
Fig. 22 LBA and MBA destruction

Fig. 22

LBA and MBA destruction layers in Square UA.7GG on Upper Tall el-Hammam

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Silvia (2015)

layers in Square UA.7GG on Upper Tall el-Hammam from Silvia (2015)
The “Late Bronze Age Gap”

The “Late Bronze Age Gap” at Tall el-Hammam is dramatically demonstrated in this trench on the upper tall. Here you can see the Iron Age 2 city wall (A) built directly on top of the Middle Bronze Age mudbrick defensive rampart (B) that surrounds the upper city. There is a seven-century time gap between the two structures. The same gap is evident over the entire site, indeed over the entire eastern Kikkar of the Jordan.

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Collins & Scott (2016)

at Tall el-Hammam from Collins & Scott (2016)
Human bone (HB) scatter

Human bone (HB) scatter in the ashy matrix of Hammam’s MB2 destruction

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Collins & Scott (2016)

in the ashy matrix of Hammam’s MB2 destruction from Collins & Scott (2016)
Trench LA.28 Annotated
Features visible in Trench LA.28 toward the end of Season Seven (2012)
1. EB3 city wall
2. EB3 gateway blocked during the IBA
3. MBA city wall
4. exterior left tower of the MBA gateway complex
5. entryway through the MBA city wall into the left tower
6. domestic area
Click on image to open in a new tab

Collins & Scott (2016)
from Collins & Scott (2016)
Fig. S1 Collapsed multi-storied

Fig. S1

Collapsed multi-storied palace. Photo showing jumbled remains of three stories of the palace; the fourth story is completely missing. #1 represents a circular clay MBA oven called a tabun. #2 is a broken potsherd. #3 represents broken and burned mudbricks from the upper walls. #4 represents sections of burned roofing and upper-story flooring material. #5 represents charred wood from upper stories. The ‘blow-over’ layer capped and sealed the destroyed palace, which lay undisturbed for ~600 years. One-meter scale stick shown with 10-cm markings.

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Bunch et al. (2021) Supplemental

palace (Middle Bronze II Destruction) from Bunch et al. (2021) supplemental
Excavations on the Acropolis

Excavations on the Acropolis

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Photo by Jefferson Williams - 29 Jan. 2026

- photo by JW
Excavations on the Acropolis

Excavations on the Acropolis

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Photo by Jefferson Williams - 29 Jan. 2026

- photo by JW

Magnified

Fig. 5.8 Earthquake activity

Fig. 5.8

Earthquake activity of EB2 and EB3 rebuild of city wall at Tall al-Hammam

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Collins et al. (2015)

of EB2 and EB3 rebuild of city wall from Collins et al. (2015)
Fig. 5.9 One of Tall al-Hammam’s

Fig. 5.9

One of Tall al-Hammam’s EB2-3 gates

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Collins et al. (2015)

EB2-3 gates from Collins et al. (2015)
Fig. 2.5 LA Trench (Field LA)

Fig. 2.5

Panoramic View of the Tall al-Hammam Excavations, LA Trench (Field LA).

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 2.8 Field LA from

Fig. 2.8

Horizontal Method at Tall al-Hammam, Field LA

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Collins et al. (2015)

from Collins et al. (2015)
Fig. 7.12 MB2 destruction

Fig. 7.12

MB2 destruction layer on the Upper Tall, Field UB.

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Collins et al. (2015)

layer on the Upper Tall, Field UB from Collins et al. (2015)
Fig. 7.13 Terminal MBA

Fig. 7.13

Terminal MBA destruction layer on the Lower Tall

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Collins et al. (2015)

destruction layer on the Lower Tall from Collins et al. (2015)
Fig. 2 Catastrophic leveling
Fig. 2

Catastrophic leveling of the palace at Tall al-Hammam

Artist’s evidence-based reconstruction of the 4-to-5-story palace that was ~ 52 m long and 27 m wide before its destruction

Artist’s evidence-based reconstruction of palace site on upper tall, along with modern excavation. “MB II” marks the top of 1650-BCE Middle Bronze rubble. Note that the fild around the excavation is essentially fat, unlike the view in panel ‘a’. Originally, parts of the 4-story palace were ~ 12 + m tall, but aferward, only a few courses of mudbricks remain on stone foundations, labeled as “wall remnants”. Part of the foundation of the massive wall around the palace is at the bottom. Debris from between sheared walls has been removed by excavation. A comparison of panel ‘a’ to panel ‘b’ shows that millions of mudbricks from the upper parts of the palace and other buildings are missing.

Click on image to open in a new tab

Bunch et al. (2021)
of the palace at Tall al-Hammam from Bunch et al. (2021)
Fig. 3 Destruction of the
Fig. 3

Destruction of the multi-storied palace. Photo showing jumbled rubble of four-story Palace atop Floor 1. Remains of debris from upper stories are labeled as follows.

#1 represents broken mudbricks and debris from shattered upper walls

#2 and #3 are voids and layers formed when trapped textiles (rugs and tapestries) burned, leaving only fbrous ash and carbon

‘Blow-over’ (in blue) is composed of windblown, laminated deposits that sealed the ruined structure for ~ 3600 years, beginning at the time of destruction.

#4 marks fragments of white limestone plaster (CaCO₃) mixed with carbonate spherules from the palace walls and ceiling.

Scale stick has 10-cm markings.

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 4 Sampling locations
Fig. 4

Sedimentary profles

Map of the city (white dashing line) showing sampling locations, spanning ~ 1100 m. Source of base image: “Tall el-Hammam”. 31° 50.483 N, 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021

The wadi

the ring road in Field LA

the palace in Field LS

the palace in Field UA

In the wadi, yellow arrows mark the level of the 3600-year-old stratum. Inside the city, the arrows mark the location of the charcoal-and-ash-rich dark layer.

Click on image to open in a new tab

Bunch et al. (2021)
from Bunch et al. (2021)
Fig. 6 Multiple burned layers

Fig. 6

Multiple burned layers at Tall el-Hammam. On the upper tall, there are three terminal burn layers: one during the Middle Bronze Age (MB II), another during Late Bronze Age II (LBA), and one higher during the Iron Age (not visible here). Each burn layer represents the end of an archaeological period at the site. Dashed white line encloses LBA burn layer at arrow, representing the burning of a single building at ~ 1400 BCE stacked atop the sheared MB-II walls. “MBA flor” marks the top of the MB II flor beneath the 1.5-m-thick destruction layer dating to 1650 BCE. Two earthquake-related destruction layers (not shown) are buried deeper than the flor of this excavation, one dated ~ 400 years earlier at ~ 2100 BCE and the other even older at ~ 3300 BCE. All these layers are distinctly separate from the MB II destruction layer above bottom arrow, the only layer that contains high-temperature melted materials.

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Bunch et al. (2021)

on Upper Tall in Middle Bronze Age from Bunch et al. (2021)
Fig. 7 Destruction layer in
Fig. 7

Destruction layer in the palace

Photo of excavation in an exterior food preparation area of the palace. #1 marks MB II debris that was most likely deposited by post-fie erosion. #2 points to charcoal-rich ‘dark layer’ indicating a major fie in the palace. Contains fragments of plaster and limestone spherules. Blue arrows mark its top. #3 points to the cross-section of excavated clay floring

Close-up photo of the same palace sampling sequence as in panel ‘a’

Photo of broken pots with carbonized grains embedded in MB II 1.5-m-thick debris matrix, mostly composed of pulverized mudbrick and plaster fragments and limestone spherules. Debris matrix is found in the space between all palace walls. Note charcoal inside the broken pot. Te end of a scale stick with 10-cm divisions is at upper left

Charred palace roof timber surrounded by 1.5-m-thick charcoal-rich debris matrix of pulverized mudbrick. A scale stick shows 10-cm markings

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Bunch et al. (2021)
the palace from Bunch et al. (2021)
Fig. 17 Directionality of

Fig. 17

The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide).

Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html).

Click on image to open in a new tab

Bunch et al. (2021)

debris across the entire Tall el-Hammam site from Bunch et al. (2021)
Fig. 44 Human bones in the
Fig. 44

Human bones in the destruction layer

Photo of a disarticulated skull found near the palace on the ring road around the upper tall. The right eye socket has been crushed (orange arrow). Skull is embedded in pulverized mudbrick containing numerous charcoal fragments (yellow circles) and is stained with ash commonly found in the destruction layer (blue arrow). Te orange tint of the skull suggests it was exposed to temperatures > 200 °C141

Rear view of the same skull in panel ‘a’ (blue arrow) near the second skull (purple arrow) and numerous disarticulated, fragmented human bones (orange arrows). Charcoal fragments at yellow circles

Lower torso from the ring road of lower tall (orange arrows), and other disarticulated bones. Bones show evidence of being burned (red arrows); the rest of the skeleton is dismembered and disarticulated. Hyper-fleed toes (purple arrow) are consistent with either perimortem or postmortem exposure to high temperatures

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Bunch et al. (2021)
destruction layer site from Bunch et al. (2021)
Fig. 20 Aerial View of

Fig. 20

Looking SW across the LA Trench

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Silvia (2015)

LA trench from Silvia (2015)
Fig. 22 LBA and MBA destruction

Fig. 22

LBA and MBA destruction layers in Square UA.7GG on Upper Tall el-Hammam

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Silvia (2015)

layers in Square UA.7GG on Upper Tall el-Hammam from Silvia (2015)
The “Late Bronze Age Gap”

The “Late Bronze Age Gap” at Tall el-Hammam is dramatically demonstrated in this trench on the upper tall. Here you can see the Iron Age 2 city wall (A) built directly on top of the Middle Bronze Age mudbrick defensive rampart (B) that surrounds the upper city. There is a seven-century time gap between the two structures. The same gap is evident over the entire site, indeed over the entire eastern Kikkar of the Jordan.

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Collins & Scott (2016)

at Tall el-Hammam from Collins & Scott (2016)
Trench LA.28 Annotated
Features visible in Trench LA.28 toward the end of Season Seven (2012)
1. EB3 city wall
2. EB3 gateway blocked during the IBA
3. MBA city wall
4. exterior left tower of the MBA gateway complex
5. entryway through the MBA city wall into the left tower
6. domestic area
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Collins & Scott (2016)
from Collins & Scott (2016)
Human bone (HB) scatter

Human bone (HB) scatter in the ashy matrix of Hammam’s MB2 destruction

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Collins & Scott (2016)

in the ashy matrix of Hammam’s MB2 destruction from Collins & Scott (2016)
Fig. S1 Collapsed multi-storied

Fig. S1

Collapsed multi-storied palace. Photo showing jumbled remains of three stories of the palace; the fourth story is completely missing. #1 represents a circular clay MBA oven called a tabun. #2 is a broken potsherd. #3 represents broken and burned mudbricks from the upper walls. #4 represents sections of burned roofing and upper-story flooring material. #5 represents charred wood from upper stories. The ‘blow-over’ layer capped and sealed the destroyed palace, which lay undisturbed for ~600 years. One-meter scale stick shown with 10-cm markings.

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Bunch et al. (2021) Supplemental

palace (Middle Bronze II Destruction) from Bunch et al. (2021) supplemental
Excavations on the Acropolis

Excavations on the Acropolis

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Photo by Jefferson Williams - 29 Jan. 2026

- photo by JW
Excavations on the Acropolis

Excavations on the Acropolis

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Photo by Jefferson Williams - 29 Jan. 2026

- photo by JW

Directionality Images

Normal Size

Fig. 15 Destruction of the
Fig. 15

The directionality of mudbricks, potsherds, and grains

400-kg quern, at left, used for grinding grain, is tipped over with top towards NE. Image view spans~2.5 m. Area #1 shows broken pottery and meltglass piled against quern from SW to NE (arrow). Area #2 contains charcoal, charred grains, ash, and mudbrick fragments, but no potsherds, suggesting that the quern shielded the floor to the NE. The area at the top labeled ‘blow-over’ is evidence that strong winds sealed the deposit with windblown laminated material that includes pulverized mudbrick, charcoal, ash, and fragments of white plaster. The draping of the blowover indicates debris traveled from SW to NE. The scale stick is in 10-cm intervals

Directional potsherds. Blue, red, and green asterisks (*) represent color-coded potsherds from three different pots. Arrows mark the motion of potsherds from SW to NE, spanning ~1 m. Area #1 represents the inverted bottom of the pot with its smaller fragments strewn to the left. Some pots contained charred grains also strewn in a SW-to-NE direction. Radiocarbon dates on charred grains confirm an age of ~1650 BCE (3600 cal BP)

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Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 16 Destruction of the
Fig. 16

High-velocity effects

Photo of an excavated section of the palace wall on upper tall. In the center are the lower courses of the mudbrick wall (#1a, between white dashed lines) and foundation (#1b). Yellow dashed line with arrow indicates wind direction of blow-over to NE. Also, note the lines of white fragments of broken plaster at two blue arrows (#4), where the curved wall top displays intense wind abrasion. At the right side of the image, #6 marks the limit of modern excavation. The sequence of wall destruction is illustrated in panels ‘b’ to ‘e’ below.

An artistic depiction, re-creating the pre-destruction mudbrick wall and foundation highlighted in red (#1)

Rubble in red (#2) was blown against the SW-facing side of the wall; material mainly consists of pulverized mudbricks and shattered potsherds

Section of wall higher than several courses of mudbrick was demolished and blown to the NE to form the debris matrix (#3)

High-velocity winds blew from SW to NE (arrows), severely abrading the top of the wall, and burying it in debris. Winds produced the laminated ‘blow-over’ (#4), containing small pulverized mudbricks, fragments of white wall plaster, and limestone spherules stripped from interior walls. Settling on top, the ‘dark layer’ (#5) is mostly composed of charcoal and ash from the city-wide fires, along with post-destruction fine particulates

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Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 17 Directionality of

Fig. 17

The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide).

Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html).

Click on image to open in a new tab

Bunch et al. (2021)

debris across the entire Tall el-Hammam site from Bunch et al. (2021)

Magnified

Fig. 15 Destruction of the
Fig. 15

The directionality of mudbricks, potsherds, and grains

400-kg quern, at left, used for grinding grain, is tipped over with top towards NE. Image view spans~2.5 m. Area #1 shows broken pottery and meltglass piled against quern from SW to NE (arrow). Area #2 contains charcoal, charred grains, ash, and mudbrick fragments, but no potsherds, suggesting that the quern shielded the floor to the NE. The area at the top labeled ‘blow-over’ is evidence that strong winds sealed the deposit with windblown laminated material that includes pulverized mudbrick, charcoal, ash, and fragments of white plaster. The draping of the blowover indicates debris traveled from SW to NE. The scale stick is in 10-cm intervals

Directional potsherds. Blue, red, and green asterisks (*) represent color-coded potsherds from three different pots. Arrows mark the motion of potsherds from SW to NE, spanning ~1 m. Area #1 represents the inverted bottom of the pot with its smaller fragments strewn to the left. Some pots contained charred grains also strewn in a SW-to-NE direction. Radiocarbon dates on charred grains confirm an age of ~1650 BCE (3600 cal BP)

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 16 Destruction of the
Fig. 16

High-velocity effects

Photo of an excavated section of the palace wall on upper tall. In the center are the lower courses of the mudbrick wall (#1a, between white dashed lines) and foundation (#1b). Yellow dashed line with arrow indicates wind direction of blow-over to NE. Also, note the lines of white fragments of broken plaster at two blue arrows (#4), where the curved wall top displays intense wind abrasion. At the right side of the image, #6 marks the limit of modern excavation. The sequence of wall destruction is illustrated in panels ‘b’ to ‘e’ below.

An artistic depiction, re-creating the pre-destruction mudbrick wall and foundation highlighted in red (#1)

Rubble in red (#2) was blown against the SW-facing side of the wall; material mainly consists of pulverized mudbricks and shattered potsherds

Section of wall higher than several courses of mudbrick was demolished and blown to the NE to form the debris matrix (#3)

High-velocity winds blew from SW to NE (arrows), severely abrading the top of the wall, and burying it in debris. Winds produced the laminated ‘blow-over’ (#4), containing small pulverized mudbricks, fragments of white wall plaster, and limestone spherules stripped from interior walls. Settling on top, the ‘dark layer’ (#5) is mostly composed of charcoal and ash from the city-wide fires, along with post-destruction fine particulates

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 17 Directionality of

Fig. 17

The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide).

Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html).

Click on image to open in a new tab

Bunch et al. (2021)

debris across the entire Tall el-Hammam site from Bunch et al. (2021)

Archaeoseismic Chronology

Stratigraphy

Entire Site

from Collins et al. (2015)

Archaeological Periods and Tall al-Hammam Strata

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Collins et al. (2015)

Chronological Divisions

The Iron Age in the Southern Levant

Bronze Age of the Levant

City Wall Earthquake 1 - Early Bronze II/Early Bronze III Transition - ca. 2700 BCE

Discussion

References

The Tall al-Hammam Excavations, Volume 1 - Collins et al. (2015)

Director's Introduction

Long, Unbroken Occupation

from Collins et al. (2015:xxiii-xxiv)

Second, Tall al-Hammam is remarkable for its settlement history. It was consistently occupied from at least the late Chalcolithic Period through the Middle Bronze Age (Collins et al 2009b, 2011a).³ A careful analysis of site strata reveals a systematic absence of wind-borne or erosional sedimentation between architectural phases. At least two earthquake events—one at the EB2/EB3 transition, one at the IB2/MB1 transition—are detectable across the site (Collins et al 2013). In both cases the city was immediately rebuilt/ refurbished. After its destruction toward the end of MB2 there is a noteworthy gap in occupation which lasted approximately 700 years.⁴ The reason(s) for this long settlement hiatus at Tall al-Hammam— which seems to be mirrored at all sites within a 10km radius of Tall al-Hammam—is still being studied.

Footnotes

3. A few Neolithic artifacts have turned up in ‘fill’ material, but we have not yet excavated deep enough in thes locations to expose what Neolithic remains might still exist.

4. Tall al-Hammam was completely uninhabited between MB2 and the 10th century BCE (IA2). This resulted in significant eosion during this space of time.

Evolution of Complex Fortification System

from Collins et al. (2015:xxvii)

... As it happened, Tall al-Hammam’s initial city wall (EB2) enclosed at least 25 hectares which was, in turn, surrounded by agricultural settlements in close proximity. But that wall was severely damaged— probably by an earthquake—during the transition from EB2 to EB3, ca. 2700 BCE. Excavated sections of the EBA city wall reveal that the EB2 phase had only one or two course-lines of medium to large boulders running parallel to the direction of the wall at the base of the inner and outer faces. Between the outer and inner lines of boulders the 6m-thick EB2 wall consisted of mudbricks only—thus its structural vulnerability. The subsequent EB3 version of the city wall was significantly more substantial, with the installation of an all-stone foundation of small-to-medium boulders, five to six courses laid to the full 6m width. This foundation was topped with a mudbrick superstructure, some sections of which still have 10 to 20 courses in situ. The EB3 city wall continued in use—with some modifications, including the blocking of several gateways—through the IBA (= EB IV; EB4). The dimensions of Tall al-Hammam’s 6m-thick EBA/IBA city wall are close to those of the Tell Mardikh/Ebla EB IV (= IBA) city wall (Matthiae 2013b). The principal gateway remained in the same location throughout the EBA and IBA.

The IBA fortifications were still in use at Tall al-Hammam when a major earthquake devastated the city between 2000 and 1950 BCE, probably damaging the perimeter defenses beyond repair. But no matter—it seems that the city ‘fathers’ had something else in mind all along, and this was the perfect ‘excuse’ to put their plans into motion. What they envisioned was a new style of fortification system that rose to the challenges presented by rapidly evolving methods of siege warfare—siege towers, mobile battering rams, and sapper battalions skilled in the art of breaching city walls (Burke 2008; McAllister 2008). From what source(s) their system designs originated is unclear, but the same general type of ‘ramparted’ fortifications began to be built across both the southern and northern Levant around the beginning of the Middle Bronze Age (MB1), ca. 2000–1950 BCE.

While it has been argued that the various rampart styles (such as freestanding vs. supplemental) and circumferential shapes (such as curvilinear vs. straight) were temporal developments (Burke 2008; Kempinski 1992) from the beginning of MB1 through the waning decades of MB2 (ca. 1600 BCE), what we have learned from the evolution of Tall al-Hammam’s Bronze Age defenses is that the utilization of various types of ramparts is driven more by topographical and substrate considerations than anything else. To a significant degree, this also seems to be true of city wall, tower, bastion, buttress, and gateway construction. For example, along the approximately 800m stretch of Tall al-Hammam’s southern rampart system both freestanding and supplemental styles are incorporated. In locations where the bedrock is already sloping downward and away from a higher, more level substrate upon which the city wall foundation is installed, an exterior supplemental rampart exists. In these instances, the tallest portion of the rampart against the outer face of the city wall was installed over the EBA/IBA city wall, purposefully deconstructed down to .5m to 1m of mudbrick superstructure adhering to a 6m-thick, 5-course boulder foundation. It is obvious that the MBA builders saw their old-but-stable city wall as the perfect footing to bear the vertical load of the new rampart system fabricated almost entirely of mudbricks (with internal stabilizer walls built of stone). With the heaviest portion of the rampart supported by the re-engineered remains of the EBA/IBA city wall, the MBA city wall—itself 4–5m thick on a foundation of medium-to-large boulders—bore none of the vertical weight of the mudbrick supplemental rampart. Interestingly, if a supplemental rampart were constructed merely of packed earth and other ‘loose’ materials, a significant portion of its weight would be transferred against the city wall, increasing the probability of catastrophic failure in an earthquake scenario. The engineering of Tall al-Hammam’s supplemental rampart segments was, therefore, nothing short of brilliant, given its location in the seismically active Rift Valley.

Chapter 5 - Early Bronze Period at Tall al-Hammam (3600-2500 BCE)

Early Bronze 2 Architecture at Tall al-Hammam

from Collins et al. (2015:58-59)

In most cases excavated thus far, EB2 structures at Tall al-Hammam exist as the first phase—foundations and often several mudbrick courses—of what eventually become EB3 refurbishments and reconstruction. Most of the stone foundations of EB2–3 houses originated in EB2. Only periodically can domestic foundations be dated to EB3 and, in such instances, they are usually new extensions onto already existing structures. In other words, Tall al-Hammam’s EB3 occupation transitioned ‘organically’ from EB2, slavishly following wall lines established in the earlier period. There was, however, a disruptive event that seems to have required residents to rebuild most of the architecture across the site at about the transition from EB2 to EB3, ca. 2700 BCE (Collins et al 2011, 2009).

The EB2 to EB3 architectural interface is easily seen in the construction history of Hammam’s massive city wall—from 5.2m to 6m thick—enclosing an area in excess of 25ha (more than 60 acres). At some point toward the end of EB2 or beginning of EB3, a significant earthquake occurred that (seemingly) caused extensive damage over most of the city. (See Figure 5.8.) Evidence of this disruption is clearly visible as post-quake adjustments to the city wall foundation. The original EB2 foundation consisted of one to two rows of large stones set on bedrock along the inner and outer faces, with mudbricks between to the level of the stones. While this stone and mudbrick foundation required less effort than an all-stone approach, it turned out not to be a very good idea. The earthquake did so much damage that virtually the entire city wall had to be rebuilt. The EB2 wall was deconstructed down to what remained stable—which was not much. However, the EB3 builders determined that a few sections of the EB2 foundation remained stable enough to be incorporated into the new construction. Some of the EB2 stone and mudbrick foundation was purposefully left in place, and a massive, all-stone foundation—6m thick and six courses high—was installed. But curiously, in a few places, one or two courses of EB2 mudbricks are visible on the outer face underneath the EB3 all-stone foundation. Evidence of an EB2 direct-entry gateway is still visible in Field LA (Collins et al 2011).

Early Bronze 3 Architecture at Tall al-Hammam

from Collins et al. (2015:71-73)

Tall al-Hammam’s EBA fortifications rival, if not surpass, most sites in both size and sophistication. At over 25ha during EB3, the walled city with its towers and gateways was an imposing sight along the multiple trade routes intersecting in her shadow. (See Figure 5.9.)

Following the ca. 2700 BCE earthquake damage at Tall al-Hammam—similar to the devastation at Khirbet al-Batrawy at about the same time (Nigro 2008)—its city wall was widened slightly to about 6m in order to support a taller mudbrick superstructure built upon a foundation consisting of six courses of medium-to-large fieldstones. Partial remains of the mudbrick city wall—up to a dozen courses in places—remain intact. The stone foundation is preserved in its entirety over most of the length of the southern defenses (due to its integration into the later, and much larger, MBA fortifications) (Collins et al 2011, 2009).

Excavations along the outer face of the EB3 city wall exposed a 1.4m-wide direct-entry gateway (one of many, as it turns out) (Collins et al 2009). This width is consistent with other entryways of the EB3 (Nigro 2008). Large, rectangular towers flank each side of the gate. The two towers provided additional protection for the city at this most vulnerable location. While it is impossible to determine their exact height, TaHEP archaeological architect, L. Ritmeyer, estimates that they were between 8m and 9m high. Based on other sites—cf. Batrawy’s calculation of a 4m mudbrick superstructure, in addition to its stone foundation, and a possible wood and mudbrick coronation—this approximation is entirely reasonable (Nigro 2008:80). The passageway of this particular EB3 gate was subsequently blocked during the IBA, but its three massive threshold stones, as well as the compacted-earth main road leading into the city and inside the gateway have been exposed. (See Figures 5.10., 5.11., and 5.12.)

Another gateway is visible 22m to the east along the city wall. An additional gateway exists 22m to its east, directly underneath the MBA gateway. It is probable that the EB3 gateway underneath the MBA monumental gateway had also been the location of the main entrance of the EB2–3 city, given that the EBA—later to be IBA— fortifications remained in use until they were swallowed up by an enormous MBA defensive system (Collins et al. 2019–2013).

A portion of the EB3 domestic area has been excavated directly inside the city wall near the gateway (Field LA). Apparent in all structures are the tightly knit phases of architectural evolution from EB2 and EB3, ultimately into the IBA and MBA, following the same footprints and wall lines, period to period, which is a clear indication of unbroken occupation. Ash, sometimes in remarkable quantities, is consistent throughout the EB2–3 domestic area (Field LA), further demonstrating the earthquake event that led to the houses being rebuilt. Significant details of domestic life have emerged from Field LA, including in-situ door socket stones and large holemouth jars installed in floors as a means of storage. (Figures 5.13. and 5.14.) An open-air courtyard full of food preparation installations and artifacts has provided evidence of use through multiple periods, beginning in EB3 (Collins et al 2011–2013).

City Wall Earthquake 2 - Intermediate Bronze II/Middle Bronze I Transition - 2000-1950 BCE

Discussion

References

The Tall al-Hammam Excavations, Volume 1 - Collins et al. (2015)

Director's Introduction

Long, Unbroken Occupation

from Collins et al. (2015:xxiii-xxiv)

Footnotes

Evolution of Complex Fortification System

from Collins et al. (2015:xxvii)

Chapter 5 - Early Bronze Period at Tall al-Hammam (3600-2500 BCE)

Early Bronze 2 Architecture at Tall al-Hammam

from Collins et al. (2015:58-59)

Early Bronze 3 Architecture at Tall al-Hammam

from Collins et al. (2015:71-73)

Fiery Destruction - Middle Bronze II - ca. 1650 BCE

Discussion

References

The Tall al-Hammam Excavations, Volume 1 - Collins et al. (2015)

Director's Introduction

Long, Unbroken Occupation

from Collins et al. (2015:xxiii-xxiv)

Footnotes

Chapter 7 - Middle Bronze Age Tall al-Hammam (1950–1550 BCE)

Period Synopsis and Generalization

from Collins et al. (2015:173-175)

The Middle Bronze Age (hereafter, MBA) is known for its dramatic re-urbanization after the decline represented in the previous Intermediate Bronze Age. Many sites that had been deserted at the end of EB3 were now restored, some in comparatively grand fashion. Toward the end of the IBA, the nomadic lifestyle, to which much of the S Levantine population had become accustomed, once again gave way to a more organized, structured society. Most IBA sites experienced re-invigoration and expansion. Others, like Khirbet Iskander, dissipated or died. The previous debate concerning the reality, or nonexistence, of Early Bronze Age city-states has not, for the most part, carried into the discussion of MBA socio-political organization in the S Levant. It is widely recognized that numerous MBA political units were culturally linked to other sites, even neighboring civilizations, especially during MB2. Palaces, trading centers, and temples were the framework of cities, while formidable fortification architecture protected urban interests (Kempinski 1992; Burke 2008). However, the MBA urban resurgence did not occur rapidly, nor was it simultaneous for cities across the Levant.

Unlike the IBA societal disruptions seen in the archaeology of Israel, Palestine, and Jordan, there exists in the coastal plains of Syria and Lebanon ample evidence of cultural continuity between the 3rd and 2nd millennia BCE (Mazar 1990). Therefore, it is a virtual consensus that the Cisjordan MB1 (ca. 1950-1800 BCE) derived its cultural impetus from these more-northern origins (Mazar 1990; Dever 1987). Many sites closest to the N Levantine homelands, principally in northern and coastal Syro-Palestine, transitioned to new ways of life much earlier than their chronological counterparts in the south, or east of the Jordan River. It has been widely accepted that MB1 urbanization and materia culture was not substantially developed in the Jordan Valley until MB2 (Cohen 2009). This is a valuable observation, especially in light of the fact tha Tall al-Hammam was fully functional as an urban center during MB1. Although MB1 Hammam was large city with sophisticated fortifications, its MB1 ceramic tradition was quite resistant to `foreign influences from the N Levant. Its millennium-lon€ run of societal continuity as an urban center seem to have established a sense that certain icons of material culture were `inviolable'. This is clear13 observable in regard to some of Hammam' s MB1 ceramic forms. Certain vessels, especially the holemouth cooking pots, seem almost `iconic' as a traditional means of meal preparation. Although the composition of clay-bodies, rim forms, and wheeling techniques of holemouth cooking pots take on typical MB1 features, the basic form lingers well into the period. By contrast, holemouth forms in coastal and northern areas become extinct at the beginning of MB1 (Hendrix et al 1996; Amiran 1970).

Riding the peak of a long wet period in the always-fluctuating Levantine climatological regime (Falconer 2008), many MB1 settlements coalesced into large fortified towns, then into full-fledged cities, even city-states. Ashkelon on the S Levantine coast and Tall al-Hammam in the S Jordan Valley are prime examples (Kempinski 1992). But the dynamics of this process, region to region, are mysterious and unpredictable. For example, well-positioned and former EBA sites like Jerusalem and Hazor had no occupation during MB1. So, there seems to be no rhyme or reason as to why some locations ascended during MB1 and others rose dramatically at the beginning of MB2, as did Hazor and Jerusalem (Kempinski 1992; Falconer 2008).

At approximately the end of MB1, many settlements experienced intensified growth and agricultural production, some expanding on previously existing occupation, others starting virtually from scratch. By the beginning of MB2 (ca. 1800 BCE), burgeoning populations and more refined trends in urbanization led to sophisticated city planning and the building of complex fortifications. Many cities west of the Jordan River became larger than at any time in history up to that point. Hazor attained an area of 83ha (200 acres; its former EBA settlement was 1 lha) (Kempinski 1992). Ashkelon broke from its previous boundaries to encompass an estimated 62ha.

Hammam' s lower city fortifications, enclosing more than 25ha (60 acres), included a city wall, a massive, exterior defensive rampart system, and a monumental gateway, all constructed at the beginning of MB1 (Collins et al 2009-2013). Within that perimeter, a second defensive rampart system rises to an average of 33m above the Lower Tall, creating an Upper City. We have yet to make a final determination on whether the Upper City rampart was built during MB1 or at the beginning of MB2. We strongly suspect the latter. Either way, Hammam retained the extent of its MB1 footprint into MB2. Using oft-proposed formula that urban areas can accommodate an average of 250 persons per hectare, Tall al-Hammam' s population in the Middle Bronze would have reached 6,250 people. However, S. Collins considers this number should be adjusted higher to accommodate 360 persons per hectare (150 per acre). Thus, Tall al-Ham-mam' s population would have been between 9,000 and 10,000 people given its 25 hectares (Kempin-ski 1992; Broshi, Gophna 1984; cf. Collins 2011). (See Figure 7.1.)

Although many cities were large, with imposing architecture and defenses, the transition from MB1 to MB2 across the Levant was smooth and peaceful. The Amorite West Semitic expansion continued. Hurrians from north of Mesopotamia infiltrated into lands south of the Tigris and then penetrated quietly into Syria, even into Palestine (Ilan 1995). But this calm environment would eventually end when rivalries developed over commercial and political control of coastal Syria, for both Hatti and Mittani, the only corridor to the lucrative world of Mediterranean trade (Mazar 1990). Mittanian and Hittite raids on N Levantine corridor and coastal cities began at the end of MB2, accelerating to critical mass in the 14th century (Ilan 1995; Mazar 1990). Ahmose, the first king of Egypt's 18th Dynasty, expelled the ruling Semitic Asiatic `Hyksos' from Lower Egypt ca. 1540 BCE, launching the Levantine Late Bronze Age (hereafter, LBA)-often described as the period of Egyptian domination in Canaan and Syria.

These international struggles had a profound impact on the S Levant, and forever altered its quasi- peaceful isolationism. The Levant was now, at beginning of the LBA, sandwiched between formidable powers, aggressive and restless. Weapons such as compound and composite bows, battering rams, and chariots were introduced, exacerbating this era of tension, advancing military strategies, and siege warfare.

Over the century-and-a-half after the end of MB2, the population of the S Levant dropped 75%, not from drought or famine, but primarily as a result of Egyptian slave-raids purposefully designed to keep the hated Canaanite population in check no doubt a calculated measure to prevent a repeat of Egypts MB2 Hyksos debacle (Collins 2005).

Looking back, MBA was, without a doubt, the pinnacle of S Levantine civilization. But while the majority of sites in Cisjordan and Transjordan either limped or thrived into the Late Bronze Age, MBA civilization in the S Jordan Valley, anchored by Tall el-Hammam, never saw the dawn of LB1. From that moment—toward the end of MB2—occupation in this southernmost `circle' of the Jordan Valley ceased for the next 700 years. Focused research into the phenomenon that caused this devastation is ongoing. However, it is interesting to note that an analogous event, a fiery air-blast of cosmic origin, is now suggested to have brought about the demise of Tell Leilan, Tell Hjeira, and Tell Brak in Mesopotamia ca. 4200 BCE (Courty 2008, 2001, 1998; Weiss et al 1998).

Terminology

from Collins et al. (2015:175-176)

The previously mentioned confusion over the variable IBA nomenclature understandably cycles into the Middle Bronze Age chronology as well. The confusion results from a collision of the old way and the new way of doing Levantine chronology. The old way of subdividing the MBA (ca. 2500-1550) was to use `MB 1' (2500-1950), MB IIA (1950 - 1800), and MB IIB (1800-1550) (Dever 1987). Another old way was to divide MB1 into EB IV' (2500-2200) and `MB1' (2200-1950) (Kempinski 1992). Some archaeologists have avoided using the old term `MB 1' if they have characterized this period as generally equivalent to the new IBA. As a result, they base their terminology on three phases of the old `MB II' (ca. 1950-1550 BCE)--either given as `MBIIa' (1950-1800), `MBIIb' (1800-1600), and `MBIIc' (1600-1550); or as `MB I(1950-1800), `MB II (1800-1600), and `MB III'(1600-1550). Like A. Mazar, the directors at Tall al-Hammam have found it is extremely difficult to separate old MB IIB (new MB II) and old MB IIC (new MB III) (Ma-zar 1990). Indeed, we see no practi-cal necessity for a 50-year wisp-of-a-period like MB III (old MB IIC), as it appears to be more imagination than substance (if anything, perhaps it should be removed from the MBA altogether and integrated into LB1). Therefore, we divide our MBA ceramics and strata into MB1 (ca. 1950-1800 BCE) and MB2 (ca. 1800-1550 BCE). If ceramic trends suggest stratigraphical phasing, our system allows a great deal of specificity. For example, if necessary, MB2 can be divided into MB2e (= early MB2), MB2m (= mid MB2), or MB2/ (= late MB2).

Middle Bronze Age Architecture at Tall al-Hammam

from Collins et al. (2015:181)

... The destruction of Bronze Age Tall al-Hammam, toward the end of MB2, was violent. On both the Upper and Lower Talls, a 1–1.5 m layer of ash, strewn with broken pottery, mudbricks, and a grisly repertoire of charred remains, is clearly visible in all excavated areas. (See Figure 7.12.) In adjacent agricultural fields, one can easily see that the soil composition is dominated by prodigious quantities of grey ash, in contrast to the reddish-brown (Munsell: 7.5yr) color of the natural soil. Many of the foundation stones of the MBA fortifications are burnt and heat-fractured. Whatever the origin and nature of this conflagration, it was terminal. Both Tall al-Hammam and the adjacent S Jordan Valley remained unoccupied until IA2, about 700 years later. (See Figure 7.13.)

Bunch et al. (2021)

Abstract

from Bunch et al. (2021:1)

We present evidence that in ~1650 BCE (~3600 years ago), a cosmic airburst destroyed Tall el-Hammam, a Middle-Bronze-Age city in the southern Jordan Valley northeast of the Dead Sea. The proposed airburst was larger than the 1908 explosion over Tunguska, Russia, where a ~50-m-wide bolide detonated with ~1000× more energy than the Hiroshima atomic bomb. A city-wide ~1.5-m-thick carbon-and-ash-rich destruction layer contains peak concentrations of shocked quartz (~5–10 GPa); melted pottery and mudbricks; diamond-like carbon; soot; Fe- and Si-rich spherules; CaCO₃ spherules from melted plaster; and melted platinum, iridium, nickel, gold, silver, zircon, chromite, and quartz. Heating experiments indicate temperatures exceeded 2000 °C. Amid city-wide devastation, the airburst demolished 12+ m of the 4-to-5-story palace complex and the massive 4-m-thick mudbrick rampart, while causing extreme disarticulation and skeletal fragmentation in nearby humans. An airburst-related influx of salt (~4 wt.%) produced hypersalinity, inhibited agriculture, and caused a ~300–600-year-long abandonment of ~120 regional settlements within a >25-km radius. Tall el-Hammam may be the second oldest city/town destroyed by a cosmic airburst/impact, after Abu Hureyra, Syria, and possibly the earliest site with an oral tradition that was written down (Genesis). Tunguska-scale airbursts can devastate entire cities/regions and thus, pose a severe modern-day hazard.

Introduction

from Bunch et al. (2021:3)

... In addition to the usual debris patterns typical of ancient cities destroyed by warfare and earthquakes, the excavations of the final phase of the MB II stratum revealed highly unusual materials: pottery sherds with outer surfaces melted into glass, some bubbled as if “boiled”; melted and “bubbled” mudbrick fragments; partially melted roofing clay (with wattle impressions); and melted building plaster. These suggest that the city’s destruction was associated with some unknown high-temperature event.

The ~1.5-m-thick MB II destruction matrix also exhibited rare properties not found in the strata above or below it. Sherds from thousands of different pottery vessels were randomly intermixed and distributed throughout the depth of the matrix along with mudbrick fragments, objects of daily life, carbonized pieces of wooden beams, charred grain, bones, and limestone cobbles burned to a chalk-like consistency. At the very least, the nature of the MB II destruction matrix is highly unusual and atypical of archaeological strata throughout the ancient Near East³.

Footnotes

3. Collins, S., Byers, G. A. & Kobs, C. M. The Tall al‑Hammam Excavation Project, Season Fourteen 2019 Report: Excavation, Interpretations, and Insights (Department of Antiquities of Jordan, Amman, Jordan, 2019).

Human occupation of the Jordan Valley

from Bunch et al. (2021:3)

... Tall al-Hammam was initially occupied during the early Chalcolithic Period (~ 6600 cal BP) and was a well-established fortifid urban center by the Early Bronze Age (~ 5300 cal BP). Te city reached its peak of hegemony during the MBA and dominated the eastern half of the Middle Ghor and most likely, the western half as well. Then suddenly, the occupation of Tall el‑Hammam ceased at ~ 1650 BCE (~ 3600 cal BP) at the end of MB II, followed by an enigmatic ~ 600-year occupational hiatus. The site was not substantially occupied again until much later in the Iron Age.

The catastrophic destruction of Tall el‑Hammam

from Bunch et al. (2021:3-5)

The upper tall at Tall el‑Hammam had massive ~4-m-thick city wall foundations supporting freestanding mudbrick ramparts, multi-story mudbrick buildings including a palace complex (Fig. 2a), and a monumental gateway. Today, almost no mudbricks remain on MB II stone foundations except for a dozen or so mudbrick courses surviving on the northeast side of the 33-m-high upper tall, where no MB II mudbrick superstructure stands more than 12–15 courses high. All walls are seemingly sheared off nearly level with the tops of the upper-city wall foundations, many of which have several surviving mudbrick courses. This includes the massive palace complex that once had walls ranging from 1.0 to 2.2 m in thickness and likely rising to ~11–15 m in height.

In addition to the outer rampart surrounding the lower city, a formidable upper-city rampart-and-wall defensive system protected the acropolis palace on three sides, and a 2.2-m-thick wall separated the raised palace platform from the rest of the upper city. The rampart itself, constructed from millions of mudbricks, was as much as ~30 m thick at the base and ~7–8 m thick at the top, wide enough for military patrols. A 4-m-thick mudbrick defensive wall on stone foundations with towers lined the outer edge at the top of the rampart, rising more than 33 m above the lower city.

The ~4–5-story-tall palace complex (~52 m × ~27 m), with massive superstructures made of sun-dried mudbricks (Fig. 2a), extended ~11–15 m above the top of the enclosing rampart. The palace excavations reveal that most of the first- floor walls and all of the upper stories of the MB II palace are missing, with no evidence of collapsed walls across the entire upper tall. There are almost no whole mudbricks visible anywhere, and instead, small fragments of bricks are randomly strewn around as infill within the churned- up, 1.5-m-thick destruction matrix. It appears that most bricks were pulverized and blown off the site to the northeast. (Figs. 2b, 3; Supporting Information, Fig. S1).

On the lower tall, these general characteristics also apply. However, the MB II structures, particularly in the south, southwest, and west sectors of the lower city, seem to have suffered greater damage. For example, virtually no mudbricks survive on the stone foundations of lower-city domestic structures, even on the massive stone foundations of the 4–5-m-thick MB II city wall. Additionally, some of the large finishing stones of the city wall and associated pillar-bases of a monumental gateway show signs of heat fracturing. There are several courses of mudbricks surviving on the external towers flanking the MB II monumental gateway, but only to the height of the city wall stone foundations. The remains of the MB II stratum on the lower/outer city are largely exposed at the surface, with little to no evidence of erosional mudbrick detritus across the entire lower tall, similar to what is found on the upper tall. A heavy concentration of salt-laden ash makes up most of the shallow soil that covers the lower tall. More than 98% of the area of the lower tall was never built upon again during the 3600 years after the MB II terminal destruction³.

Although few-to-no MB II mudbrick courses remain on the lower tall, up to a dozen mudbrick courses remain on their stone foundations on the northeastern sector behind the high-rising upper-city defensive ramparts. This strongly suggests that whatever destroyed Tall el‑Hammam exhibited greater intensity across the southwest-facing sector. This also applies to the upper tall where excavated structures extend only to the height of the rampart and remaining upper-city wall foundations. Inside the depression created by the massive, surrounding defenses, all the MB II walls from 0.5 to more than 2 m in thickness are sheared off at half the height (~1.5 m) of the first story. Excavations across the entire upper and lower talls are consistent in showing the most damage on the southwest exposure of the lower city.

In summary, the few remaining mudbricks from disintegrated wall sections are mostly pulverized, rarely found intact, and sometimes reddened by fire. Across the entire upper and lower tall, the MB II terminal destruction matrix shows no signs of natural erosion by either wind or water, meaning that the missing mudbricks have not eroded over time. This means that millions of mudbricks are missing (Fig. 2b). Here, we investigate what happened to them.

Footnotes

Potential written record of destruction

from Bunch et al. (2021:5-6)

There is an ongoing debate as to whether Tall el-Hammam could be the biblical city of Sodom (Silvia² and references therein), but this issue is beyond the scope of this investigation. Questions about the potential existence, age, and location of Sodom are not directly related to the fundamental question addressed in this investigation as to what processes produced high-temperature materials at Tall el-Hammam during the MBA.

Nevertheless, we consider whether oral traditions about the destruction of this urban city by a cosmic object might be the source of the written version of Sodom in Genesis. We also consider whether the details recounted in Genesis are a reasonable match for the known details of a cosmic impact event.

Footnotes

2. Silvia, P. J. The Middle Bronze Age civilization‑ending destruction of the Middle Ghor. Ph.D. thesis, Trinity Southwest University (2015).

Study Objectives

from Bunch et al. (2021:5)

The major objective of this contribution is determining the processes involved in the high-temperature, catastrophic destruction of Tall el-Hammam, a prosperous, powerful MB-II urban center. Early archaeological excavations at Tell el-Hammam revealed the presence of unusual materials, including melted mudbrick fragments, melted roofing clay, melted pottery, ash, charcoal, charred seeds, and burned textiles, all intermixed with pulverized mudbrick. After eleven seasons of excavations, the site excavators independently concluded that evidence pointed to a possible cosmic impact. They contacted our outside group of experts from multiple impact-related and other disciplines to investigate potential formation mechanisms for the unusual suite of high-temperature evidence, which required explanation.

We conducted a wide range of analyses, using many analytical approaches that included optical microscopy, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), microprobe, focused ion-beam milling, cathodoluminescence, and neutron activation. Our group analyzed 38 elements, minerals, and other materials (Table 1), and of these, 74% (n = 28 of 38) melt at ≥ 1300 °C; 45% (n = 17 of 38) at ≥ 1600 °C; and 18% (n = 7 of 38) at ≥ 2000 °C. All represent equilibrium temperatures, which are usually a few hundred degrees higher than non-equilibrium temperatures commonly associated with oxygen-deficient (reducing) conditions present during impact events¹⁷.

Footnotes

17. Moore, A. M. T. et al. Evidence of cosmic impact at Abu Hureyra, Syria at the younger Dryas Onset (~12.8 ka): High-temperature melting at > 2200 °C. Sci. Rep. 4185 (2020).

Stratigraphy of Tall el‑Hammam

from Bunch et al. (2021:6-8)

Our investigations focused on suites of samples from four representative sampling sites, spanning a lateral distance of ~1500 m across the occupational mound of Tall el-Hammam and into the watershed beyond (Fig. 4, Supporting Information, Fig. S2). These sampling sites (the palace on the upper tall; the temple on the lower tall; and the ring road on the lower tall near the main gate) were chosen based on access to archaeologically excavated squares in the key areas of interest. The wadi site was chosen because of its location outside the city walls. The three sites in the city are separated by up to ~500 m laterally, covering an area of 5.7 ha (0.057 km2). The wadi site extends the total horizontal distance to 1500 m for all four sites. Sample collection from more distant sites outside the tall could not be conducted due to lack of access. Attempts to widen the sampling area are ongoing.

All Tell el-Hammam sampling profiles investigated contain an MB II burn layer that is highly complex and variable across the tall but is generally composed of three parts. The first part is the deepest one and is mainly pulverized mudbrick, mixed with larger melted and unmelted mudbrick fragments, melted and unmelted roofing clay, ash, charcoal, charred seeds, unburnt wood, burned textiles, bones, plaster fragments, broken pottery, and melted pottery. We call this the “debris matrix.” It varies in thickness up to ~1.5 m and is only occasionally missing across the entire tall.

The second part, immediately above the debris matrix, is composed of thin, windblown, fine-grained laminations, including fragments of broken plaster, limestone spherules, and charcoal, radiocarbon-dated to 1650 BCE. It is not present in all locations and instead is typically found on the NE sides of SW-facing wall remnants at the top of the debris matrix. This extraordinary stratum is termed the “blow-over layer.” Nothing similar has been identified in any older or younger deposits, beginning in the Early Bronze Age and extending through the Iron Age.

The third part is a charcoal-and-ash-rich stratum that we call the “dark layer,” which is found everywhere across the tall and is typically only a few centimeters thick or less. However, on the outer, southwest-facing side of the large city gate, it is ~1 m thick. Sometimes the dark layer is present on top of the blow-over layer, but other times it is the only layer found, usually resting on top of an existing interior building floor. Its depth of burial varies considerably from being near the surface on parts of the lower tall to being buried 1–4 m across most of the upper tall. The debris matrix, the blow-over, and the dark layer collectively comprise the interval of interest called the “destruction layer.”

The four sites investigated, with a difference in elevation of 52 m, are listed below from SW to NE. Almost all proxies investigated here came from these four sampling sites:

The wadi: the surface is at an elevation of ~197 mbsl on a short seasonal stream that drains the southern boundary of the tall (Fig. 4b, Supporting Information, Fig. S2). We sampled a 170-cm-thick sequence beginning ~100 cm below the surface with the destruction layer at ~160 cm below the surface. Five discontinuous samples had an average thickness of ~13.2 cm (range 10–20 cm). Four intermediate layers were not sampled. The average sample size for the wadi and the three following sites was 1200 g (range 870–2000 g).

Ring road: the surface is at ~170 mbsl on the road interior to the wall that ringed the lower city (Fig. 4c, Supporting Information, Fig. S2). The top of the 30-cm sequence is at a depth of 22 cm with the destruction layer at 42 cm. Six contiguous samples each had thicknesses of 5 cm.

Temple: the surface is at ~170 mbsl on the lower tall (Fig. 4d, Supporting Information, Fig. S2). We sampled a 43-cm sequence, with the destruction layer at 54 cm. Five contiguous samples had an average sample thickness of 8.6 cm (range 6–16 cm).

Palace: the surface is at ~145 mbsl on the upper tall (Fig. 4e, Supporting Information, Fig. S2). We sampled a 28-cm sequence with the top of the destruction layer at ~360 cm. Five contiguous samples each had an average thickness of 5.6 cm (range 3–13 cm).

Radiocarbon age of destruction layer

from Bunch et al. (2021:8)

Fig. 5

Bayesian analysis. Using OxCal v.4.4.418–20, the ‘Combine’ computer routine determined that 20 of 26 14C dates are statistically synchronous and likely represent a single event at 1661 ± 21 BCE (1686–1632 BCE), rounded to 1650 BCE. Light gray curves represent unmodeled calibrated ages; dark gray represents modeled calibrated ages. Te white dot beneath the curves equals the mean age, also represented by the red dotted vertical line. Progressively longer brackets beneath curves represent 68% and 94% confidece intervals. Te program performed two statistical probability tests to test the robustness of the model. Both the A comb and Chi Sq statistical tests show a high probability, indicating that the modeled age of 1661 ± 21 BCE is likely to be accurate.

Click on image to open in a new tab

Bunch et al. (2021)

The age of the destruction layer at Tell el-Hammam was modeled using the OxCal radiocarbon calibration program^18,19, version 4.4 (IntCal²⁰ calibration curve) with the “Combine” computer routine²⁰ (Supporting Information, Tables S1, S2). Radiocarbon dates were obtained for 26 samples from the destruction layer, and of those, three dates were rejected by OxCal as outliers that are a few decades too young, and three dates were rejected as being a few decades too old. The following datable materials were extracted from the destruction layer in Field UA in and around the palace: carbonized wood, including twigs (n=11), carbonized grains and seeds (n=3), charred organic material (n=4), organic sediment (n=1), and collagen from burned bone (n=1).

The Bayesian-modeled age for the destruction layer is 1661 ± 21 BCE (3611 cal BP) (Fig. 5; Supporting Information, Tables S1, S2) for a range of 1686–1632 BCE with a 68% confidence interval (CI, approximately equivalent to 1σ). Because of radiocarbon-dating uncertainties, the age of the destruction event has been rounded to the nearest half-century: 1650 BCE ± 50 (3600 cal BP). This age is consistent with seriation, a standard dating method used in archaeology based on the ages of stylistic changes in pottery and artifacts. This method provides an estimated age of ~1750–1650 BCE².

Discussion of the radiocarbon age for Tall el-Hammam. The accurate radiocarbon dating of the destruction layer is a necessary element of the Tell el-Hammam evidence. For maximum accuracy, Telford et al.²¹ recommended that the age of any short-term event is best constrained by using multiple dates of samples collected directly within a layer of interest. At Tell el-Hammam, we acquired datable carbon only from the clearly defined destruction layer. The seeds represent a single year and some of the charred wood is from twigs representing only a few years’ growth. These short-lived materials are among the most desirable for accurate dating, making it likely that the age range of these samples encompasses the true age of the layer.

Nevertheless, there are special difficulties with radiocarbon dating when seeking annual to decadal accuracy. For example, modern accelerator mass spectrometry (AMS) radiocarbon measurements are typically accurate only within ±20 to ±30 years. This means that a specific year cannot be assigned to a stratigraphic layer, notwithstanding the widespread but erroneous practice of relying on single-year mean dates and ignoring the uncertainties²². Instead, most radiocarbon dates have ranges of uncertainties that typically span decades. In addition, a measured date of wood may be inaccurate because of the “old wood effect,” also known as the inbuilt age^21–23. For example, the burning of a 100-year-old palace wood beam may provide an age of the Tell el-Hammam destruction layer that erroneously appears 100 years too old. Also, carbon-rich materials at archaeological sites commonly are transported vertically due to bioturbation by humans, animals, and plants and by wind-and-water redeposition, making precise and accurate dating more difficult at high chronological resolution.

Bayesian analysis has increasingly become the standard approach to produce archaeological age-depth models²² since this dating method minimizes potential stratigraphic complications. The OxCal calibration program, for example, uses a Combine routine that statistically tests the hypothesis that multiple radiocarbon dates relate to the same event. When multiple dates from a single stratum have differing radiocarbon ages, the OxCal program determines which dates have the highest probability of fitting the model, and the anomalous dates are either remodeled or rejected as outliers, thus producing a statistically accurate calibrated radiocarbon age.

Footnotes

2. Silvia, P. J. The Middle Bronze Age civilization‑ending destruction of the Middle Ghor. Ph.D. thesis, Trinity Southwest University (2015).

18. Ramsey, B. C. Bayesian analysis of radiocarbon dates. Radiocarbon 51, 337–360 (2009).

19. Ramsey, B. C. Probability and dating. Radiocarbon 40, 461–474 (1997).

20. Reimer, P. J. et al. The IntCal20 northern hemisphere radiocarbon age calibration curve (0–55 cal kBP). Radiocarbon 62, 725–757. https:// doi. org/ 10. 1017/ RDC. 2020. 41 (2020).

21. Telford, R. J., Heegaard, E. & Birks, H. J. B. All age–depth models are wrong: but how badly?. Quatern. Sci. Rev. 23, 1–5 (2004).

22. Kennett, J. P. et al. Bayesian chronological analyses consistent with synchronous age of 12,835–12,735 Cal B.P. for Younger Dryas boundary on four continents. Proc. Natl. Acad. Sci. 112, E4344–4353 (2015).

23. Schifer, M. B. Radiocarbon dating and the “old wood” problem: the case of the Hohokam chronology. J. Archaeol. Sci. 13, 13–30 (1986).

Results and Interpretations - Contents of this study

from Bunch et al. (2021:8-9)

The evidence for this investigation is multi-disciplinary and complex, and therefore, to assist with understanding the presentation, we have organized the evidence into eight major sections. A discussion follows each sub-section:

Evidence for high-temperature burning of the city
- (A1) MBA burn layer in Tall el-Hammam
- (A2) Peaks in fire-related carbon proxies
- (A3) Diamond-like carbon (diamonoids)
Melted construction materials
- (B1) Melted pottery
- (B2) Remanent magnetism of melted pottery
- (B3) Melted mudbricks
- (B4) Melted roofing clay
- (B5) Directionality of debris
High-pressure shock metamorphism
- (C1) Shocked quartz at Tall el-Hammam
- (C2) Shocked quartz grains from known airbursts
High-temperature melted minerals
- (D1) Melted quartz grains
- (D2) Melted Fe- and Si-rich spherules
- (D3) Calcium carbonate spherules and plaster
- (D4) Melted zircon grains
- (D5) Melted chromite grains
- (D6) Nuggets of Ir, Pt, Ru, Ni, Ag, Au, Cr, and Cu in meltglass
- (D7) Platinum, iridium, and palladium in sediment
- (D8) Meltglass vesicles lined with metal-rich minerals
- (D9) Melted iron and titanium
- (D10) Melted iron sulfide and iron phosphide
- (D11) Melted calcium phosphide
- (D12) Melted calcium silicate (wollastonite)
Human bones in the destruction layer
Implications of high salinity for agriculture
Coeval destruction and burning of Jericho
Potential causes of the city destruction
- (H1) Anthropogenic activities
- (H2) Pottery-making
- (H3) Normal city fires/wildfires
- (H4) Midden fires
- (H5) Warfare
- (H6) Earthquakes
- (H7) Volcanism
- (H8) Lightning
- (H9) Crater-forming cosmic impact
- (H10) Cosmic airburst
Analogous destruction events
- (I1) Comparison to Trinity atomic detonation
- (I2) Comparison to Tunguska cosmic airburst
- (I3) Hypothetical Tunguska-class airburst near Tall el-Hammam
Conclusions

Evidence for high-temperature burning of the city

MBA burn layer in Tall el‑Hammam

from Bunch et al. (2021:9-10)

The first evidence of burning relevant to this study was unearthed when excavators discovered several 6- to 7-cm-wide pieces of MB II pottery with surfaces that appeared to have been melted at high temperatures^1,3–7. Subsequently, the excavators uncovered a burn layer with a large number of melted mudbrick fragments and what appeared to be melted roofing clay^1,3–7. Such material is highly anomalous because the MBA inhabitants of the region were unable to produce fires with temperatures high enough to melt such material. These discoveries led to the investigations described in this contribution.

Several post-MBA burn layers were found on the upper tall several meters above the MB II burn layer and dated 300 years younger at ~1400 BCE during Late Bronze Age II (Fig. 6). In addition, there are two earthquake-related destruction layers buried beneath the MB II destruction layer; one dates to ~3300 BCE during the Early Bronze Age and the other to ~2100 BCE during the Intermediate Bronze Age. However, the strata marking those other events do not display the magnitude of destruction or contain any of the melted materials found in the MB II burn layer.

Discussion of city-wide burning and destruction. We considered whether Tell el-Hammam was burned and destroyed through military action in ~1650 BCE, rather than by cosmic impact. Evidence for the destruction through warfare is deduced by the presence of artifacts of war, such as arrowheads, spear points, and sling stones. However, in the MB II matrix at Tell el-Hammam, not a single arrow point or sling stone has been uncovered. Also, during its previous ~2850 years of occupation at Tell el-Hammam, there is no evidence of military activity associated with city-wide destruction or burning at any time, although there is evidence for two episodes of burning due to earthquakes.

In contrast, in Iron Age strata dating to ~1350 BCE, ~300 years following the MB II destruction event, the presence of numerous sling stones suggests military action. In addition, the Iron-Age-II city on the upper tall was destroyed by military conquest in the late ninth century BCE. Thus, military action has been detected at Tell el-Hammam but not in the 1650-BCE destruction layer. In each case of military destruction, there are no examples of melted pottery or mudbrick.

Military action has also been documented at nearby Jericho, 22 km west of Tell el-Hammam. However, no evidence for military conquest has been detected in the 1650-year-old occupation level at Jericho, which shows evidence of intense burning and destruction, as at Tell el-Hammam. In a previous episode of warfare, defensive walls were breached at ~2000 BCE, after which the site displayed different pottery, weapons, architecture, and burial customs, as is typical of military conquest²⁴. Similarly, between 1950–1800 BCE, Jericho suffered violent destruction indicative of military action²⁵. Neither of these episodes is apparent at Tell el-Hammam and no melted materials have been reported at Jericho.

At Tall Nimrin, the third-largest city in the area located ~5 km to the north of Tell el-Hammam, there also is no evidence for MB II warfare at 1650 BCE, although there is evidence of destruction and possible burning, as at Tell el-Hammam. Also, there is evidence of military action during the Iron Age II period, as at Tell el-Hammam. Thus, the three largest urban cities in the southern Jordan Valley, Tell el-Hammam, Jericho^26,27, and Tall Nimrin²⁸, burned and/or were destroyed simultaneously at ~1650 BCE, the end of MB II, but lack evidence for military action as a potential cause. Of all the layers in the three cities showing evidence of military or other types of destruction, e.g., earthquakes, none contain any reported evidence of high-temperature proxies, including melted mudbricks, pottery, or roofing clay.

Footnotes

1. Collins, S. W. et al. (2015) Tall el-Hammam: Excavation Report Season 2014. In The Madaba Plains Project.

3. Collins, S. W. et al. (2009) Preliminary report on the 2008 excavation season at Tall el-Hammam. Annual of the Department of Antiquities of Jordan 53, 385–414.

4. Collins, S. W. et al. (2011) Tall el-Hammam excavation report Season 2010. Annual of the Department of Antiquities of Jordan 55, 171–200.

5. Collins, S. W. et al. (2013) Tall el-Hammam excavation report Season 2012. Annual of the Department of Antiquities of Jordan 57, 207–238.

6. Collins, S. W. et al. (2015) Tall el-Hammam: Season 2013 excavation report. Annual of the Department of Antiquities of Jordan 59, 325–356.

7. Collins, S. W. et al. (2016) Tall el-Hammam excavation report Season 2015. Annual of the Department of Antiquities of Jordan 60, 263–292.

24. Kenyon, K. M. (1981) Excavations at Jericho, Vol. 3: The Architecture and Stratigraphy of the Tell. British School of Archaeology in Jerusalem.

25. Garstang, J. (1934) Jericho: City and Necropolis. Liverpool Annals of Archaeology and Anthropology 21, 3–67.

26. Kenyon, K. M. (1979) Excavations at Jericho, Vol. 1: The Tombs Excavated in 1952–54. British School of Archaeology in Jerusalem.

27. Kenyon, K. M. (1981) Excavations at Jericho, Vol. 3: The Architecture and Stratigraphy of the Tell. British School of Archaeology in Jerusalem.

28. Flanagan, J. W. & McCreery, D. W. (1990) Excavations at Tell Nimrin: Preliminary report. Annual of the Department of Antiquities of Jordan 34, 193–206.

Peaks in fire‑related carbon proxies

from Bunch et al. (2021:11)

Our analyses reveal a major peak of carbon in the palace destruction layer (Fig. 7), where the loss-on-ignition (LOI) value for the charcoal-rich layer is 43.7 wt.% (Supporting Information, Table S3). Background LOI values in two samples above and two below the destruction layer average ~23.4 wt.%, for a difference of ~20 wt.%. The background LOI values are inferred to represent mostly carbonate, which is common in Tell el-Hammam sediment; the increase of ~20 wt.% in LOI value for the destruction layer is inferred to be organic carbon.

In another test of organic carbon content, we added water to ~100 g of sediment for 10 contiguous samples from the palace and collected the float. Inspection by optical microscopy confirmed that the float from the destruction layer contained mostly charred organic material, e.g., soot, ash, charcoal, wood, and plant fragments at 1.7 wt.% of bulk sediment, while the layer beneath it contained 0.1 wt.%. The other eight strata contained no detectable float.

Sedimentary soot was analyzed in one sample of the destruction layer from Field UB, located behind the palace. The sample was mostly silty, calcareous sand with no visibly apparent charcoal, wood, or textiles. It contained an average of 1.0 wt.% total organic carbon (TOC) with a high ratio of soot carbon to total organic carbon (soot/TOC), averaging 75.8% (range 55.7–95.8% in two aliquots). This high ratio in the destruction layer is consistent with intense biomass burning that converted most organic matter into soot via condensation of combustion- derived gases.

Diamond‑like carbon (diamonoids)

from Bunch et al. (2021:11-13)

Nanodiamonds and diamond-like carbon have been used as indicators of cosmic impacts, including at the Cretaceous–Paleogene boundary (K–Pg) at ~65 Ma^29,30 and the Younger Dryas boundary (YDB) at 12.8 ka³¹. Kinzie et al.³¹ concluded that impact-related nanodiamonds and diamond-like carbon (DLC or diamonoids) are produced from the pyrolysis of carbon sources, e.g., vegetation and carbonate rocks that were pyrolyzed during high-temperature, high-pressure airburst/impact events. To search for nanodiamonds in Tell el-Hammam sediment, we followed the protocol of Kinzie et al.³¹, who used multiple reagents to remove all minerals except refractory, acid-resistant carbon.

In six samples of Tell el-Hammam bulk sediment from the temple (LS42J), we searched for, but were unable to detect the presence of nanodiamonds, but did observe carbon atoms clustered into irregularly shaped plate-like clumps. Examination using bright-field high-resolution transmission electron microscopy (HRTEM) reveals short-range carbon structures, typically composed of fewer than 1–2 dozen atoms (Fig. 8). Analyses by transmission electron microscopy (TEM) and selected-area electron diffraction (SAD) indicate that the structures are composed of quasi-amorphous carbon that does not produce SAD patterns (Fig. 8c), even though organized, short-range structures are present (Fig. 8b).

This material is commonly referred to as diamonoid or diamond-like carbon (DLC)³¹, representing the smallest unit observed in a diamond crystal lattice. These structures are nearly as hard as diamond and are stable at temperatures up to ~1000–1200 °C³¹. Diamonoids were observed in all samples investigated, but abundances peaked at ~3 ppm in the temple destruction layer. This value is more than three times higher than background concentrations that average 0.9 ppm (range 0.4–1.9 ppm) both above and below the destruction layer.

When viewed using optical microscopy, these nanocrystals appear clear to translucent white (Fig. 8d), as is typical of diamonoids and diamond-like carbon³², as distinguished from opaque, non-diamond forms of carbon that are commonly black or gray. When the same field of residue was exposed to ultraviolet light sources, the carbon-rich residue luminesced (Fig. 8e) at some of the characteristic luminescence bands for diamond, 365 nm (long-wave UV) and 440 nm³³.

One fragment of melted pottery from the palace exhibits the results of the impact of a 30-µm-wide carbon-rich particle (Fig. 9). Using optical microscopy, the particle is whitish and translucent-to-clear, the same as the diamonoids extracted from sediment. SEM–EDS analyses indicate that this particle is an aggregate of hundreds of discrete plate-like amorphous carbon grains, along with a few micron-sized grains of Si, Ca, and Al oxides. The individual grains are anhedral with no apparent structure, resembling TEM images of Tell el-Hammam diamonoids.

Discussion of diamonoids. Diamond-like carbon or diamonoids are found associated with extraterrestrial impact events³⁴ but are also found in hydrocarbon deposits and coal³⁴. Each diamonoid typically contains carbon atoms that are sp3-bonded (i.e., three bonded carbon atoms), as in diamond, rather than with sp2 bonding (i.e., two bonded carbon atoms), typical of graphite³⁴.

Although diamonoids peak in the temple destruction layer, indicating likely exposure to high temperatures, they are also present at lower concentrations in all other layers. This may be due to the reworking of the nano-sized diamonoids, which are easily redeposited by wind and water.

The carbon-rich aggregate that is fused to the melted surface of the pottery is whitish-to-clear (Fig. 9), and so we propose that this object is a cluster of diamonoids. The particle appears to have had sufficient velocity to produce a crater in the molten potsherd. If so, the velocity was low enough not to have shattered the low-mass, high-energy particle and yet high enough to have pushed aside the viscous molten glass.

Footnotes

29. DeCarli, P. S. et al. (2002) Nanodiamonds in the Cretaceous– Paleogene boundary layer. Science 297, 1421–1424.

30. Hough, R. M. et al. (1997) Diamonds from the Cretaceous– Tertiary boundary. Nature 387, 357–360.

31. Kinzie, C. R. et al. (2014) Nanodiamonds and diamond-like carbon from the Younger Dryas boundary. Proceedings of the National Academy of Sciences 111, 14681–14686.

32. Plescia, J. B. et al. (2012) Characterization of diamond-like carbon in impact deposits. Meteoritics & Planetary Science 47, 1347–1360.

33. Davies, G. (1974) The optical properties of diamond. Reports on Progress in Physics 37, 591–648.

34. Dahl, J. E. et al. (2003) Isolation and structure of higher diamondoids, nanometer-sized diamond molecules. Science 299, 96–99.

Melted construction materials

Melted pottery

from Bunch et al. (2021:13-15)

Surface-melted potsherds were found about 15 m northeast of the palace complex in the destruction layer in Field UB (Fig. 10). These were associated with numerous unmelted potsherds within a sealed MB II context that is deeply buried in undisturbed sediment beneath ~2.5 m of Iron Age walls, indicating that melted potsherds were not redeposited from younger strata. Their MB II age was determined by seriation (pottery styles) and radiocarbon dating of associated materials, typically charred seeds and grains. The potsherds were mixed within a heavily churned debris matrix, containing charcoal, ash, pulverized mudbrick, potsherds, roofing materials, and fragments of limestone building plaster. No melted material was found anywhere in the city in younger or older layers, spanning ~3500 years, including from the Early Bronze Age (3300–2300 BCE), Late Bronze Age (1550–1200 BCE), Iron Age (1200–332 BCE), and Early Roman times (63 BCE–135 CE).

One melted potsherd analyzed from Square 10JJ in the palace (Fig. 10a, b) came from the shoulder/neck transition of a wheel-made MB II storage jar. The sherd was constructed from tan-colored, gritty, sandy clay and has a maximum thickness of ~1 cm. The sliced edge shows that only the outer 2 mm of the sherd were altered to glass, while the next 4 mm of clay were darkened by thermal exposure but not melted; the inner 4 mm of the sherd matrix are unmelted (Fig. 10e, f). Photomicrographs and SEM images show that the outer surface of the potsherd is relatively smooth, glossy glass, indicating high-temperature melting and entrainment of porosity, followed by rapid quenching. The inside is unmelted. Most of the edges of the potsherd are highly vesicular (Fig. 10g, h), and once-molten clay drapes over some of the broken edges, suggesting that melting of the sherd took place following breakage. The inner portion of the sherd that is visible on the broken or sliced edges appears to be original unaltered clayey sand with few voids (Fig. 10f, g). On the interior surface of the potsherd, mineral inclusions are unmelted. On the other hand, most minerals embedded in the exposed or exterior surface of the potsherd exhibit significant melting during which the matrix was transformed into greenish, translucent glass.

Another melted potsherd came from the temple in the lower tall, closely associated with sherds of unmelted MB II pottery. One sherd (Fig. 10c, d) is part of a typical red clay pot. The average thickness of the sherd is 5 mm, but only the outside 2 mm of the sherd had been altered into a highly vesicular glass. The middle 1 mm of clay is darkened, presumably by thermal exposure but is not melted. The bottom 2 mm of clay retains their original red color and are unmelted. The curvature of the sherd shows that melting was limited to the outside of the pot’s exterior or exposed surface. In SEM images, the edges of this sherd appear unmelted, while the outer surface is melted and highly vesicular, indicating exposure to high temperatures. Many minerals embedded in the surface are partially or fully melted, while most minerals contained within the matrix are unmelted.

SEM/Energy Dispersive X-Ray Spectroscopy (SEM–EDS, using a large spot size) and microprobe analyses of both sherds indicate similar compositions. They are dominantly composed of SiO2 at ~48.6 average wt.%; CaO at ~17.5 wt.%; and Al2O3 at ~15.0 wt.% (values for other oxides are provided in Supporting Information, Tables S4, S5). The Ca-rich matrices contain abundant crystals of plagioclase and pyroxene. The composition of the clay used to make the pottery is smectite (montmorillonite) with a high percentage of calcium hydroxide due to weathering of the abundant local limestone. When mixed with quartz as a binding agent, this type of clay was extensively used by regional cultures for centuries as the standard raw material for pottery.

Discussion of melted pottery, heating experiments. We investigated the melting point of Tell el-Hammam pottery by conducting heating experiments on unmelted pottery from the MB II destruction layer. First, we used Differential Scanning Calorimetry with Thermogravimetric Analysis (DSC–TGA). DSC measures the heat flow of a sample over a temperature range and TGA measures the weight change of a sample over the same temperature range. We observed a 32.7% weight loss between ~381 and 831 °C but with only an additional 0.5 wt.% weight loss after ~831 °C during heating to ~1400 °C (Supporting Information, Fig. S3b). This indicates that the powder gave off physically and chemically bound volatile materials (e.g., H2O and CO2) during the ramp-up to 831 °C, with minimal subsequent outgassing. During cooling, the sample showed no further weight change, as expected in an argon atmosphere.

The DSC results demonstrated a large endothermic peak coinciding with the decomposition/weight loss of the sample during the temperature increase to ~831 °C. There was an increase in heat flow at ~1150 °C and again at ~1310 °C, suggesting exothermic reactions possibly due to the recrystallization of the phases present. The powdered pottery retained its crystalline, irregular granule morphology after DSC heating to 1400 °C, the maximum temperature achievable in this experiment. These results therefore indicate melted potteries were exposed to temperatures at Tell el-Hammam of >1400 °C.

Independent studies show that the typical melting point of clay ranges from ~1200° to 1600 °C³⁵. Using the average bulk analysis of the pottery of CaO at ~17.5 wt.%, SiO2 at ~48.6 wt.%, and Al2O3 at ~15.0 wt.%, the theoretical minimum melting point of the pottery is between 1300° and ~1500 °C, according to the CaO–Al2O3–SiO2 (CAS) ternary phase diagram³⁶ (Supporting Information, Fig. S3a). These theoretical calculations are consistent with the heating experiment which showed no detectable melting at ~1400 °C.

To further investigate the melting point of pottery, we conducted laboratory experiments using an oxygen/propylene torch and thermocouple. After full exposure for ~2 min, one fragment of unmelted Ca-rich palace pottery began melting at ~1500° ±25 °C (Supporting Information, Fig. S4). Although the temperature and heat flux were sufficient to melt a small area of the potsherd, the experiment was unable to duplicate the extensive melting observed on melted Tell el-Hammam potsherds. In addition, quartz grains embedded in the pottery remained unmelted. This result suggests that the maximum exposure temperature for the excavated melted potsherds was higher than 1500 °C and the flux rate was higher.

Footnotes

35. Omotoyinbo and Oluwole (2008)

36. Kovali and Pekcan (1995)

Remanent magnetism of melted pottery

from Bunch et al. (2021:15)

Because storage pots had, at times, been placed on the roofs of buildings at Tell el-Hammam, we explored the possibility that the melted pottery and mudbricks may have been struck by lightning, causing flash-melting. We used the same technique as in Moore et al.¹⁷ for measuring remanent magnetism, the magnetization remaining after Fe-rich materials cool while exposed to Earth’s ambient magnetic field (i.e., geomagnetism³⁷). Remanent magnetism can vary from fully magnetized, i.e., saturated, as may occur during lightning strikes, to fully demagnetized, i.e., desaturated.

Two samples of melted pottery from Tell el-Hammam were analyzed: TeH_VITPOT_1 at 20.6 g and TeH_VITPOT_2 at 113.5 g. The measurements of remanent magnetism in both samples were nearly the same. The results are consistent with the samples having cooled while exposed to Earth’s normal geomagnetic field (Supporting Information, Fig. S5). They do not exhibit any evidence of intense magnetic fields generated during lightning discharges, meaning that it is highly unlikely that the Tell el-Hammam potsherds were melted by lightning strikes. For an example of the magnetization of rock by an electric discharge, see Kletetschka et al.^38–41 and Wasilewski and Kletetschka⁴².

Footnotes

17. Moore et al. (2020)

37. Tarduno et al. (2015)

38. Kletetschka et al. (2004)

39. Kletetschka et al. (2006)

40. Klokočník et al. (2020)

41. Reddy et al. (2019)

42. Wasilewski and Kletetschka (2008)

Melted mudbricks

from Bunch et al. (2021:15-16)

MB II mudbricks in the Tell el-Hammam destruction layer are present in varying states of preservation. They are occasionally found whole or partially broken but typically are highly fragmented or pulverized. Both melted and unmelted mudbricks vary in color through shades of red, brown, gray, and black (Fig. 11). Because melted mudbricks are typically indistinguishable from melted sediment, which is mostly composed of pulverized mudbricks, for simplicity we refer to all of this material as “melted mudbricks.” The abundances of melted material spanned a wide range: ~0.6 g/kg along the ring road (Fig. 12a); ~0.1 g/kg in the temple (Fig. 12b); ~5 g/kg in palace location 7GG (Fig. 12c); and ~150 g/kg in palace room 7HH (Fig. 12d) (Supporting Information, Table S3). None was observed in the wadi.

On the upper tall, melted mudbricks were found in the MB II destruction layer within the palace, Field UA, in six different excavation squares. Typically, the thickness of melting is ~1–5 mm. Melted mudbricks (with melted pottery and roofing clay) were found ~2 m below the surface, mixed within a 30-cm-thick matrix of broken pottery and decomposed unmelted mudbrick. The destruction matrix also contained ash, charcoal, charred and unburnt roofing beams, charred and uncharred grains, and burned fabric and bedding. The density of mudbrick meltglass in the most concentrated pockets reached >50% by volume, and in some cases fractured chunks of melted material were found in pockets several meters in diameter and up to 30 cm thick. Between these pockets, the density trailed off to 10–15% by volume. The melted mudbrick fragments were typically surrounded by decomposed mudbrick and were rarely found with ash or charcoal, suggesting that they had melted before landing in their final locations.

A layer of melted mudbrick was often found overlain by ~15–30 cm of melted and unmelted roofing clay. Typically, this melted clay was many times more abundant than melted mudbricks. In a 12 m × 12 m part of Field UA, melted clay roofing material was covered by a variable thickness of up to 1 m of relatively homogeneous, decomposed- to-whole, unmelted mudbricks of the Late Bronze Age. Above this small LBA footprint, when present, the uppermost meters consisted of a matrix of decomposed mudbrick, broken Iron Age pottery, and architectural debris, none of which was melted.

Unbroken upper surfaces of the melted material are typically relatively smooth, and the broken surfaces are often highly vesicular, as shown in SEM images (Fig. 11d–f). The lower surfaces sometimes display partially fused sand grains. Optical microscopy and SEM imagery reveal that the broken interior surfaces typically contain mineral inclusions that are mostly unmelted, although some are partially melted. The outer melted surfaces often contain mineral grains that are partially to fully melted. Scratch testing showed that the melted material will scratch glass but not quartz, indicating a Mohs hardness of between 5.5 (glass) and 7 (quartz).

The composition of the meltglass (collectively, melted mudbrick and roofing material) closely matches that of the melted pottery, dominantly composed of SiO2 at 48.1 wt.%; CaO at 17.2 wt.%; Al2O3 at 2.5 wt.%; and C at 14.1 wt.% (Supporting Information, Tables S4, S5). Phosphate percentages in melted mudbrick vary from 6 to 16 wt.%, and its presence can lower the melting point. The ternary phase diagram for the melted mudbrick shows a theoretical melting point between ~1300° to 1500 °C (Supporting Information, Fig. S3a).

Discussion of melted mudbricks. Some minerals (e.g., calcite (CaCO3) and soda ash (Na2CO3) present in the mudbricks and bulk sediment can act as fluxing agents to lower the equilibrium melting point. To investigate the fluxing effect at Abu Hureyra, Syria, Moore et al.¹⁷ conducted heating experiments on Ca–Al–Si bulk sediment that is geochemically similar to the sediment at Tell el-Hammam. Laboratory temperatures were increased from ~1100 to ~1850 °C in increments of 50–150 °C. Bulk sediment melted at ~1250 °C, establishing a likely minimum melting point for Tell el-Hammam melted mudbricks and sediment.

Footnotes

17. Moore et al. (2020)

Melted roofing clay

from Bunch et al. (2021:17-18)

Melted clay material is associated with MB II roofs and upper-story floors at Tell el-Hammam that were built using large wooden beams that spanned the mudbrick walls. These large beams were overlain by smaller wooden crossbeams, which were, in turn, covered with straw and leaves (Fig. 13a), topped with multiple layers of dried clay that were individually troweled flat and smooth. Melted roofing clay was associated with ash, charcoal, charred beams, and burned textiles, which suggests exposure to high-temperature fire. Most of the roofing clay displays imprints of original roof construction material, e.g., straw, plant stems, and leaves (Figs. 13, 14). Typically, the depth of melting is ~1–5 mm.

SEM analyses indicate that most of the imprints also exhibit siliceous plant components, including phytoliths, parenchyma cells, stomata, and siliceous plant fibers, all of which appear to be fused into the roofing clay at high temperatures. Scratch testing indicated that the hardness of the plant-imprinted roofing clay was between 5.5 (glass) and 7.0 (quartz) on the Mohs scale.

Discussion of melted roofing clay. Exposure to high temperatures is inferred to have vaporized the water and carbon from the plant material and then fused the clay into hard vitrified masses. This process appears similar to that documented for proposed airburst/impact materials at Abu Hureyra, Syria¹⁷, and Dakhleh Oasis, Egypt⁴³.

The clay imprints of siliceous plant material are inferred to have been made by biogenic hydrated silica (SiO2·H2O). Plants use dissolved silica from soils to produce Si-rich cell walls and connecting tissue that increases the plants’ rigidity, toughness, and herbivore resistance^44,45. After combustion, these decay-resistant siliceous structures retain their original morphologies¹⁷. This siliceous material can be freed from surrounding plant tissue by fire at ~450–550 °C but does not melt at such low temperatures⁴⁶. Moore et al.¹⁷ reported laboratory experiments with an oxygen/propylene torch in which temperatures of >1250 °C were required to fully melt siliceous plant material embedded in Ca–Al–Si meltglass.

Footnotes

17. Moore et al. (2020)

43. Poreda et al. (2010)

44. Epstein (1994)

45. Perry and Keeling-Tucker (2001)

46. Yoshida et al. (1987)

Directionality of debris

from Bunch et al. (2021:18-21)

Figures

Directionality Images

Normal Size

Fig. 15 Destruction of the
Fig. 15

The directionality of mudbricks, potsherds, and grains

400-kg quern, at left, used for grinding grain, is tipped over with top towards NE. Image view spans~2.5 m. Area #1 shows broken pottery and meltglass piled against quern from SW to NE (arrow). Area #2 contains charcoal, charred grains, ash, and mudbrick fragments, but no potsherds, suggesting that the quern shielded the floor to the NE. The area at the top labeled ‘blow-over’ is evidence that strong winds sealed the deposit with windblown laminated material that includes pulverized mudbrick, charcoal, ash, and fragments of white plaster. The draping of the blowover indicates debris traveled from SW to NE. The scale stick is in 10-cm intervals

Directional potsherds. Blue, red, and green asterisks (*) represent color-coded potsherds from three different pots. Arrows mark the motion of potsherds from SW to NE, spanning ~1 m. Area #1 represents the inverted bottom of the pot with its smaller fragments strewn to the left. Some pots contained charred grains also strewn in a SW-to-NE direction. Radiocarbon dates on charred grains confirm an age of ~1650 BCE (3600 cal BP)

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 16 Destruction of the
Fig. 16

High-velocity effects

Photo of an excavated section of the palace wall on upper tall. In the center are the lower courses of the mudbrick wall (#1a, between white dashed lines) and foundation (#1b). Yellow dashed line with arrow indicates wind direction of blow-over to NE. Also, note the lines of white fragments of broken plaster at two blue arrows (#4), where the curved wall top displays intense wind abrasion. At the right side of the image, #6 marks the limit of modern excavation. The sequence of wall destruction is illustrated in panels ‘b’ to ‘e’ below.

An artistic depiction, re-creating the pre-destruction mudbrick wall and foundation highlighted in red (#1)

Rubble in red (#2) was blown against the SW-facing side of the wall; material mainly consists of pulverized mudbricks and shattered potsherds

Section of wall higher than several courses of mudbrick was demolished and blown to the NE to form the debris matrix (#3)

High-velocity winds blew from SW to NE (arrows), severely abrading the top of the wall, and burying it in debris. Winds produced the laminated ‘blow-over’ (#4), containing small pulverized mudbricks, fragments of white wall plaster, and limestone spherules stripped from interior walls. Settling on top, the ‘dark layer’ (#5) is mostly composed of charcoal and ash from the city-wide fires, along with post-destruction fine particulates

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 17 Directionality of

Fig. 17

The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide).

Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html).

Click on image to open in a new tab

Bunch et al. (2021)

debris across the entire Tall el-Hammam site from Bunch et al. (2021)

Magnified

Fig. 15 Destruction of the
Fig. 15

The directionality of mudbricks, potsherds, and grains

400-kg quern, at left, used for grinding grain, is tipped over with top towards NE. Image view spans~2.5 m. Area #1 shows broken pottery and meltglass piled against quern from SW to NE (arrow). Area #2 contains charcoal, charred grains, ash, and mudbrick fragments, but no potsherds, suggesting that the quern shielded the floor to the NE. The area at the top labeled ‘blow-over’ is evidence that strong winds sealed the deposit with windblown laminated material that includes pulverized mudbrick, charcoal, ash, and fragments of white plaster. The draping of the blowover indicates debris traveled from SW to NE. The scale stick is in 10-cm intervals

Directional potsherds. Blue, red, and green asterisks (*) represent color-coded potsherds from three different pots. Arrows mark the motion of potsherds from SW to NE, spanning ~1 m. Area #1 represents the inverted bottom of the pot with its smaller fragments strewn to the left. Some pots contained charred grains also strewn in a SW-to-NE direction. Radiocarbon dates on charred grains confirm an age of ~1650 BCE (3600 cal BP)

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 16 Destruction of the
Fig. 16

High-velocity effects

Photo of an excavated section of the palace wall on upper tall. In the center are the lower courses of the mudbrick wall (#1a, between white dashed lines) and foundation (#1b). Yellow dashed line with arrow indicates wind direction of blow-over to NE. Also, note the lines of white fragments of broken plaster at two blue arrows (#4), where the curved wall top displays intense wind abrasion. At the right side of the image, #6 marks the limit of modern excavation. The sequence of wall destruction is illustrated in panels ‘b’ to ‘e’ below.

An artistic depiction, re-creating the pre-destruction mudbrick wall and foundation highlighted in red (#1)

Rubble in red (#2) was blown against the SW-facing side of the wall; material mainly consists of pulverized mudbricks and shattered potsherds

Section of wall higher than several courses of mudbrick was demolished and blown to the NE to form the debris matrix (#3)

High-velocity winds blew from SW to NE (arrows), severely abrading the top of the wall, and burying it in debris. Winds produced the laminated ‘blow-over’ (#4), containing small pulverized mudbricks, fragments of white wall plaster, and limestone spherules stripped from interior walls. Settling on top, the ‘dark layer’ (#5) is mostly composed of charcoal and ash from the city-wide fires, along with post-destruction fine particulates

Click on image to open in a new tab

Bunch et al. (2021)
multi-storied palace from Bunch et al. (2021)
Fig. 17 Directionality of

Fig. 17

The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide).

Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html).

Click on image to open in a new tab

Bunch et al. (2021)

debris across the entire Tall el-Hammam site from Bunch et al. (2021)

Discussion

During 15 field seasons at Tell el-Hammam, there have been extensive excavations of ~100 squares (each ~6 × 6 m in size) spread across the upper and lower tall. On Tell el-Hammam occupational surfaces older and younger than the MB II destruction layer, whole and broken pottery were nearly always found with all fragments confined to a small area that was their “working space.”

In contrast, the destruction layer exhibits a distinct orientation pattern marking the movement of objects across the MBA-age excavated floors. Out of about 2000 different vessels represented in the palace destruction matrix, most are fragmentary, and not a single one, smashed or otherwise, has been found in its “working” place on a floor or other surface. Instead, nearly all pottery vessels were broken and strewn in a narrow SW-to-NE orientation spanning up to 10 m. On the rare occasions when intact or nearly intact ceramic vessels were found, they were seldom found on the SW side of walls, but rather were protected on the NE side of walls, often tilted to the NE and embedded in the destruction matrix.

For example, the excavators uncovered an MBA-age food preparation room in the palace with more than 150 separate pottery vessels (some shown in Fig. 15). Shattered MB II potsherds were strewn across the palace floors from SW to NE, nearly always located within the bottom ~20 cm of a churned-up debris matrix that ranged in thickness from 50 to 150 cm. Grains, such as barley, that had been stored in some of the pots were also distributed from SW to NE, interspersed among the trail of potsherds.

In another notable example, a distinctively decorated pot was found in pieces spread narrowly across ~6 m, with the majority of its decorated fragments concentrated against the SW-facing wall of the room. Broken potsherds from at least 50 separate vessels of all sizes have been found on this surface, and all pieces were strewn in the SW-to-NE direction. Figure 15b shows three examples of shattered pots with potsherds strewn in narrow paths across >60 cm in a SW–NE orientation. Before being excavated, they were embedded in pulverized mudbrick from the destruction layer.

This pattern of directionality was also observed for larger objects. Within the sealed, undisturbed MB II context of the palace, excavators uncovered a heavy saddle quern (weight: ~400 kg or 880 lb; dimensions: ~90 × 50 × 40 cm). Made of dense local stone and used for grinding grain, the quern was found toppled from its dirt pedestal and tipped on its side on the floor of a food preparation area (Fig. 15a). The geometric axis of the quern aligns with the SW–NE direction. Barley grains that had once been on top of the quern were found carbonized and strewn across the floor ~1 m to the NE between the overturned quern and the SW-facing wall, suggesting SW-to-NE movement (Fig. 15a). Radiocarbon dating of carbonized wood and grain from this floor confirms ~1650 BCE (~3600 ±50 cal BP) as the date for the destruction event.

Discussion of directionality. An inferred sequence of events that produced the destruction layer (collectively the lower debris matrix, the blow-over above it, and the upper charcoal-rich dark layer) is shown in Fig. 16. Over a brief span of seconds, a high-velocity, debris-entrained shock wave arrived from the SW, demolished the mudbrick walls of the city, blew over the fallen walls, severely abrading (sand-blasting) the top surfaces, and deposited thin laminations of pulverized mudbrick, fragments of crushed building plaster, limestone spherules, ash, and charcoal, typically 20–30 cm thick (Fig. 16e). The wind demolished the portions of walls and ramparts that extended higher than several courses of mudbrick.

Along interior walls, melted mudbrick, broken pottery, wall plaster, charred beams, and other interior debris were pushed against the SW-facing sides of walls that were typically 60–70 cm thick (Fig. 16c), filled the remaining space with pulverized debris (Fig. 16d), and blew the remainder off the tall to the NE. This sequence of fallen walls, capped by blow-over layers, appears to have occurred nearly instantaneously because there is no evidence of erosion or passage of time between the top dark layer, the blow-over layers, and the underlying debris matrix.

Significantly, above the destruction layer, there is no evidence for extensive human occupation at Tell el-Hammam for ~600 years. Instead, gradual sediment erosion and redeposition buried the entire destruction layer. After that long hiatus, the city was only minimally rebuilt during the Iron Age and never returned to its former size and level of occupation.

Evidence of directionality from SW to NE within buildings has been identified in ~100 excavated squares across the site. Directionality is indicated for up to six materials:

melted pottery

melted mudbricks

blow-over detritus

general building material

seeds and grains

potsherds

Notably, all excavated squares, including the palace, temple, and ring road (Fig. 17), display evidence of SW–NE-trending blow-over materials, primarily composed of thinly laminated layers of pulverized mudbrick, ash, charcoal, and fragments of white plaster.

Following the destruction event, archaeological evidence indicates that the city was only minimally rebuilt ~600 years later during the Iron Age. When that occurred, there is no apparent evidence that later inhabitants recycled surviving mudbricks for rebuilding the city. In any event, later structures are far too few to account for the massive number of missing mudbricks. Nearby cities were not rebuilt either, so no mudbricks from Tell el-Hammam could have been used for that purpose.

Furthermore, the city foundations are sealed by pulverized mudbrick and charcoal that dates to ~1650 BCE throughout the city, indicating the destruction layer has remained undisturbed for >3600 years until modern times. In summary, the evidence is consistent with the hypothesis that the city’s mudbrick walls were pulverized by hypervelocity winds from a high-temperature event of cataclysmic proportions and the debris was blown off the tall to the NE.

High‑pressure shock metamorphism

Shocked quartz at Tall el‑Hammam

from Bunch et al. (2021:21-25)

To further test the hypothesis that a cosmic airburst/impact event destroyed Tell el-Hammam, we searched for shocked quartz, one of the most commonly accepted cosmic impact indicators^47–50. When quartz grains are exposed to shock compression during a cosmic impact event, they develop both irregular and regular microfractures, including planar fractures (PFs), short feather fractures (FFs), and/or planar deformation features (PDFs)^51,52. Here, we refer to them collectively as “shock lamellae.” Impact-shocked grains display one or more sets of shock lamellae that are aligned with quartz’s crystallographic axes. Conversely, natural quartz has no visible crystallographic cleavage but may display randomly oriented non-parallel fractures.

We used multiple analytical techniques to examine quartz grains from the destruction layer in the palace (7GG) (Figs. 18, 19) and the temple (LS42K) (Fig. 19). We prepared two microscope slides, each containing ~2000 quartz grains that were thin-sectioned, polished, and etched with hydrofluoric acid (HF) (see Methods). Next, the slides were examined using optical microscopy to identify grains displaying potential lamellae; SEM–EDS was used to confirm the quartz composition and to image any visible lamellae; cathodoluminescence (CL) was used to investigate luminescence; and a universal stage, or U-stage, was used to investigate polarization and to record the azimuth and inclination of lamellae^49,53,54. Finally, the crystallographic axes were plotted with the ANIE indexing program⁵⁵ and compared to those of quartz (Fig. 20).

The results show that an average of ~1 in 800 Tell el-Hammam quartz grains (n=7 crystallites in 5 grains) display shock lamellae, ranging in thickness from < 1–2 µm with an inter-lamellar spacing of ~1–10 µm with most lamellae in the 2–5-µm spacing range. For all grains, most shock lamellae are discontinuous and do not fully extend across any given quartz grain. Most lamellae appear parallel to sub-parallel, and some are straight, but others appear curved, all of which have been reported at known impact sites, such as Meteor Crater, AZ⁴⁷. In particular, the Charlevoix crater displays shocked grains with curved lamellae, deformation bands, micro-fractures, planes commonly oriented to (0001), and serrated (stair-step) plane boundaries⁵⁶, all of which are observed at Tell el-Hammam. See Table 2 for details. Two grains display one set of lamellae oriented along the basal plane (0001); one crystallite has 3 sets of lamellae; 3 grains/crystallites display two sets; and 3 display one set of lamellae each. Note that for the 2 single-set grains that are sub-parallel to the c-axis, the indexing results are equivocal and only estimated because there is no uniquely measurable azimuthal relationship within each grain. Even so, the results are consistent with the relationship between the c-axis and the indexed planes.

Optical microscopy and SEM imaging show that the shock lamellae commonly display asymmetry, the condition in which one side of a lamella appears darker and the other side brighter⁵⁷. This difference is attributed to higher values on the bright side for density, refractive index, and/or birefringence⁵⁷. Asymmetry is apparent for all shocked quartz grains from both the palace and temple. SEM imaging detected feather fractures (FFs) in one grain from the palace (Fig. 18e). These are narrowly spaced, short, parallel-to-subparallel lamellae that typically branch off other lamellae at ~50–60° angles and form at pressures ≥7 GPa^51,58. Under crossed polars, 5 of 7 grains display mosaicism, a strongly mottled extinction pattern, and 2 of 7 grains display “undulose extinction,” wavy extinction patterns oriented perpendicular to the direction of lamellae.

The cathodoluminescence results revealed that the quartz lamellae are either non-luminescent black (indicative of amorphous quartz^59–61) or red (indicative of quartz that has crystallized, or “healed”^59–61). The unshocked body of the quartz grain typically appears blue. Further inspection of the non-luminescent lamellae using crossed polarizers on an optical microscope confirmed that material in some lamellae is isotropic, consistent with amorphous quartz⁴⁷. Tectonic lamellae, i.e., ones that develop from slow strain along fault lines, commonly luminesce in blue or red wavelengths^59,61, allowing for differentiation from impact-shocked quartz. One example from Tell el-Hammam is shown in Supporting Information, Fig. S6.

U-stage measurements show that all five quartz grains display crystallographically oriented microfractures, planar fractures (PFs), feather features (FFs), and/or planar deformation features (PDFs), all of which are characteristic of impact-related shock metamorphism^51,61. Altogether, the 7 Tell el-Hammam quartz grains/crystallites match 17 of 17 distinguishing characteristics of classic impact-shocked quartz (see Table 2), but match few characteristics of tectonically shocked quartz. We also investigated quartz grains from two samples above and below the destruction layer in both the palace and the temple and observed tectonically shocked quartz but no shock lamellae in ~2000 quartz grains from each sample.

Discussion of shocked quartz. Planar microstructures (PFs) form at relatively low shock pressures (approximately ≥5 GPa)⁴⁹ and involve only partial, localized alteration of the quartz grain. PFs are typically 5–10 µm wide and spaced 15–20 µm or more apart. Planar deformation features (PDFs) form at approximately ≥8 GPa and involve the transformation of crystalline quartz to an amorphous phase along lamellae⁵⁰. PDFs are narrow (typically <2–3 µm wide) and more closely spaced (typically 2–10 µm) than PFs, as are most lamellae in Tell el-Hammam shocked grains. PDFs are typically straight and parallel and are most commonly found in large impact craters, such as the Ries Crater in Germany and Popigai Crater in Russia⁶¹. However, at low shock pressures, PDFs may appear chaotic, subparallel, and often curved due to thermal alteration, as is evident at smaller impact sites such as Meteor Crater in Arizona and the Wabar Crater in Saudi Arabia⁴⁷.

Basal plane lamellae (0001) are common at low shock levels of >5 GPa and <10 GPa^48,49 but are rarely observed at higher impact shock levels of >10 GPa⁴⁹. Two of the 7 Tell el-Hammam shocked quartz grains/crystallites display (0001) planes, consistent with low shock conditions. At high pressures, the lamellae in shocked quartz often are very straight and parallel and extend from edge to edge of grains. However, at lower pressures, lamellae typically extend discontinuously across grains, as occurs in all five Tell el-Hammam grains, consistent with low shock conditions.

Known shocked quartz grains, when observed using optical microscopy and SEM imagery, are often decorated with lines of sub-micron-diameter bubbles. These decorations are considered to have “healed” by slow reversion of amorphous quartz to crystalline quartz (e.g., in Vredefort crater⁶¹) and the resultant exsolution of water^47,54. All shocked quartz grains at Tell el-Hammam display decorations.

In geologically old shocked quartz grains, shock lamellae are commonly discontinuous across grains and are decorated with micron-sized bubbles. However, the same result can occur from rapid, high-temperature, post-shock alteration during the impact event⁴⁷. At Tell el-Hammam, the shocked quartz grains are inferred to have resulted from low-grade shock metamorphism that rapidly healed from thermal alteration during the impact event.

Shock metamorphism by a cosmic impact is the most likely explanation, but we also considered other processes that can produce lamellae in quartz:

Shock lamellae can form during lightning strikes. However, these only form within a few microns of the grain edge, unlike impact-related shock lamellae that are found across the interior of grains. Lightning-produced lamellae also are more closely spaced (<0.33 µm) and do not form along the (0001) plane⁶², as some do at Tell el-Hammam. These three characteristics are unlike those observed at Tell el-Hammam and eliminate lightning as a likely source of Tell el-Hammam shocked quartz grains.
Non-impact deformation lamellae can be produced by tectonically induced pressures associated with faults, such as the Rift Zone near Tell el-Hammam. However, such lamellae are not oriented along the (0001) plane^53,61, and instead, they commonly vary by ±10°–30°. Tectonic forces produce slow-strain deformation that creates lamellae with the appearance of twisted ribbons but do not contain amorphous quartz^61,63. SEM analyses of HF-etched grains allow for unambiguous visual distinction between glass-filled PDFs and glass-free tectonic lamellae, which are not visible on the surface of sectioned grains^61,63. In addition, tectonic lamellae often appear blue in CL imagery and never black⁶¹. This eliminates tectonism as the source of the lamellae in all Tell el-Hammam quartz grains based on this criterion.
Several conclusive tests on these grains have enabled us to positively differentiate impact-shocked quartz from those that were tectonically shocked. (a) The lamellae in known impact-shocked grains are crystallographically aligned, as at Tell el-Hammam, but unlike tectonic grains. (b) Impact-shocked lamellae are visible in SEM imaging and with epi-illumination using optical microscopy, indicating the presence of amorphous quartz, as at Tell el-Hammam and unlike in tectonic grains. (c) Impact-shocked lamellae are often non-luminescent (black) under CL imaging, as with Tell el-Hammam grains and unlike tectonic grains.
Lamellae in quartz can be produced artificially under laboratory conditions. Most such lamellae are oriented 45° to the c axis but some are parallel. This mechanism is not relevant to Tell el-Hammam, where the sample deposits are deeply buried and sealed from potential modern contamination.
Shock lamellae can form in aboveground and underground atomic bomb blasts⁶⁴, but no atomic detonations have occurred at Tell el-Hammam.
Shocked quartz is traditionally accepted as an indicator of a hard impact with Earth’s surface, and so another possibility is a crater-forming impact, either at 1650 BCE or during a much older event. However, no shocked quartz grains were found above or below the destruction layer in the palace or the temple, making it likely that they date to 1650 BCE and unlikely that they result from an older or younger impact event. No contemporary crater has yet been identified, but a hypothetical crater of only a few tens of meters in diameter could have been created. If so, such a small crater may have been rapidly buried by wind action and/or overbank flooding from the Jordan River and thus, no longer be visible.
Finally, the most likely scenario is that the shock lamellae resulted from exposure to high pressures and high temperatures during a Tunguska-like cosmic airburst. In addition, when incoming bolides detonate at altitude, they can burst into numerous meters-wide fragments that strike the ground to form small transient craters, generating enough energy to create shocked quartz.

Based on the evidence, we conclude that Tell el-Hammam shocked quartz grains were ejected from ground zero (either under the airburst or in a crater) as distal ejecta and diluted by much higher numbers of non-shocked detrital grains. These shocked grains are a mixture of low-grade impact-related sub-planar microfractures, planar features (PFs), feather features (FFs), and planar deformation features (PDFs), most likely formed at ~5–10 GPa (50 k to 100 k standard atmospheres). Most Tell el-Hammam shocked grains have discontinuous lamellae that are partially healed due to simultaneous exposure to high pressures and high temperatures. We infer that this shock metamorphism occurred either during one or more small crater-forming impacts or airbursts within ~5–10 km of the city.

Footnotes

47. French, B. M. & Koeberl, C. (2010) The convincing identification of terrestrial meteorite impact structures: What works, what doesn’t, and why. Earth-Science Reviews 98, 123–170.

48. Langenhorst, F. (2002) Shock metamorphism of some minerals: Basic concepts and applications. Bulletin of the Czech Geological Survey 77, 265–282.

49. Stöffler, D. & Langenhorst, F. (1994) Shock metamorphism of quartz in nature and experiment: I. Basic observation and theory. Meteoritics 29, 155–181.

50. Grieve, R. A. F., Robertson, P. B. & Dence, M. R. (1981) Constraints on the formation of shock lamellae in quartz. Nature 293, 406–408.

51. Stöffler, D. (1971) Progressive shock metamorphism and classification of shock-related features in rocks and minerals. Journal of Geophysical Research 76, 5541–5551.

52. Robertson, P. B. (1975) Zones of shock metamorphism at the Charlevoix impact structure, Quebec. Geological Society of America Bulletin 86, 1630–1638.

53. Poelchau, M. H. et al. (2013) Impact-induced planar microstructures in quartz: A transmission electron microscopy study. Meteoritics & Planetary Science 48, 2187–2201.

54. Ferrière, L., Koeberl, C. & Reimold, W. U. (2009) Characterisation of planar deformation features in quartz: A combined SEM–CL study. Meteoritics & Planetary Science 44, 925–940.

55. Sadowski, G. R. & Cordeiro, H. J. (1980) ANIE program for indexing crystallographic planes in quartz. Computers & Geosciences 6, 189–198.

56. Robertson, P. B. & Grieve, R. A. F. (1977) Shock metamorphism of quartz from the Charlevoix impact structure. Canadian Journal of Earth Sciences 14, 2311–2319.

57. Goltrant, O., Cordier, P. & Doukhan, J. C. (1992) Planar deformation features in shocked quartz: A transmission electron microscopy investigation. Earth and Planetary Science Letters 113, 293–301.

58. Langenhorst, F. & Deutsch, A. (1994) Shock metamorphism of minerals: Basic concepts and application to the Tunguska event. Planetary and Space Science 42, 401–412.

59. Götte, T., Ramseyer, K. & Amthauer, G. (1999) Cathodoluminescence characterization of deformation structures in quartz. Mineralogical Magazine 63, 559–574.

60. Ramseyer, K., Baumann, J., Matter, A. & Mullis, J. (1988) Cathodoluminescence of quartz as a tool to reveal deformation structures. Journal of Sedimentary Petrology 58, 504–511.

61. Ferrière, L. & Osinski, G. R. (2013) Shock metamorphism. In Impact Cratering: Processes and Products, pp. 106–124. Wiley-Blackwell.

62. Elmi, C., Chen, M. & Elmi, M. (2017) Lightning-induced shock lamellae in quartz. Scientific Reports 7, 17880.

63. Trepmann, C. A. & Stöckhert, B. (2003) Microstructures of experimentally deformed quartz single crystals. Journal of Structural Geology 25, 1405–1421.

64. Eby, G. N. et al. (2010) Shocked quartz at the Trinity nuclear test site. Meteoritics & Planetary Science 45, 1431–1443.

65. Svetsov, V. V. (2007) Tunguska cosmic body of 1908: Is it from the asteroid belt? Solar System Research 41, 509–517.

66. Adamsky, V. B. & Smirnov, Y. N. (1994) Nuclear testing in Kazakhstan: The Soviet nuclear testing program. Nuclear Weapons Journal 3, 45–56.

67. Dolgov, Y. A. et al. (1973) Shocked quartz from the Tunguska region. Meteoritics 8, 83–89.

68. Carter, N. L. et al. (1968) Deformation of quartz in the Trinity test. Journal of Geophysical Research 73, 3635–3648.

69. Kletetschka, G., Wasilewski, P. & Taylor, P. T. (2000) Magnetic evidence for impact-induced shock metamorphism in sediments. Earth and Planetary Science Letters 181, 393–402.

Shocked quartz grains from known airbursts

from Bunch et al. (2021:25-27)

We also conducted investigations on three other airburst events to better understand the proposed Tell el-Hammam cosmic impact event. The first event, the Tunguska cosmic airburst, occurred above Siberia in 1908⁶⁵, estimated at ~10–30 megatons of TNT equivalent at an altitude of 5–15 km. Second, the Trinity atomic bomb was detonated at an altitude of 40 m in New Mexico in 1945⁶⁴, estimated at 22 kilotons of TNT equivalent. Third, two Russian atomic bombs were detonated at an identical location in Kazakhstan. Joe-1 (RDS-1) in 1949 is estimated at 20 kilotons TNT equivalent at 30 m elevation⁶⁶, and Joe-4 (RDS-6) in 1953 is estimated at 400 kilotons at an altitude of 400 m⁶⁶. Samples included an undifferentiated mix of materials from both detonations.

We searched for potential shock lamellae in grains in ~2000 thin-sectioned quartz grains from each of the three sites and observed approximately 1 shocked quartz grain per 500–1000 grains, similar to the results for Tell el-Hammam. At all three sites, a small number of shocked quartz grains appear to have been ejected from ground zero and mixed with numerous unshocked detrital grains. As with impact-related PDFs, the lamellae commonly appear as one or more sets that are closely spaced (2–10 µm), narrow (< 2 µm), and range from curved to straight and parallel to subparallel (Fig. 21). The lamellae in grains from all of these sites match 17 features of impact-shocked quartz (Table 2). Most importantly, the Tell el-Hammam grains pass four main tests that confirm impact-shocked lamellae and contra-indicate tectonic lamellae: (i) they are crystallographically aligned; (ii) some are parallel to the c axis; (iii) all are visible in SEM imaging and epi-illumination, indicating the presence of amorphous quartz; and (iv) all are non-luminescent (black) or red under CL imaging.

Discussion of shocked quartz in airbursts. In a previous study, shocked quartz was reported at Tunguska a few miles from ground zero⁶⁷ but has been disputed⁵⁸. To our knowledge, this is the first study to report shocked quartz at the site of the Joe-1/4 detonations. In addition, it has been reported at the Trinity site^64,68, where Eby et al.⁶⁴ concluded that Trinity shocked quartz had been exposed to pressures of at least 8 GPa and temperatures of >1600 °C for a duration of 14–20 s with a maximum fireball temperature of >8400° K for ~3 s.

A previous hypothesis explains how shock lamellae might form in a cosmic airburst, such as Tunguska. Kletetschka et al.⁶⁹ proposed that when unconsolidated surface sediments containing quartz grains are struck by the atmospheric shock wave from an airburst, if the velocity exceeds 7 km/s, the elastic limit of quartz, then shock lamellae develop. Quartz grains in surface sediments typically are only minimally shocked, often with only one set of lamellae.

The Trinity detonation at an altitude of ~40 m above the surface was much lower than for Tunguska. In addition, the energy released was less than for a Tunguska-class event, but even so, it produced shocked quartz. For Joe-1/4, the detonation altitude of 400 m was lower than for Tunguska and the energy yield was less, but shocked quartz also was produced. These atomic tests support an important finding of this investigation and previous ones^64,67: shock metamorphism can occur during an airburst in the absence of a ground impact, rather than, as is commonly accepted, only during ground impacts of sufficient magnitude to form a crater. Our evidence suggests that the lamellae observed in Tell el-Hammam quartz formed during a cosmic airburst under conditions similar to those during the Tunguska airburst and the aerial atomic detonations.

Footnotes

64. Eby, G. N. et al. (2010) Shocked quartz at the Trinity nuclear test site. Meteoritics & Planetary Science 45, 1431–1443.

65. Svetsov, V. V. (2007) Tunguska cosmic body of 1908: Is it from the asteroid belt? Solar System Research 41, 509–517.

66. Adamsky, V. B. & Smirnov, Y. N. (1994) Nuclear testing in Kazakhstan: The Soviet nuclear testing program. Nuclear Weapons Journal 3, 45–56.

67. Dolgov, Y. A. et al. (1973) Shocked quartz from the Tunguska region. Meteoritics 8, 83–89.

68. Carter, N. L. et al. (1968) Deformation of quartz in the Trinity test. Journal of Geophysical Research 73, 3635–3648.

69. Kletetschka, G., Wasilewski, P. & Taylor, P. T. (2000) Magnetic evidence for impact-induced shock metamorphism in sediments. Earth and Planetary Science Letters 181, 393–402.

High‑temperature melted minerals

Melted quartz grains

from Bunch et al. (2021:27-28)

Crystalline quartz melts between 1670 °C (tridymite) and 1713 °C (cristobalite), and because quartz is pervasive and easily identified, melted grains serve as an important temperature indicator. At Tell el-Hammam, we observed that unmelted potsherds displayed no melted quartz grains, indicating exposure to low temperatures. On the other hand, most quartz grains on the surfaces of pottery, mudbricks, and roofing clay exhibited some degree of melting, and unmelted quartz grains were rare. Nearly all quartz grains found on broken, unmelted surfaces of potsherds were also unmelted. On melted pottery and mudbricks, melted quartz has an estimated density of 1 grain per 5 mm².

Melted quartz grains at Tell el-Hammam exhibit a wide range of morphologies. Some show evidence of partial melting that only melted grain edges and not the rest of the grain (Figs. 22, 23). Others displayed nearly complete melting with diffusion into the melted Ca–Al–Si matrix of pottery or mudbrick (Fig. 22). Melted quartz grains commonly exhibit vesiculation caused by outgassing (Figs. 22, 23), suggesting that those grains rose above quartz’s melting point of ~1713 °C.

An SEM–EDS elemental map of one melted grain showed that the quartz had begun to dissociate into elemental Si (Fig. 22b). Another grain (Fig. 23c–e) displayed flow marks consistent with exposure to temperatures above 1713 °C where the viscosity of quartz falls low enough for it to flow easily. Another SEM–EDS analysis confirmed that one agglutinated mass of material is 100 wt.% SiO₂ (Fig. 23f, g), suggesting that this polycrystalline quartz grain shattered, melted, and partially fused again.

Discussion of melted quartz. Moore et al.¹⁷ reported that during heating experiments, many quartz grains < 50-µm-wide exhibited partial melting at as low as 1300 °C, but larger grains >50-µm-wide remained visually unaltered up to ~1700 °C. By 1850 °C, all quartz grains fully melted. These experiments establish a particle-size dependency and confirm the melting point for >50-µm-wide Tell el-Hammam quartz grains between ~1700–1850 °C. Melted >50-µm-wide quartz grains on the surfaces of melted pottery and mudbrick from the Tell el-Hammam destruction layer indicate exposure to these unusually high temperatures >1700 °C.

Previously, Thy et al.⁷⁰ proposed that glass at Abu Hureyra did not form during a cosmic impact, but rather, formed in biomass slag that resulted from thatched hut fires. However, Thy et al. did not determine whether or not high-temperature grains existed in the biomass slag. To test that claim, Moore et al.¹⁷ analyzed biomass slag from Africa and found only low-temperature melted grains with melting points of ~1200 °C, consistent with a temperature range for biomass slag of 1155–1290 °C, as reported by Thy et al.⁷¹. Upon testing the purported impact glass from Abu Hureyra, Moore et al.¹⁷ discovered high-temperature mineral grains that melt in the range of 1713° to >2000 °C, as are also found in Tell el-Hammam glass. These test results suggest that the melted glass from Abu Hureyra must have been exposed to higher temperatures than those associated with fires in thatched huts.

Because of the presence of high-temperature minerals at Tell el-Hammam, we conclude that, as at Abu Hureyra, the meltglass could not have formed simply by burning thatched huts or wood-roofed, mudbrick buildings.

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

70. Thy, P., Willcox, G., Barfod, G. H. & Fuller, D. Q. (2015) Anthropogenic origin of siliceous scoria droplets from Pleistocene and Holocene archaeological sites in northern Syria. Journal of Archaeological Science 54, 193–209.

71. Thy, P., Segobye, A. K. & Ming, D. W. (1995) Implications of prehistoric glassy biomass slag from east-central Botswana. Journal of Archaeological Science 22, 629–637.

Melted Fe‑ and Si‑rich spherules

from Bunch et al. (2021:28-30)

The presence of melted spherulitic objects (“spherules”) has commonly been used to help identify and investigate high-temperature airburst/impact events in the sedimentary record. Although these objects are referred to here as “spherules,” they display a wide range of other impact-related morphologies that include rounded, sub-rounded, ovate, oblate, elongated, teardrop, dumbbell, and/or broken forms^17,72–82. Optical microscopy and SEM–EDS are commonly used to identify and analyze spherules and the processes by which they are formed. Care is needed to conclusively distinguish high-temperature spherules produced by cosmic impacts from other superficially similar forms. Other such objects that frequently occur in sediments include anthropogenic spherules (typically from modern coal-fired power plants), authigenic framboids (Supporting Information, Fig. S7), rounded detrital magnetite, and volcanic spherules.

Spherules in Tell el-Hammam sediment were investigated from stratigraphic sequences that include the MB II destruction layer at four locations: palace, temple, ring road, and wadi (Fig. 24). For the palace (Field UA, Square 7GG), the sequence spanned 28 cm with 5 contiguous samples of sediment ranging from 3-cm thick for the MB II destruction layer to 13-cm thick for some outlying samples. In the palace, 310 spherules/kg (Fig. 24d) were observed in the destruction layer with none found in samples above and below this layer. For the temple (Field LS, Square 42J), 5 continuous samples spanned 43 cm and ranged in thickness from 6 to 16 cm; the MB II layer contained ~2345 Fe- and Si-rich spherules/kg with 782/kg in the sample immediately below and none at other levels (Fig. 24c). Six contiguous samples from the ring road (Field LA, Square 28 M) spanned 30 cm with all 5 cm thick; the MB II destruction layer at this location contains 2150 spherules/kg with none detected in younger or older samples (Fig. 24b). Five discontinuous samples from the wadi spanned 170 cm, ranging from 10-cm thick for the destruction layer up to 20-cm thick for other samples; the MB II destruction layer at this location contained 2780 spherules/kg with none in samples from other levels (Fig. 24a, Supporting Information, Table S3). Notably, when melted mudbrick from the ring road was being mounted for SEM analysis, numerous loose spherules were observed within vesicles of the sample, confirming a close association between the spherules and meltglass. At all four locations, the peaks in high-temperature spherule abundances occur in the MB II destruction layer dating to ~1650 BCE.

SEM images of spherules are shown in Figs. 25, 26, 27 and 28, and compositions are listed in Supporting Information, Table S4. The average spherule diameter was 40.5 µm with a range of 7 to 72 µm. The dominant minerals were Fe oxides averaging 40.2 wt.%, with a range of up to 84.1 wt.%; elemental Fe with a range of up to 80.3 wt.%; SiO₂ averaging 20.9 wt.%, ranging from 1.0 to 45.2 wt.%; Al₂O₃ averaging 7.8 wt.% with a range of up to 15.6 wt.%; and TiO₂ averaging 7.1 wt.% with a range of up to 53.1 wt.%. Fourteen spherules had compositions >48 wt.% of oxidized Fe, elemental Fe, and TiO₂; five spherules contained < 48 wt.% Fe and Ti; and two had >75 wt.% Fe with no Ti. Eight of 23 spherules analyzed contained detectable levels of Ti at up to 53.1 wt.%.

Two unusual spherules from the palace contain anomalously high percentages of rare-earth elements (REEs) at >37 wt.% of combined lanthanum (La) and cerium (Ce) (Fig. 26), as determined by preliminary measurements using SEM–EDS. Minor oxides account for the rest of the spherules’ bulk composition (Table S1).

One 54-µm-wide sectioned spherule contains titanium sulfide (TiS) with a melting point of ~1780 °C. TiS, known as wassonite, was first identified in meteorites (Fig. 27) and has been reported in impact-related material^17,81,83. However, TiS sometimes occurs as an exsolution product forming fine networks in magnetite and ilmenite and can be of terrestrial origin.

One unusual piece of 167-µm-wide Ca–Al–Si meltglass contains nearly two dozen iron oxide spherules on its surface (Fig. 28). The meltglass contains a completely melted quartz grain as part of the matrix (Fig. 28b). Most of the spherules appear to have been flattened or crushed by collision with the meltglass while they were still partially molten (Fig. 28c).

Discussion of spherules and meltglass. Melted materials from non-impact-related combustion have been reported in multiple studies. Consequently, we investigated whether Ca-, Fe-, and Si-rich spherules and meltglass (mudbrick, pottery, plaster, and roofing clay) may have formed normally, rather than from a cosmic impact event. For example

glassy spherules and meltglass are known to form when carbon-rich biomass smolders below ground at ~1000° to 1300 °C, such as in midden mounds⁷¹. They also form in buried peat deposits⁸⁴, underground coal seams⁸⁵, burned haystacks⁸⁶, and in large bonfires, such as at the Native American site at Cahokia, Illinois, in the USA⁸⁷

Also, ancient fortifications (hillforts) in Scotland and Sweden, dating from ~1000 BCE to 1400 AD, have artificially vitrified walls that melted at temperatures of ~850° to 1000 °C⁸⁸

Partially vitrified pottery and meltglass derived from the melting of wattle and daub (thatch and clay) with estimated temperatures of ~1000 °C have been reported in burned houses of the Trypillia culture in Ukraine^89,90

Vitrified mudbricks and pottery that melted at < 1100 °C have been reported at Sardis, Turkey, dating to the seventh and sixth centuries BCE ⁹¹; in the northern Jordan Valley at an Early-Bronze-Age site called Tell Abu al-Kharaz⁹²; and at Early-Bronze-Age Tell Chuera in Syria⁹³. All these sites describe melting temperatures ranging from ~850° to 1300 °C

In another example of meltglass, vitrified bricks at Tell Leilan in Syria, dating to ~2850 to 2200 BCE, are estimated by Weiss⁹⁴ to have melted at ~1200 °C, and he attributed high-calcium spherules to low-temperature combustion of thatch roofing materials⁹⁵. However, thatch has low calcium content, leading Courty⁹⁶ to propose that this material formed from melted lime-based plaster during an airburst/impact at Tell Leilan ~550 years before the destruction of Tell el-Hammam. Courty⁹⁶ reported aluminosilicate spherules with unusual high-temperature elemental nickel (melting point: ~1455 °C); complex vesicular glass particles that contain terrestrially rare unoxidized nickel inclusions; and both single and multiple calcite spherules (melting point =1500 °C, as measured by experiments in this contribution).

For the melted materials, there is a definitive difference: high-temperature minerals are embedded in meltglass at Tell el-Hammam but none are present at these other sites (except for Tell Leilan). To explore this difference, Moore et al.¹⁷ investigated biomass glass from midden mounds in Africa and found no high-temperature minerals. For this contribution, we used SEM–EDS to examine aluminosilicate meltglass from an underground peat fire in South Carolina, USA; meltglass in coal-fired fly ash from New Jersey, USA; and mining slag from a copper mine in Arizona, USA. All these meltglass examples display unmelted quartz and contain no other high-temperature melted grains, consistent with low-temperature melting at < 1300 °C.

At the sites with non-impact meltglass, estimated temperatures were consistently less than 1300 °C, too low to melt magnetite into Fe-rich spherules, e.g., with compositions of >97 wt.% FeO, as are found at Tell el-Hammam. Nor can these low temperatures produce meltglass and spherules embedded with melted zircon (melting point =1687 °C), chromite (2190 °C), quartz (1713 °C), platinum (1768 °C), and iridium (2466 °C). Moore et al.¹⁷ confirmed that the melting of these high-temperature minerals requires minimum temperatures of ~1500° to 2500 °C.

This evidence demonstrates that although the matrix of the spherules and meltglass at Tell el-Hammam likely experienced incipient melting at temperatures lower than ~1300 °C, this value represents only the minimum temperature of exposure, because the high-temperature minerals embedded in them do not melt at such low temperatures. Instead, the spherules and meltglass at Tell el-Hammam must have reached temperatures greater than ~1300 °C, most likely involving brief exposure to ambient temperatures of ~2500 °C, the melting point of iridium. These temperatures far exceed those characteristic of city fires and other types of biomass burning. In summary, all of this evidence is consistent with very high temperatures known during cosmic impacts but inconsistent with other known natural causes.

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

71. Thy, P., Segobye, A. K. & Ming, D. W. (1995) Implications of prehistoric glassy biomass slag from east-central Botswana. Journal of Archaeological Science 22, 629–637.

72. Firestone, R. B. et al. (2007) Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Sciences 104, 16016–16021.

73. Firestone, R. B. et al. (2010) Analysis of the Younger Dryas impact layer. Journal of Siberian Federal University 1, 30–62.

74. Hagstrum, J. T., Firestone, R. B., West, A., Weaver, J. C. & Bunch, T. E. (2017) Impact-related microspherules in Late Pleistocene Alaskan and Yukon “muck” deposits signify recurrent episodes of catastrophic emplacement. Scientific Reports 7, 1–15. https://doi.org/10.1038/s41598-017-16958-2

75. Israde-Alcántara, I. et al. (2012) Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis. Proceedings of the National Academy of Sciences 109, E738–E747.

76. LeCompte, M. A. et al. (2012) Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis. Proceedings of the National Academy of Sciences 109, E2960–E2969.

77. LeCompte, M. A. et al. (2017) The Bowser Road Mastodon and the Younger Dryas Impact Hypothesis, Appendix 3 in The archaeological recovery of the Bowser Road Mastodon, Orange County NY (ed. R. M. Gramly). Persimmon Press.

78. Pino, M. et al. (2019) Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka. Scientific Reports 9, 4413.

79. Teller, J. et al. (2019) A multi-proxy study of changing environmental conditions in a Younger Dryas sequence in southwestern Manitoba, Canada, and evidence for an extraterrestrial event. Quaternary Research 93, 1–28.

80. Wu, Y., Sharma, M., LeCompte, M. A., Demitroff, M. N. & Landis, J. D. (2013) Origin and provenance of spherules and magnetic grains at the Younger Dryas boundary. Proceedings of the National Academy of Sciences 110, E3557–E3566.

81. Bunch, T. E. et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

82. Wittke, J. H. et al. (2013) Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. Proceedings of the National Academy of Sciences 110, E2088–E2097.

83. Harris, R. & Schultz, P. (2019) Are Ti-Rich particles in Late Pleistocene sediments from Patagonia distal ejecta from an Atacama airburst? In Lunar and Planetary Science Conference, abstract 2526.

84. Baker, G. A. (1959) Tektites. National Museum of Victoria.

85. Sharygin, V., Sokol, E. & Belakovskii, D. (2009) Fayalite-sekaninaite paralava from the Ravat coal fire (central Tajikistan). Russian Geology and Geophysics 50, 703–721.

86. Baker, G. (1968) Micro-forms of hay-silica glass and of volcanic glass. Mineralogical Magazine 36, 1012–1023.

87. Pauketat, T. R. et al. (2002) The residues of feasting and public ritual at early Cahokia. American Antiquity 67, 257–279.

88. Friend, C., Dye, J. & Fowler, M. (2007) New field and geochemical evidence from vitrified forts in South Morar and Moidart, NW Scotland: further insight into melting and the process of vitrification. Journal of Archaeological Science 34, 1685–1701.

89. Johnston, S. et al. (2018) The experimental building, burning and excavation of a two-storey Trypillia house. PAST: Newsletter of the Prehistoric Society 89, 13–15.

90. Orton, D. C., Nottingham, J., Rainsford-Betts, G., Hosking, K. & Millard, A. (2020) Animal bones [from Nebelivka]. In Early Urbanism in Europe (ed. G. Bisserka), 383–404. De Gruyter Open.

91. Dever, W. G. (1996) Preliminary Excavation Reports: Sardis, Idalion, and Tell El-Handaquq North, Vol. 53. American Schools of Oriental Research.

92. Bikai, P. M. & Egan, V. (1996) Archaeology in Jordan. American Journal of Archaeology 100, 507–535.

93. Yates, C. J. C. (2014) Beyond the mound: Locating complexity in Northern Mesopotamia during the “Second Urban Revolution”. Boston University.

94. Senior, L. M. (1998) Time and technological change: Ceramic production, labor, and economic transformation in a third millennium complex society (Tell Leilan, Syria). University of Arizona.

95. Weiss, H. et al. (n.d.) Revising the contours of history at Tell Leilan. Annales Archéologiques Arabes Syriennes 59.

96. Courty, M.-A. (n.d.) The soil record of an exceptional event at 4000 BP in the Middle East. In Natural Catastrophes During Bronze Age Civilisations, p. 93.

Calcium carbonate spherules and plaster

from Bunch et al. (2021:30-33)

In sediments of the destruction layer, we observed amber-to-off-white-colored spherules (Fig. 29) at high concentrations of ~240,000/kg in the palace, ~420/kg in the temple, ~60/kg on the ring road, and ~910/kg in the wadi (Supporting Information, Table S2). In all four profiles, the spherules peak in the destruction layer with few to none above or below. Peak abundances of calcium carbonate spherules are closely associated with peak abundances of plaster fragments, which are the same color.

By far the most spherules (~250× more) occurred in the destruction layer of the palace, where excavations showed that nearly every room and ceiling was surfaced with off-white lime-based plaster. Excavators uncovered high-quality lime plaster fragments still adhering to mudbricks inside the MB II palace complex, and in one palace room, we uncovered fragments of melted plaster (Fig. 29e). In contrast, lime plaster was very rarely used in buildings on the lower tall, including those near the temple.

To explore a potential connection between plaster and spherules, we performed SEM–EDS on samples of the palace plaster. Comparison of SEM–EDS analyses shows that the plaster composition has a >96% similarity to the spherule composition: CaCO₃ =71.4 wt.% in plaster versus 68.7 wt.% in the spherules; elemental C =23.6 versus 26.3 wt.%; SiO₂ =2.4 versus 1.8 wt.%; MgO =1.7 versus 2.0 wt.%; and SO₃ =0.94 versus 1.2 wt.%. The high carbon percentage and low sulfur content indicate that the plaster was made from calcium carbonate and not gypsum (CaSO₄·2H₂O). SEM imaging revealed that the plaster contains small plant parts, commonly used in plaster as a binder, and is likely the source of the high abundance of elemental C in the plaster. Inspection showed no evidence of microfossils, such as coccoliths, brachiopods, and foraminifera. The morphology of the spherules indicates that they are not authigenic or biological in origin.

Discussion of carbonate plaster and spherules. One of the earliest known uses of CaCO₃-based plaster was in ~6750 BCE at Ayn Ghazal, ~35 km from Tell el-Hammam in modern-day Amman, Jordan⁹⁷. At that site, multi-purpose lime plaster was used to make statues and figurines and to coat the interior walls of buildings. Because the production of lime-based plaster occurred at least 3000 years before Tell el-Hammam was destroyed, the inhabitants of Tell el-Hammam undoubtedly were familiar with the process. Typically, lime powder was produced in ancient times by stacking wood/combustibles interspersed with limestone rocks and then setting the stack on fire. Temperatures of ~800–1100 °C were required to transform the rocks into crumbly chalk, which was then mixed with water to make hydrated lime and plastered onto mudbrick walls ⁹⁷.

At Tell el-Hammam, fragments of CaCO₃-based plaster are intermixed in covarying abundances with CaCO₃-based spherules with both compositions matching to within 96%. This similarity suggests that the carbonate spherules are derived from the plaster. We infer that the high-temperature blast wave from the impact event stripped some plaster from the interior walls of the palace and melted some into spherules. However, it is difficult to directly melt CaCO₃, which gives off CO₂ at high temperatures and decomposes into lime powder. We investigated this cycle in a heating experiment with an oxygen/propylene torch and found that we could decompose the plaster at ~1500 °C, the upper limit of the heating test, and begin incipient melting of the plaster. The heated plaster produced emergent droplets at that temperature but did not transform into free spherules (Supporting Information, Text S2).

Similar spherules have been reported from Meteor Crater, where spherules up to ~200 μm in diameter are composed entirely of CaCO₃ formed from a cosmic impact into limestone ^98,99. One of several possible hypotheses for Tell el-Hammam is that during the impact event, the limestone plaster converted to CaO with an equilibrium melting point of 2572 °C. However, it is highly likely that airborne contaminants, such as sodium and water vapor, reacted with the CaO and significantly lowered the melting point, allowing spherule formation at ≥1500 °C.

The proposed chemical sequence of events of plaster formation and the later impact are as follows:

Limestone was heated to ~800–1100 °C, decomposing to quicklime.
CaCO₃ → CaO + CO₂

Quicklime was mixed with water to make a wet plaster. CaO + H₂O → Ca(OH)₂

The plaster hardened and slowly absorbed CO₂ to revert to CaCO₃. Ca(OH)₂ + CO₂ → H₂O + CaCO₃

The high-temperature impact event melted some plaster into spherules. CaCO₃ → CaO (spherules) + CO₂ (<1500 °C)

CaO spherules slowly absorbed CO₂ to revert to CaCO₃ as spherules. Ca + CO₂ → CaCO₃ (as spherules)

General discussion of all spherules. According to the previous investigations^17,72,81,82, Fe-rich spherules such as those found at Tell el-Hammam typically melt at >1538 °C, the melting point of iron (Table 1). Because of the presence of magnetite (Fe₃O₄) in the REE spherule, its melting point is inferred to be >1590 °C (Table 1). The Si-rich spherules are similar in composition to Tell el-Hammam sediment and mudbrick, and thus, we propose that they were derived from the melting of these materials at >1250 °C. The carbonate-rich spherules likely formed at >1500 °C.

Several studies describe a mechanism by which spherules could form during a low-altitude cosmic airburst ^100,101. When a bolide enters Earth’s atmosphere, it is subjected to immense aerodynamic drag and ablation, causing most of the object to fragment into a high-temperature fireball, after which its remaining mass is converted into a high-temperature vapor jet that continues at hypervelocity down to the Earth’s surface. Depending on the altitude of the bolide’s disruption, this jet is capable of excavating unconsolidated surficial sediments, melting them, and ejecting the molten material into the air as Si- and Fe-rich spherules and meltglass. This melted material typically contains a very low percentage (LT1 wt.%) of impactor material¹⁰².

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

72. Firestone, R. B. et al. (2007) Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Sciences 104, 16016–16021.

81. Bunch, T. E. et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

82. Wittke, J. H. et al. (2013) Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. Proceedings of the National Academy of Sciences 110, E2088–E2097.

97. Grissom, C. A. (1996) Conservation of Neolithic lime plaster statues from ’Ain Ghazal. Studies in Conservation 41, 70–75. https://doi.org/10.1179/sic.1996.41.Supplement-1.70

98. Osinski, G., Bunch, T. & Wittke, J. (2003) Evidence for the shock melting of carbonates from Meteor Crater, Arizona. Meteoritics & Planetary Science Supplement 38, abstract 5070.

99. Osinski, G., Bunch, T. & Wittke, J. (2007) Impact melt generation at Meteor Crater, Arizona: Implications for impacts into volatile-rich target rocks. Meteoritics & Planetary Science Supplement 42, abstract 5110.

100. Boslough, M. et al. (2012) Arguments and evidence against a Younger Dryas impact event. In Climates, Landscapes, Civilizations, Geophysical Monograph Series Vol. 198, 13–26. American Geophysical Union.

101. Boslough, M. & Crawford, D. A. (2008) Low-altitude airbursts and the impact threat. International Journal of Impact Engineering 35, 1441–1448.

102. Wakita, S., Johnson, B. C., Denton, C. A. & Davison, T. M. (2021) Jetting during oblique impacts of spherical impactors. Icarus 360, 114365.

Melted zircon grains

from Bunch et al. (2021:34-36)

To more accurately determine the maximum temperatures of the destruction layer, we used SEM–EDS to comprehensively investigate melted minerals on the outer surfaces of melted pottery and mudbricks. We searched for and analyzed zircon (melting point: ~1687 °C), chromite (~2190 °C), and quartz (~1713 °C)¹⁷.

Melted zircons in pottery and mudbricks were observed (Fig. 30) at an estimated density of 1 grain per 20 mm². On highly melted surfaces, nearly all zircons showed some degree of melting. In contrast, nearly all zircons found on broken interior surfaces were unmelted (Fig. 30d), except those within ~1 mm of melted surfaces. This implies that the temperature of the surrounding atmosphere was higher than the internal temperatures of the melting objects. Unmelted potsherds displayed only unmelted minerals.

The melted zircons in Tell el-Hammam materials exhibit a wide range of morphologies. Most showed evidence of sufficient melting to alter or destroy the original distinctive, euhedral shape of the grains. Also, the grains were often decorated with vesicles that were associated with fractures (Fig. 30a, c). Stoichiometric zircon contains 67.2 wt.% and 32.8 wt.% ZrO₂ and SiO₂ respectively, but in several Tell el-Hammam samples, we observed a reduction in the SiO₂ concentration due to a loss of volatile SiO from the dissociation of SiO₂. This alteration has been found to occur at 1676 °C, slightly below zircon’s melting point of 1687 °C¹⁰³. This zircon dissociation leads to varying ZrO₂:SiO₂ ratios and to the formation of distinctive granular textures of pure ZrO₂, also known as baddeleyite¹⁰⁴ (Figs. 30, 31, 32). With increasing time at temperature, zircon will eventually convert partially or completely to ZrO₂. Nearly all zircons observed on the surfaces of melted materials were either melted or showed some conversion to baddeleyite. We observed one zircon grain (Fig. 32d–e) displaying granular ZrO₂ associated with three phases that span a wide range of SiO₂ concentrations, likely formed at temperatures above 1687 °C. This extreme temperature and competing loss of SiO over an inferred duration of only several seconds led to complex microstructures, where grains melted, outgassed, and diffused into the surrounding matrix.

Discussion of melted zircon. Zircon grains have a theoretical, equilibrium melting point of ~1687 °C. Under laboratory heating¹⁷, zircon grains showed no detectable alteration in shape at ~1300 °C but displayed incipient melting of grain edges and dissociation to baddeleyite beginning at ~1400 °C with increasing dissociation to 1500 °C¹⁷. Most zircon grains < 50 µm completely melted at a temperature of ~1500 °C, while at ~1700 °C, the shapes of zircon grains >120 µm were still recognizable but displayed considerable melting¹⁷. These experiments establish a lower melting range for Tell el-Hammam zircon grains of ~1400° to 1500 °C.

Patterson¹⁰⁵ showed that zircon dissociation becomes favorable above 1538 °C and particles between 1 and 100 µm in size melted and dissociated when passing through a plasma, forming spherules with various amounts of SiO₂ glass containing ZrO₂ crystallites ranging in size from 5 nm to 1 µm. The majority of zircon crystals were monoclinic, but tetragonal ZrO₂ was observed for the smaller crystallite sizes. Residence times were in the order of 100 ms, and the specific ZrO₂ to SiO₂ ratio within each spherule depended on the particle’s time at temperature¹⁰⁶.

Bohor et al.¹⁰⁴ presented images of impact-shocked zircons from the K–Pg impact event at 66 Ma that are morphologically indistinguishable from those at Tell el-Hammam. Decorated zircon grains are uncommon in nature but commonly associated with cosmic impact events, as evidenced by two partially melted zircons from the known airburst/ impact at Dakhleh Oasis, Egypt (Fig. 30e). The presence of bubbles indicates that temperatures reached at least 1676 °C, where the zircon began to dissociate and outgas. Similar dissociated zircon grains also have been found in tektite glass and distal fallback ejecta (deposited from hot vapor clouds). Granular baddeleyite-zircon has been found in the ~150-km-wide K–Pg impact crater ¹⁰⁷ and the 28-km-wide Mistatin Lake crater in Canada ¹⁰⁷. The dissociation of zircon requires high temperatures of ~1676 °C¹⁰⁴, implying that Tell el-Hammam was exposed to similar extreme conditions.

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

103. Butterman, W. C. & Foster, W. R. (1967) Zircon stability and the ZrO₂–SiO₂ phase diagram. American Mineralogist 52, 880–885.

104. Bohor, B., Betterton, W. & Krogh, T. (1993) Impact-shocked zircons: discovery of shock-induced textures reflecting increasing degrees of shock metamorphism. Earth and Planetary Science Letters 119, 419–424.

105. Patterson, M. C. L. (1986) Development of a coalesced arc plasma reactor for minerals processing. University of Cambridge.

106. Rochow, E. G. (2013) The Chemistry of Silicon. Pergamon International Library of Science, Technology, Engineering and Social Studies, Vol. 9. Elsevier.

107. Glass, B. P. & Simonson, B. M. (2013) Mesozoic spherule/impact ejecta layers. In Distal Impact Ejecta Layers, 245–320. Springer.

Melted chromite grains

from Bunch et al. (2021:36)

Examples of melted chromite, another mineral that melts at high temperatures, were also observed. Thermally-altered chromite grains were observed in melted pottery, melted mudbricks, and melted roofing clay from the palace. Their estimated density was 1 grain per 100 mm2, making them rarer than melted zircon grains. The morphologies of chromite grains range from thermally altered (Fig. 33a) to fully melted (Fig. 33b, d). One chromite grain from the palace displays unusual octahedral cleavage or shock-induced planar fractures (Fig. 33b). The typical chemical composition for chromite is 25.0 wt.% Fe, 28.6 wt.% O, and 46.5 wt.% Cr, although the Cr content can vary from low values to ~68 wt.%. SEM images reveal that, as chromite grains melted, some Cr-rich molten material migrated into and mixed with the host melt, causing an increase in Cr and Fe, and corresponding depletion of Si. The ratio of Cr to Fe in chromite affects its equilibrium melting point, which varies from ~1590 °C for a negligible amount of Cr up to ~2265 °C for ~46.5 wt.% Cr as in chromite or chromian magnetite ((Fe)Cr2O4), placing the melting point of Tall el-Hammam chromite at close to 2265 °C.

Discussion of melted chromite. Chromite grains theoretically melt at ~2190 °C. Moore et al.¹⁷ reported the results of heating experiments in which chromite grains in bulk sediment showed almost no thermal alteration up to ~1500 °C (Supporting Information, Fig. S8). At temperatures of ~1600 °C and ~1700 °C, the shapes of chromite grains were intact but exhibited limited melting of grain edges. These results establish a range of ~1600° to 1700 °C for melting chromite grains.

Because chromite typically does not exhibit cleavage, the grain exhibiting this feature is highly unusual. Its origin is unclear but there are several possibilities. The cleavage may have resulted from exsolution while cooling in the source magma. Alternately, the lamellae may have resulted from mechanical shock during a cosmic impact, under the same conditions that produced the shocked quartz, as reported by Chen et al.¹⁰⁸ for meteorites shocked at pressures of ~12 GPa. Or they may have been formed by thermal shock, i.e., rapid thermal loading followed by rapid quenching. This latter suggestion is supported by the observation that the outside glass coating on the potsherd does not exhibit any quench crystals, implying that the cooling progressed very rapidly from liquid state to solid state (glass). This is rare in terrestrial events except for some varieties of obsidian, but common in melted material produced by atomic detonations (trinitite), lightning strikes (fulgurites), and cosmic airburst/ impacts (meltglass)⁸¹. More investigations are needed to determine the origin of the potentially shocked chromite.

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

81. Bunch, T. E. et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

108. Chen, M., Shu, J., Mao, H.-K., Xie, X. & Hemley, R. J. (2003) Natural occurrence and synthesis of two new postspinel polymorphs of chromite. Proceedings of the National Academy of Sciences 100, 14651–14654.

Nuggets of Ir, Pt, Ru, Ni, Ag, Au, Cr, and Cu in meltglass

from Bunch et al. (2021:36-40)

Using SEM–EDS, we investigated abundances and potential origins (terrestrial versus extraterrestrial) of platinum-group elements (PGEs) embedded in Tell el-Hammam meltglass, in addition to Ni, Au, and Ag. Samples studied include melted pottery (n=3); melted mudbrick (n=6); melted roofing clay (n=1), and melted lime-based building plaster (n=1). On the surfaces of all four types of meltglass, we observed melted metal-rich nuggets and irregularly shaped metallic splatter, some with high concentrations of PGEs (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt)) and some nuggets enriched in silver (Ag), gold (Au), chromium (Cr), copper (Cu), and nickel (Ni) with no PGEs (Figs. 34, 35). Importantly, these metal-rich nuggets were observed only on the top surfaces of meltglass and not inside vesicles or on broken interior surfaces.

Using SEM–EDS, we identified variable concentrations and assemblages of PGEs. The metallic particles appear to have melted at high temperatures based on the minimum melting points of the elements: iridium at 2466 °C; platinum=1768 °C; and ruthenium=2334 °C, indicating a temperature range of between approximately 1768° and 2466 °C. Our investigations also identified two PGE groups, one with nuggets in which Pt dominates Fe and the other with metallic splatter in which Fe dominates Pt.

Pt-dominant nuggets. We conducted 21 measurements on Pt-dominant Tell el-Hammam nuggets on meltglass (Fig. 34a–c). The nuggets average ~5 µm in length (range 1–12 µm) with an estimated concentration of 1 nugget per 10 mm2. For these nuggets, Fe concentrations average 1.0 wt.%, Ir=6.0 wt.%, and Pt=44.9 wt.% (Supporting Information, Tables S6, S7). The presence of PGEs was confirmed by two SEM–EDS instruments that verified the accurate identification of PGEs through analyses of several blanks that showed no PGE content. Some concentrations are low (<1 wt.%) with high uncertainties (±100 wt.%), and elemental concentrations greater than 10 wt.% have certainties of approximately ±10 wt.%, making these results preliminary and indicating the need for further analyses. However, even though uncertainties are high, the relative elemental relationships of Fe>Pt or Pt>Fe were found to be consistent between the two instruments.

To determine the source of Tell el-Hammam nuggets and splatter, we constructed ternary diagrams. Terrestrial PGE nuggets are commonly found in ore bodies that when eroded, can become concentrated in riverine placer deposits, including those of the Jordan River floodplain. To compare Fe–Ir–Pt relationships among the Tell el-Hammam nuggets, we compiled data from nearby placer deposits in Greece¹⁰⁹, Turkey¹¹⁰¹¹¹, and Iraq¹¹², along with distant placers in Russia¹¹³¹¹⁴¹¹⁵, Canada¹¹⁶, and Alaska, USA¹¹⁷¹¹⁸. The compilation of 109 Pt-dominant placer nuggets indicates that the average Fe concentration is 8.2 wt.%, Ir=2.9 wt.%, and Pt=80.3 wt.%. For the Ir-dominant placer nuggets (n=104), Fe=0.4 wt.%, Ir=47.8 wt.%, and Pt=5.3 wt.% (Supporting Information, Tables S6, S7). The ternary diagrams reveal that the values for Pt-dominant Tell el-Hammam nuggets overlap with Pt-dominant terrestrial placer nuggets but the Fe-dominant splatter is dissimilar (Fig. 36a).

Fe-dominant splatter. We made 8 measurements on Tell el-Hammam Fe-dominant PGE splatter (Fig. 34d–f). The metal-rich areas average ~318 µm in length (range 20–825 µm) with an estimated concentration of 1 PGE-rich bleb per mm2, 100× more common than the Tell el-Hammam nuggets. Average concentrations are Fe=17.5 wt.%, Ir=4.7 wt.%, and Pt=1.5 wt.%.

We explored a potential extraterrestrial origin by constructing ternary diagrams for comparison of Tell el-Hammam Fe-dominant splatter with known meteorites and comets (Fig. 36b, c). We compiled data for 164 nuggets extracted from carbonaceous chondritic meteorites (e.g., Allende, Murchison, Leoville, and Adelaide) ¹¹⁹¹²⁰¹²¹¹²², seafloor cosmic spherules¹²³¹²⁴, iron meteorites ¹²²¹²⁵, Comet Wild 2¹²⁶, and cometary dust particles¹²⁶. For average weight percentages, see Supporting Information, Tables S6, S7. The Fe-dominant Tell el-Hammam splatter (Fig. 36b) closely matches nuggets from carbonaceous chondrites and cosmic spherules but is a weak match for most iron meteorites (Fig. 36c). In addition, the Tell el-Hammam nuggets are similar to four cometary particles, two of which were collected during the Stardust flyby mission of Comet Wild 2 in 2004¹²⁶. For average weight percentages, see Supporting Information, Tables S6, S7.

To further explore an extraterrestrial connection for Tell el-Hammam Fe-dominant splatter, we compiled wt.% data for Tell el-Hammam PGEs (Rh, Ru, Pd, Os, Ir, and Pt) and normalized them to CI chondrites using values from Anders and Grevasse¹²⁷. We compared those values to CI-normalized nuggets in carbonaceous chondrites, including CV-type chondrites (e.g., Allende) and CM types (e.g., Murchison) ¹¹⁹¹²⁰¹²²¹²⁸¹²⁹¹³⁰¹³¹, seafloor cosmic spherules¹²⁴, micrometeorites¹²³, and iron meteorites¹²²¹²⁵. These results are shown in Fig. 36d.

The Tell el-Hammam Fe-dominant splatter closely matches all types of extraterrestrial material with a similar pattern among all data sets: Pd has the lowest normalized values and Os and/or Ir have the highest, closely followed by Pt. The Tell el-Hammam splatter was also compared to the CI-normalized wt.% of bulk meteoritic material from CV- and CM-type chondrites (Fig. 36d). The composition of Tell el-Hammam splatter shows poor correlation with bulk chondritic materials, although the splatter is an excellent geochemical match with the PGE nuggets inside them. In summary, the CI normalization of PGEs suggests an extraterrestrial origin for the Fe-dominant Tell el-Hammam splatter, just as the ternary diagrams also suggest an extraterrestrial source. The correspondence of these two independent results suggests that the quantification of PGEs is sufficiently accurate in this study.

Another unusually abundant element, Mo, is also associated with Fe-dominant splatter but not with Pt-dominant nuggets. Mo averages 0.3 wt.% with up to 1.1 wt.% detected in Fe-dominant splatter but with none detected in Tell el-Hammam Pt-dominant nuggets. Mo also is not reported in any terrestrial placer nuggets and occurs in low concentrations (less than ~0.02 wt.%) in iron meteorites. In contrast, Mo is reported at high concentrations in PGE nuggets from carbonaceous chondrites (~11.5 wt.%), cosmic spherules (0.6 wt.%), and cometary material (5.8 wt.%). Thus, the Mo content of Tell el-Hammam splatter appears dissimilar to terrestrial material but overlaps values of known cosmic material, suggesting an extraterrestrial origin.

Based on the volume and weight of the meltglass, we estimate that the extraterrestrial- like metallic Tell el-Hammam Fe-dominant splatter represents <1 wt.% of the total mass of meltglass. This low concentration is typical of low impactor content in impact ejecta (<1 wt.%)¹⁰².

Footnotes

102. Wakita, S., Johnson, B. C., Denton, C. A. & Davison, T. M. (2021) Jetting during oblique impacts of spherical impactors. Icarus 360, 114365.

109. Economou-Eliopoulos, M., Eliopoulos, D. G. & Tsoupas, G. (2017) On the diversity of the PGE content in chromitites hosted in ophiolites and in porphyry-Cu systems: Controlling factors. Ore Geology Reviews 88, 156–173.

110. Cabri, L. J., Harris, D. C. & Weiser, T. W. (1996) Mineralogy and distribution of platinum-group mineral (PGM) placer deposits of the world. Exploration and Mining Geology 2, 73–167.

111. Uysal, I. (2008) Platinum-group minerals (PGM) and other solid inclusions in the Elbistan-Kahramanmaraş mantle-hosted ophiolitic chromitites, south-eastern Turkey: their petrogenetic significance. Turkish Journal of Earth Sciences 17, 729–740.

112. Jansen, M. et al. (2016) Platinum group placer minerals in ancient gold artifacts— Geochemistry and osmium isotopes of inclusions in Early Bronze Age gold from Ur/Mesopotamia. Journal of Archaeological Science 68, 12–23.

113. Tolstykh, N. D., Sidorov, E. G., Laajoki, K. V., Krivenko, A. P. & Podlipskiy, M. (2000) The association of platinum-group minerals in placers of the Pustaya River, Kamchatka, Russia. Canadian Mineralogist 38, 1251–1264.

114. Okrugin, A. (2001) Mineral parageneses and the origin of isoferroplatinum nuggets from the Ignali placer deposit (Siberian platform).

115. Zaccarini, F. et al. (2013) Platinum-group minerals (PGM) nuggets from alluvial–eluvial placer deposits in the concentrically zoned mafic-ultramafic Uktus complex (Central Urals, Russia). European Journal of Mineralogy 25, 519–531.

116. Barkov, A., Martin, R., Fleet, M., Nixon, G. & Levson, V. (2008) New data on associations of platinum-group minerals in placer deposits of British Columbia, Canada. Mineralogy and Petrology 92, 9–29.

117. Tolstykh, N. D., Foley, J. Y., Sidorov, E. G. & Laajoki, K. V. (2002) Composition of the platinum-group minerals in the Salmon River placer deposit, Goodnews Bay, Alaska. Canadian Mineralogist 40, 463–471.

118. Fedortchouk, Y. et al. (2009) Major- and trace-element composition of platinum group minerals and their inclusions from several Yukon placers. Yukon Exploration and Geology, 185–196.

119. Harries, D., Berg, T., Langenhorst, F. & Palme, H. (2012) Structural clues to the origin of refractory metal alloys as condensates of the solar nebula. Meteoritics & Planetary Science 47, 2148–2159.

120. Daly, L. et al. (2017) In situ analysis of refractory metal nuggets in carbonaceous chondrites. Geochimica et Cosmochimica Acta 216, 61–81.

121. Schwander, D. (2014) Extraktion und nanoanalytische Charakterisierung refraktärer Nanometallpartikel frühester solarer Materie und Synthese metallischer Nanopartikel aus dotierten Ca–Mg–Al–Si-Schmelzen. Universitätsbibliothek Mainz.

122. Bonté, P., Jehanno, C., Maurette, M. & Brownlee, D. (1987) Platinum metals and microstructure in magnetic deep-sea cosmic spherules. Journal of Geophysical Research 92, E641–E648.

123. Rudraswami, N., Parashar, K. & Shyam Prasad, M. (2011) Micrometer- and nanometer-sized platinum group nuggets in micrometeorites from deep-sea sediments of the Indian Ocean. Meteoritics & Planetary Science 46, 470–491.

124. Rudraswami, N. et al. (2014) Refractory metal nuggets in different types of cosmic spherules. Geochimica et Cosmochimica Acta 131, 247–266.

125. Brownlee, D., Bates, B. & Wheelock, M. (1984) Extraterrestrial platinum group nuggets in deep-sea sediments. Nature 309, 693–695.

126. Joswiak, D., Brownlee, D., Nguyen, A. & Messenger, S. (2017) Refractory materials in comet samples. Meteoritics & Planetary Science 52, 1612–1648.

127. Anders, E. & Grevesse, N. (1989) Abundances of the elements: Meteoritic and solar. Geochimica et Cosmochimica Acta 53, 197–214.

128. Berg, T. et al. (2009) Direct evidence for condensation in the early solar system and implications for nebular cooling rates. Astrophysical Journal Letters 702, L172.

129. Palme, H., Hutcheon, I. & Spettel, B. (1994) Composition and origin of refractory- metal-rich assemblages in a Ca, Al-rich Allende inclusion. Geochimica et Cosmochimica Acta 58, 495–513.

130. Schwander, D., Berg, T., Harries, D., Schönhense, G. & Ott, U. (2014) Composition and clues to the origin of refractory metal nuggets extracted from chondritic meteorites. Meteoritics & Planetary Science 49, 1888–1901.

131. Wark, D. & Lovering, J. Refractory/ platinum metal grains in Allende calcium– aluminium-rich clasts (CARCs): possible exotic presolar material? In Lunar and Planetary Science Conference.

Platinum, iridium, and palladium in sediment

from Bunch et al. (2021:40)

For Tell el-Hammam bulk sediment, neutron activation analyses show Pt abundance peaks in the destruction layer of all profiles tested (Fig. 37a–d) at ~2× to 8× an average crustal abundance of 0.5 ppb. Sedimentary Ir was below detection at <0.1 ppb for the palace, temple, and ring road, but unusually high in the wadi, where values peaked at 1.0 ppb, ~50× larger than a crustal abundance of 0.02 ppb (Supporting Information, Table S3). Also, Pt/Pd ratios in bulk sediment from the destruction layers are anomalously higher than background layers by ~4× to 14× (Fig. 37e–h). Discussion of Pt, Ir, and Pd. Abundances of Pt, Ir, and the Pt/Pd ratios all peak in sediment at or near the top of the destruction layer, suggesting an influx of those elements at 1650 BCE, most likely from both extraterrestrial and terrestrial sources. Sedimentary concentrations of Ir only peak in the wadi samples and were not detectable at the other three sites for unknown reasons.

Meltglass vesicles lined with metal‑rich minerals

from Bunch et al. (2021:40,43)

The interior portions of many melted pieces of mudbrick, roofing clay, and pottery are highly vesicular, and the walls of these vesicles nearly always display an array of metal-rich crystals (Fig. 38). These include elemental iron and iron oxides, labeled as FeO, but is actually oxidized as hematite (Fe2O3) with a melting point of ~1565 °C; magnetite (Fe3O4) that melts at ~1590 °C; and/or elemental iron (Fe) melting at ~1538 °C (Fig. 38a, b, d, f, g). Also observed on vesicle walls were crystals of Fe phosphide (Fe2P) that melts at ~1100 °C (Fig. 38c, g), manganese oxide (MnO) at ~1945 °C (Fig. 38d), calcium phosphate (Ca3(PO4)2) at ~1670 °C (Fig. 38e), and calcium silicate (CaSiO2) at ~2130 °C (Fig. 38e). Discussion of minerals in vesicles. In some cases, these mineral crystals appear to have crystallized from the molten matrix as it solidified. In other cases, it appears that they plated onto the vesicle surface, suggesting that they may have condensed through vapor deposition from the high-temperature, mineral-saturated atmosphere within the vesicle.

Melted iron and titanium

from Bunch et al. (2021:43)

SEM inspection of the palace mudbrick meltglass revealed partially melted grains of magnetite (Fe3O4) with a melting point of ~1590 °C (Fig. 39a, b) and titanomagnetite (TiFe2O4) with a melting point of ~1550 °C (Fig. 39c, d). The latter is an oxyspinel that commonly occurs as discrete grains or as an exsolution product within magnetite. The chemical composition of magnetite at equilibrium is 72.36 wt.% Fe and 27.64 wt.% O. Titanomagnetite is 21.42 wt.% Ti, 49.96 wt.% Fe, and 28.63 wt.% O. SEM–EDS analysis confirms similar compositions for the observed Tall el-Hammam grains. Discussion of melted Fe and Ti. These grains display bubble-rich features that are commonly associated with grain fractures. There are several possibilities.

Approximately 20% of the time, magnetite grains are reported to be naturally overprinted by porous magnetite as a precipitation product, creating a bubble-like texture¹³⁴

Alternatively, these features may be textures caused by differential dissolution^135,136

The grains may have been exposed to temperatures equal to or greater than their melting point, causing the outgassing of volatiles or the rapid reduction of iron oxides

Because of the morphological dissimilarity of Tall el-Hammam grains to published examples of grains altered by precipitation and dissolution, we infer that these grains were altered by exposure to high temperatures.

Footnotes

134. Makvandi, S., Beaudoin, G., McClenaghan, B. M. & Layton-Matthews, D. (2015) The surface texture and morphology of magnetite from the Izok Lake volcanogenic massive sulfide deposit and local glacial sediments, Nunavut, Canada: Application to mineral exploration. Journal of Geochemical Exploration 150, 84–103.

135. Knipping, J. L. et al. (2015) Trace elements in magnetite from massive iron oxide-apatite deposits indicate a combined formation by igneous and magmatic-hydrothermal processes. Geochimica et Cosmochimica Acta 171, 15–38.

136. Knipping, J. L. et al. (2019) In-situ iron isotope analyses reveal igneous and magmatic-hydrothermal growth of magnetite at the Los Colorados Kiruna-type iron oxide- apatite deposit, Chile. American Mineralogist 104, 471–484.

Melted iron sulfide and iron phosphide

from Bunch et al. (2021:43-)

Sulfide and phosphide grains were found attached to the walls of the vesicles within mudbrick meltglass. SEM–EDS analyses of palace mudbrick meltglass identified melted Fe sulfide (FeS), also known as troilite (Figs. 40, 41), with a composition of 63.53 wt.% Fe and 36.47 wt.% S and a melting point of ~1194 °C. Commonly found associated with the Fe sulfide, Fe phosphide (Fe2P; Fig. 40b, e) is a nickel-poor variety of barringerite, a mineral first identified at Meteor Crater in Arizona. Another variant of Fe phosphide, Fe3P, was also identified in melted mudbrick from the palace. Both phosphide variants melt at ~1100 °C. Fe phosphide is common in meteorites, but although terrestrially rare, Fe2P is found in pyrometamorphic rocks, such as are found in the Hatrurim Formation in nearby Israel¹³⁷. Britvin et al.¹³⁷ report that the local Fe phosphide displays averages for Fe at 76.4 wt.% and P at 21.4 wt.%, with small amounts of Ni, Co, and Cr at 2.2 wt.%. The composition of Fe phosphide found at Tell el-Hammam is comparable, averaging 78.3 wt.% Fe and 21.7 wt.% P. However, unlike those Fe2P grains from Israel, the Tell el-Hammam grains lack detectable Ni, Co, and Cr.

Discussion of iron sulfide and phosphide. Visual inspection indicated that the sulfide and phosphide grains were attached to the inner surfaces of vesicles, and therefore, most likely formed by vapor deposition at >1100 °C, rather than by crystallization from the melted matrix. Troilite (FeS) is very rare terrestrially but common in meteoritic material^81,138. Harris et al.¹³⁸ reported finding inclusions of troilite (FeS) as meteoritic clasts in Chilean meltglass proposed to have derived from a cosmic airburst that left meltglass on the surface along a 19-km-long stretch of the Atacama Desert approximately 12,800 years ago. At that site, troilite is typically found lining the walls of vesicles in the meltglass, as is the case for Tell el-Hammam meltglass.

Footnotes

81. Bunch, T. E. et al. (2012) Very high- temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

137. Britvin, S., Murashko, M., Vapnik, E., Polekhovsky, Y. S. & Krivovichev, S. (2017) Barringerite Fe2P from pyrometamorphic rocks of the Hatrurim Formation, Israel. Geology of Ore Deposits 59, 619–625.

138. Harris, R. & Schultz, P. Evidence of multiple cometary airbursts during the Pleistocene from Pica (Chile), Dakhleh (Egypt), and Edeowie (Australia) glasses. In Lunar and Planetary Science Conference, abstract 2229.

Melted calcium phosphide

from Bunch et al. (2021:44)

SEM–EDS analyses also show that vesicles in melted mudbrick from the palace contain calcium phosphide (Ca3P2) (Fig. 42). This mineral has a stoichiometric composition of ~66.0 wt.% Ca and ~34.0 wt.% P and melts at ~1600 °C (Table 1). Unlike Fe sulfide and Fe phosphide discussed above that appear to have formed by vapor deposition, these examples most likely crystallized from the molten Ca–Al–Si matrix material.

Melted calcium silicate (wollastonite)

from Bunch et al. (2021:44)

SEM–EDS analyses of palace mudbrick meltglass (Fig. 43a, b) and melted pottery (Fig. 43c) reveal the presence of Ca silicate, also known as wollastonite (CaSiO3), with a composition of 48.3 wt.% CaO and 51.7 wt.% SiO2 and a melting point ~1540 °C (Table 1). These crystals are mostly found on broken surfaces of the matrix but also are sometimes observed inside vesicles. Unlike Fe sulfide and Fe phosphide above, which appear to have formed by vapor deposition, these crystals appear to have condensed from the molten matrix as it cooled.

Human bones in the destruction layer

Upper tall

from Bunch et al. (2021:44-45)

If the MB II destruction event at Tell el-Hammam was of sufficient magnitude and abruptness to be fatal for human inhabitants, as the evidence indicates, human remains should exist in the MB II layer. Indeed, human skeletal remains of sufficient size to be positively identified were found on the upper ring road that encircled the upper tall between the MB II defensive fortification wall and the outer wall of the MB II palace. Two human skulls were found about 20 cm apart (Fig. 44a, b), adjacent to a portion of a pelvis and a likely arm bone fragment. One skull was missing the mandible, and the right orbit was crushed about 50%. The second skull fragment consisted only of the upper dentition and lower half of the right orbit. Only two or three rib fragments were found and no other long bones were recovered. The forensic evidence suggests that the two bodies may have been decapitated, dismembered, and disarticulated. The record indicates that most of the bones had been shattered into small pieces and mixed into a matrix of pulverized mudbricks. Currently, it is not possible to determine if the small bones are from humans or small mammals, but their proximity to identifiable human bones makes it most likely that they are human. If so, only ~10% of the combined original bone mass of both humans is present as observable fragments within a 75-cm radius from the skulls. The remaining 90% of the two skeletons are missing and assumed to have been destroyed and/or located further away in the sediment matrix. These skeletons were found on the roadway around the upper tall, where the road was 3–4 m wide. The top of the nearby rampart was several meters wide. The remains were found at a depth of about four meters below the modern surface, well-sealed and undisturbed beneath archaeological sterile strata. The bodies had been rapidly entombed by pulverized mudbrick containing abundant ash and charcoal. No weapons were found associated with the skeletons or evidence of damage by weapons, and neither body showed any indication of exposure to scavengers. Although humans can be mortally affected by earthquakes, volcanism, and warfare, these bone characteristics, both individually and collectively, show no evidence that these human deaths were caused by such events. Furthermore, even though these bones were found in close association with large charcoal fragments, the bones lack evidence of direct exposure to fire, except for the extreme upper ends. Radiocarbon ages of the surrounding charcoal (~1650 BCE) are contemporary with those elsewhere in the destruction event.

We also searched and found human bone fragments in palace bulk sediments, ~15 m away from the skeletons on the ring road. We quantified bone abundance in the fraction using a >1.2 mm screen (#12 ASTM sieve). The destruction layer was found to contain ~19 bone fragments per kilogram, weighing 3.2 g/kg. The largest bone was ~2.1 cm long ×0.8 cm wide (average size of bones=0.6×0.2 cm). In nine other samples, three above the destruction layer and six below, no other bone fragments were observed. After excavating nearly 100 squares (0.36 ha or ~1% of the site), researchers have found ~10 partial human skeletons, out of an estimated city population of ~8000 people². However, dozens to hundreds of broken and disarticulated bone fragments have been found in each of the 100 squares but these were too small to be conclusively identified as human or animal.

Footnotes

2. Silvia, P. J. (2015) The Middle Bronze Age civilization-ending destruction of the Middle Ghor. Ph.D. thesis, Trinity Southwest University

Lower tall

from Bunch et al. (2021:45-46)

During Season 6¹³⁹, excavations were conducted in two 6-by-6-m squares along the ring road of the lower tall. Both squares revealed a significant abundance of disarticulated and fragmented human skeletal remains in the MB II destruction layer¹³⁹ (Fig. 44c). In one square, three partially intact skeletons were found. All bones observed were embedded in a loose debris matrix composed of pulverized mudbrick, ash, and charcoal (Fig. 44c). There are no indications of intentional burial, scavenging, accidental death, violence, or battle damage.

Two osteologists examined the bones of two adults and one child¹³⁹. Disarticulation of the skeletons was generally severe, and for the adult skeletons, only leg bones were preserved. For one skeleton, ~10 cm of the ends of both femurs showed evidence of charring. The remaining skeleton was represented by many fragmented bones found in the surrounding matrix. Metatarsal bones were abnormally hyper-extended (i.e., joints were over-stretched) and the proximal phalanges were hyper-flexed at almost 90 degrees to the metatarsals. The right knee joint of one skeleton also was hyper-extended¹³⁹. In a nearby child’s skeleton, the legs were hyper-flexed backward and the knee joints were disarticulated. Another skeleton was found buried in a crouching position with the hands raised to the face, a posture commonly adopted for protecting the head, as occurred during the volcanic eruption at Pompeii¹⁴⁰.

Bones were also found in another square, ~6 m south of the square containing the skeletons. This square contained ~100 bones/kg with average length of 5.0 mm (range 0.5 mm–4.7 cm) and average width of 1.0 mm (range 0.5–5.0 mm). The largest was a small rib bone (4 by 47 mm), either from a human infant or a small mammal. The bone fragments weighed ~6.0 g/kg.

We also observed a 3.5-mm-long charred bone that had been splashed with meltglass (Fig. 45). In one case molten sediment had partially melted and mixed with the bone, flowed, and cooled in place. Previous experiments by Moore et al.¹⁷ suggest that such melting occurs at ≥1500 °C.

These bones also were associated with geochemical anomalies. The rib bone is visibly salt-encrusted, measured by SEM–EDS at ~46 wt.% NaCl, and the NaCl content of the attached sediment was very high at ~54 wt.% (Fig. 46a). Anomalously high concentrations of salt were found only associated with the bones and sediment in the destruction layer at 1650 BCE, and not in strata above or below, indicating an unusual influx of salt at that time. The rib bone also exhibits several nuggets of silver and tin oxide (SnO2) (Fig. 46b) with morphologies suggesting that they splashed onto the bone and sediment while molten. Ag melts at ≥961 °C and SnO2 at ≥1630 °C, although elemental Sn melts at ~232 °C. The tin and silver nuggets are also similar to those observed in the surface of melted mudbricks in the palace that were found fused to meltglass in the temple complex (Fig. 46c) and observed splashed across loose sediment (Fig. 46d).

Footnotes

139. Collins, S. & Aljarrah, H. (2011) Tall el-Hammam Season Six, 2011: Excavation, Survey, Interpretations and Insights. Department of Antiquities of Jordan, Amman

140. Knüsel, C. J. (2014) Crouching in fear: Terms of engagement for funerary remains. Journal of Social Archaeology 14, 26–58

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

Discussion of human bones

from Bunch et al. (2021:46-47)

A medical doctor (co-author T.W.) inspected the human bones and concluded that the injuries occurred perimortem, including damage to the eye socket of one skull. We propose that the individuals represented by the bones were violently torn apart by a powerful airburst/impact, leaving only a few hand and foot bones still articulated and unbroken. It would not be possible to duplicate these injuries and disperse the bones as found in this layer by warfare or by accidental falls from a great height, e.g., off the adjacent rampart. Although tornadoes (max winds of ~512 km/h or ~318 mph) can cause bone breakage, organ damage, and disarticulation (Supporting Information, Text S3), they are exceedingly rare in Jordan or Israel and typically of low intensity. In any event, no known tornado has been shown to burn bones and break them into small fragments.

The most severe known injuries to human bodies result from the impact of airborne high-velocity objects, such as during explosions and tornadoes (Supporting Information, Text S3). In addition, the ground-hugging blast wave from an airburst/impact would be laden with high-velocity missiles, including sand, gravel, pulverized mudbrick, plaster fragments, potsherds, broken branches, and shattered timbers. At tornado-force wind velocities and extremely high ambient temperatures, these missiles would be capable of incinerating or stripping flesh and crushing bones. Current evidence suggests that the human mortality rate at Tell el-Hammam was very high, so that most likely none of the ~8000 inhabitants survived.

Based on the distribution of human bones on the upper and lower tall, we propose that the force of a high-temperature, debris-laden, high-velocity blast wave from an airburst/impact

incinerated and flayed their exposed flesh
decapitated and dismembered some individuals
shattered many bones into mostly cm-sized fragments
scattered their bones across several meters
buried the bones in the destruction layer, and
charred or disintegrated any bones that were still exposed.

In summary, although man-made explosives and atomic bombs can account for an extreme range of damage to humans, they can be ruled out because of the age of the site. In addition, warfare, accidents, and tornadoes can be eliminated because they are incapable of causing the observed severe skeletal damage at Tell el-Hammam. The circumstances and condition of the human bones and fragments suggest that at the moment of death, these individuals were going about normal activities inside the palace, on the upper ring road, and/or on the rampart above the road, where they were struck by a high-temperature thermal pulse, followed by a hyper-velocity blast wave from a catastrophic cosmic airburst. This event was most likely larger than the airburst at Tunguska, Siberia in 1908, where ~500 reindeer and several herders within the blast radius suffered severe burns and were killed, but suffered no disarticulation¹⁴².

Footnotes

142. Jenniskens, P., Popova, O. P., Glazachev, D. O., Podobnaya, E. D. & Kartashova, A. P. (2019) Tunguska eyewitness accounts, injuries, and casualties. Icarus 327, 4–18

Implications of high salinity for agriculture

Introduction

from Bunch et al. (2021:47-)

Early general observations at Tall el-Hammam indicated that the destruction layer is marked by anomalously high concentrations of salt. For example, where the carbon-rich, potentially fertile destruction layer is exposed on the surface of the lower tall, it is unsuitable for agriculture until the salts are leached using local spring water. Some areas of the lower tall have never been farmed, and the MB II surface exposed at ground level turns white with salt crystals following rainfall. For most excavated squares, the newly exposed MB II surface from each day’s archeological excavation produced an obvious white salt crust overnight as humidity leached salt to the surface. Also, we observed that the newly exposed mud/ash mortar between mudbricks hardened after exposure because of salt crystals and that many pottery sherds and some bones from the destruction layer were encrusted with large salt crystals.

We also discovered melted salt crystals in the destruction layer. For example, some palace meltglass displayed blebs of non-crystalline, melted potassium chloride, KCl (Fig. 47), which has a melting point of ~772 °C and a boiling point of 1420 °C. KCl is stoichiometrically composed of ~52.4 wt.% K and 47.6 wt.% Cl. We also identified melted sodium chloride, NaCl (Fig. 47c, d), which has a melting point of 801 °C and a boiling point of 1465 °C. NaCl is composed of ~39.3 wt.% Na and ~60.7 wt.% Cl. Even though both of these salts melt at low temperatures and alone are not definitive indicators of a cosmic impact, they appear non-crystalline and are fused into the meltglass, making them indicative of exposure to temperatures sufficient to melt sediment (>1200 °C). Also, the blebs display vesicles from outgassing, suggesting that they may have exceeded their melting points.

Using SEM–EDS analysis, six samples of melted mudbrick from the palace were found to average ~4.4 wt.% NaCl (range 2.0–9.1 wt.%), and one sample of pottery from the palace contains ~17.5 wt.% NaCl at its surface. For two samples from the temple, SEM–EDS analyses showed that some melted mudbrick contains an average of ~2.0 wt.% NaCl with associated sediment containing ~54 wt.% NaCl. Activation Laboratories in Canada used neutron activation analyses to determine salt content in samples from within, above, and below the MB II destruction layer from the palace and temple. The results showed a peak concentration of ~5.5 wt.% salt plus sulfate in the MB II layer, tapering off to about half or less above and below this layer. We also directly measured the salinity of these same samples, with the destruction layer containing ~4 wt.% salt in the palace and ~3.9 wt.% in the temple (Fig. 48). In both palace and temple areas, the salt content of two sediment samples above and two below the destruction layer exhibited values below detection at <1 wt.%. The ring road displayed values of ~3 wt.% in the destruction layer (Fig. 48) but also had high values above and below, possibly due to the erosion of salt-rich sediment onto the road

Discussion of causes for high salinity

from Bunch et al. (2021:48-49)

Numerous lines of evidence reveal the sudden, catastrophic destruction of Tall el-Hammam at ~1650 BCE². At the same time, archaeologists excavating nearby sites noted what they termed the “Late Bronze Age Gap”^2,14,143, during which ~16 cities/towns, including Tall el-Hammam, and >100 smaller villages^144–146 were abandoned across the 30-km-wide lower Jordan Valley. This abandonment continued for the entire Late Bronze Age and most of the early Iron Age. Population levels are estimated to have plummeted from ~45,000–60,000 people to only a few hundred nomadic tribespeople inhabiting the area following this destruction event². For Tall el-Hammam, the occupation gap is >600 years². In the Jericho area in the southwestern Jordan Valley, the archaeological record indicates a gap of approximately 300 years. For Tall Nimrin about 5 km north of Tall el-Hammam, there is a post-MBA occupation gap of ~500 years^14,28,147, and in addition, excavators found remains of destroyed MB II walls. No walls were taller than ~2 m, or 10 courses of mudbricks^14,28,147, and all were on the north side of Tall Nimrin, similar to 10-course-high Tall el-Hammam wall remnants that appear shielded from the proposed impact. This multi-century abandonment is particularly puzzling, given that this area contains the most fertile agricultural land within a radius of hundreds of kilometers across Jordan, Israel, and Palestine. The destruction was so remarkable and so pervasive that the ensuing name of the area became Abel, the ‘mourning grounds’ (specifically, to mourn because of a calamity)¹⁴⁸. This does not appear to have been some typical disaster that occasionally occurred due to warfare and earthquakes. Instead, it appears to be a regional civilization-ending catastrophe that depopulated more than 500 km² of the southern Jordan Valley for between 3 and 7 centuries².

So, what could have caused the long-term abandonment of the entire lower Jordan Valley with its fertile agricultural land? One potential clue is that the destruction layers in both the palace on the upper tall and the temple on the lower tall contain salts at average concentrations of ~4%, ranging up to 54 wt.%, while conversely, salt concentrations above and below the destruction layers are undetectable at <1 wt.%. In modern times, the surface sediments around Tall el-Hammam are non-saline at <0.2% salt¹⁴⁹ (Fig. 49). Elsewhere in the Kikkar, or southern Jordan Valley, ~26% of the area has salinity levels ≥1.3 wt.% with some parts >5 wt.% ^149–151 (Fig. 49).

According to the US Department of Agriculture (USDA), wheat will not germinate if the soil salt content is >1.3 wt.%, and barley will not germinate at >1.8 wt.%^152,153. Since these are the two primary cereal grains of the Ancient Near East, if the unusually high concentrations of salt recorded at Tall el-Hammam were similar throughout much of the southern Jordan Valley, no crops could have been grown until, with time, the salt leached out of the soil. Accomplishing the desalination of the soils would have taken hundreds of years, based on typical farming practices.

Although the precise origin of the peaks in salinity at Tall el-Hammam is unknown, we speculate that an impact into or an airburst above high-salinity surface sediments (26% of land in the southern Jordan Valley at >1.3% salinity) and/or above the Dead Sea (with ~34 wt.% salt content) may have distributed hypersaline water across the lower Jordan Valley. If so, this influx of salt may have substantially increased the salinity of surface sediments within the city and in the surrounding fields. Any survivors of the blast would have been unable to grow crops and therefore likely to have been forced to abandon the area. After ~600 years, the high salt concentrations were sufficiently leached out of the salt-contaminated soil to allow the return of agriculture.

Footnotes

2. Silvia, P. J. (2015) The Middle Bronze Age civilization-ending destruction of the Middle Ghor. Ph.D. thesis, Trinity Southwest University

14. Flanagan, J. W. & McCreery, D. W. (1990) First Preliminary Report of the 1989 Tell Nimrin Project. ADAJ 34, 131–152

143. Collins, S., Byers, G. A., Kobs, C. M. & Silvia, P. J. (2014) Tall el-Hammam Season Nine, 2014: Excavation, Survey, Interpretations and Insights. Department of Antiquities of Jordan, Amman

144. Ibrahim, M., Sauer, J. A. & Yassine, K. (1988) The east Jordan valley survey 1976 (Part two). Archaeology of Jordan: essays and reports, University of Jordan, Amman, 189–207

145. Ibrahim, M. A., Sauer, J. A. & Yassine, K. (1976) The East Jordan Valley Survey, 1975. Bulletin of the American Schools of Oriental Research 222, 41–66

146. Yassine, K. (2011) Tell Nimrin: An Archaeological Exploration. University of Jordan

28. Flanagan, J. W., McCreery, D. W., Yāsīn, H. A. N. & Kehrberg, I. (1996) Tall Nimrin: Preliminary report on the 1995 excavation and geological survey. ADAJ 40, 271–292

147. Flanagan, J. W., McCreery, D. W. & Yāsīn, H. A. N. (1992) Preliminary report of the 1990 excavation at Tell Nimrin. Annual of the Department of Antiquities of Jordan 36, 89–111

148. Collins, S. (2012) Tall el-Hammam is Sodom: Billington’s Heshbon identification suffers from numerous fatal flaws. Biblical Research Bulletin XII

149. Al-Rifaee, M. K. (2013) Jordan Valley. In Salinity management workshop for the CGIAR Research Program on Water, Land, and Ecosystem (WLE), Jordan

150. Ammari, T. et al. (2013) Soil salinity changes in the Jordan Valley potentially threaten sustainable irrigated agriculture. Pedosphere 23, 376–384

151. Singer, A. (2007) Saline and alkaline soils in Israel. Soils of Israel, 231–248

152. Ayers, R. S. & Westcot, D. W. (1985) Water quality for agriculture. FAO Irrigation and Drainage Paper 29, Rome

153. USDA (2011) Crop tolerance and yield potential of selected crops as influenced by irrigation water salinity (ECw) or soil salinity (ECe). USDA, Washington, DC

Coeval destruction and burning of Jericho

Introduction

from Bunch et al. (2021:49-50)

By ~1650 BCE, Tell es-Sultan, proposed as the biblical Jericho, reached its maximum extent¹⁵⁴ at ~7 ha¹⁵, about one-fifth the size of Tall el-Hammam, located ~22 km to the east. Jericho was the most prosperous city in the area and the third largest after Tall el-Hammam and Tall Nimrin. For that time, it had state-of-the-art defenses with thick walls and a massive stone revetment¹⁵⁵.

Then suddenly, the city suffered violent destruction and a fierce conflagration at the end of MB II at the same time as Tall el-Hammam²⁶. Kenyon, an early site excavator, wrote “The destruction was complete. Walls and floors were blackened or reddened by fire, and every room was filled with fallen bricks, timbers, and household utensils; in most of the rooms the fallen debris was heavily burnt²⁷”.

During the destruction event, a massive stone MBA defensive tower toppled and burned²⁶, leaving a thick layer of broken mudbricks, fire-cracked stones, broken pottery, and burned fragments of wooden beams²⁶. Along the base of a massive curving stone defensive wall adjoining the tower, a 7-to-10-m-wide destruction layer contains a thick accumulation of ash, charcoal, and carbonized wooden beams, covered by huge stones, broken mudbricks, and rubble¹⁵⁶. Marchetti et al.²⁶, another key group of site excavators, noted that the ash was white, suggesting combustion at high temperatures. However, excavators reported finding no high-temperature materials, such as melted mudbricks or pottery, suggesting temperatures of less than ~1200 °C¹⁷, the melting point of local sediment.

Near the tower was a series of storerooms gutted by fire and filled with broken storage jars and carbonized grains that were strewn across the floors^26,154,157. Almost no complete vessels were found, and instead, broken potsherds were suspended throughout the destruction matrix at different elevations²⁶. In addition, human remains were found mixed within the debris layer, and almost all the bones were burned, disarticulated, and shattered into small fragments²⁶. The excavators noted that their colors indicate exposure to high temperatures²⁶.

Kenyon reported that the massive MBA eastern wall, which faced toward Tall el-Hammam, collapsed and some of the destruction debris cascaded down the steep slope adjoining the city walls¹⁵⁸. She also concluded that the collapse of the eastward-facing fortifications had taken place before the walls were affected by fire²⁷. Overlying the crumbled defensive walls, Kenyon uncovered a thick deposit of Iron Age material, but LBA material is missing²⁴. Instead, up to one meter of culturally sterile sediment lies atop the MBA destruction layer in places, leading Kenyon to conclude that for hundreds of years after the destruction of Jericho, the city lay abandoned¹⁵⁵.

Footnotes

15. Marchetti, N., Nigro, L. & Sarie, I. (1998) Preliminary report on the first season of excavations of the Italian–Palestinian expedition at Tell es-Sultan/Jericho, April–May 1997. Palestine Exploration Quarterly 130, 121–144

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

24. Kenyon, K. M. (1952) Excavations at Jericho, 1952. Palestine Exploration Quarterly 84, 62–82

26. Marchetti, N. (2000) A century of excavations on the Spring Hill at Tell es-Sultan, ancient Jericho: A reconstruction of its stratigraphy. University of Rome; Palestinian Dept. of Antiquities

27. Kenyon, K. M. (1981) Excavations at Jericho, Vol. 3: The architecture and stratigraphy of the Tell. British School of Archaeology in Jerusalem

154. Kenyon, K. M. (1955) Excavations at Jericho, 1955. Palestine Exploration Quarterly 87, 108–117.

155. Kenyon, K. M. (1957) Digging up Jericho.

156. Nigro, L. & Taha, H. (2009) Renewed excavations and restorations at Tell es-Sultan/ancient Jericho, Fifth season—March–April 2009, 731–744.

157. Nigro, L. & Taha, H. Results of the Italian–Palestinian expedition to Tell es-Sultan: At the dawn of urbanization in Palestine. In Tell es-Sultan/Jericho in the Context of the Jordan Valley: Proceedings of the International Workshop (Ariha 2005), 1–40.

158. Kenyon, K. M. (1951) Some notes on the history of Jericho in the second millennium BC. Palestine Exploration Quarterly 83, 101–138.

Discussion of the destruction of Jericho

from Bunch et al. (2021:50)

The destruction of Jericho was not unusual. Cities in the Jordan Valley have a long history of episodic destructions by earthquakes and warfare^154,158,159. However, Kenyon found no conclusive evidence of either at ~1650 BCE¹⁵⁴, and there were no known major earthquakes in the area between ~1800 and 1560 BCE¹⁶⁰ [JW: not exactly true - see footnote ^A]. In previous destruction episodes, the inhabitants simply rebuilt immediately, but this time, Jericho was inexplicably abandoned for centuries¹⁵⁵.

The causes of the destruction of Jericho are unclear. Notably, its age is 1653 ± 18 BCE (range 1670–1626 BCE), making it statistically coeval with the destruction of Tall el-Hammam at 1661 ± 20 BCE (range 1686–1632 BCE) (Fig. 50; Supporting Information, Tables S8, S9). One possibility is that Jericho’s destruction resulted from the high-temperature thermal pulse and high-velocity blast wave of a cosmic airburst that first struck Tall el-Hammam and then Jericho, where it collapsed the fortified walls and burned the city, located ~22 km to the west of Tall el-Hammam. This is consistent with Tunguska, where Svetsov^161,162 showed that the radiation energy from the Tunguska explosion was sufficient to set fires within a diameter of ∼20 km. Thus, for Tall el-Hammam, the minimum distance of destruction is ~22 km, similar to that of the Tunguska airburst in 1908^65,161–163.

Footnotes

65. Florenskiy, K. (1965) Preliminary results from the 1961 combined Tunguska meteorite expedition. Meteoritica XXIII, 3–37.

154. Kenyon, K. M. (1955) Excavations at Jericho, 1955. Palestine Exploration Quarterly 87, 108–117.

155. Kenyon, K. M. (1957) Digging up Jericho.

158. Kenyon, K. M. (1951) Some notes on the history of Jericho in the second millennium BC. Palestine Exploration Quarterly 83, 101–138.

159. Nigro, L., Sala, M., Taha, H. & Yassine, J. (2011) The Bronze Age palace and fortifications at Tell es-Sultan/Jericho: the 6th–7th seasons (2010–2011), 571–597.

160. Migowski, C., Agnon, A., Bookman, R., Negendank, J. F. & Stein, M. (2004) Recurrence pattern of Holocene earthquakes along the Dead Sea transform revealed by varve-counting and radiocarbon dating of lacustrine sediments. Earth and Planetary Science Letters 222, 301–314.

161. Svetsov, V. (1996) Total ablation of the debris from the 1908 Tunguska explosion. Nature 383, 697–699.

162. Svetsov, V. B. (2006) Thermal radiation on the ground from large aerial bursts caused by Tunguska-like impacts. In Lunar and Planetary Science XXXVII, 1–2.

163. Kirova, O. (1965) Scattered matter from the area of fall of the Tunguska cometary meteorite. Annals of the New York Academy of Sciences 119, 235–242.

A. In her dissertation, Migowski (2001) identified a 3 cm thick Type 4 seismite with an estimated intensity of 8.7–8.8 dated to ca. 1560 BCE. See En Gedi – Master Seismic Events Table – En Gedi Core (DSEn). An analogous destruction layer at Jericho has been dated to MB III around 1650 BCE by Kenyon and others, and to about 1400 BCE by Wood and other Biblical apologists attempting to align the destruction with the Biblical Conquest narrative. There are, however, significant challenges in dating this destruction layer at Jericho; see Tell es-Sultan (Jericho).

Potential causes of the city destruction

Introduction

from Bunch et al. (2021:50)

Here, we consider 10 processes that account for some or all of the wide-ranging observations and evidence related to the destruction of Tall el-Hammam and nearby cities/villages. Table 2 lists the potential matches for 17 lines of evidence for each of these possibilities. Using this evidence, we summarize which process best explains the observed evidence at Tall el-Hammam.

Anthropogenic activities

from Bunch et al. (2021:51)

Anthropogenic activities. Matches 12 of 17 lines of evidence. These activities include glass-making; smelting gold, silver, and copper; and fashioning metals into jewelry and artifacts. During the MBA, copper smelting only reached temperatures of ~1100 °C¹⁶⁴ and glass-making reached ~1100 °C¹⁶⁴. These temperatures are too low to melt grains of chromite, quartz, or zircon at >1500 °C, and pressures are far too low to shock quartz. Downward contamination of materials from modern human activities can be eliminated because most Tall el-Hammam meltglass is buried 2 m or more beneath archaeologically sterile layers.

Footnotes

164. Beretta, M. (2017) The alchemy of glass: counterfeit, imitation, and transmutation in ancient glassmaking. Science History Publications.

Pottery-making

from Bunch et al. (2021:51)

Pottery-making. Matches only 1 of 17 lines of evidence. Maximum temperatures achievable during MBA pottery-making were <1050 °C⁷¹, making this activity incapable of melting pottery and mudbrick at >1400 °C. Also, this activity cannot melt zircon, quartz, and chromite grains at >1500 °C and cannot produce peak concentrations in Pt, Ir, Ni, Cr, or shocked quartz.

Footnotes

71. Thy, P., Segobye, A. K. & Ming, D. W. (1995) Implications of prehistoric glassy biomass slag from east-central Botswana. Journal of Archaeological Science 22, 629–637.

Normal city fires/wildfires

from Bunch et al. (2021:51)

Normal city fires/wildfires. Matches 8 of 17 lines. Besides the MB II destruction layer, several other non-MBA charcoal-rich strata were observed in the sedimentary record, indicating extensive Tall el-Hammam city fires at other times. However, none of those contain melted pottery, melted mudbricks, or any other high- temperature proxies. For comparison, after the Great Fire of London in 1666, several types of thermally- altered objects were found, including partially melted clay bricks, potsherds, and window glass¹⁶⁵, but none show a degree of melting comparable to that at Tall el-Hammam. For a modern comparison, the firebombing of Dresden, Germany, during World War II produced updrafts of ~275 km/h, and yet, maximum temperatures were no higher than ~1000 °C¹⁶⁶, which is high enough to soften but not melt glass, and too low to melt elemental iron at ~1538 °C. Typical non-impact fires cannot account for abundance peaks in Pt, Ir, Ni, and Cr, as well as the melting of zircon, quartz, and chromite, or shock metamorphism in quartz.

Footnotes

165. Museum of London (2019) What happened in the Great Fire of London?

166. Hopkins, R. P. (2008) The historiography of the Allied bombing campaign of Germany.

Midden fires

from Bunch et al. (2021:51)

Midden fires. Matches 9 of 17. Biomass glass or slag is sometimes found in midden piles of prehistoric settlements in Africa with estimated formation temperatures of 1155–1290 °C⁷¹, and this process can produce vesicular meltglass and Si-rich spherules. However, Moore et al.¹⁷ investigated examples of this biomass glass and found that temperatures did not rise high enough to melt zircon, chromite, or quartz. Furthermore, midden fires cannot produce abundance peaks in Pt, Ir, Ni, and Cr or shock metamorphism in quartz.

Footnotes

71. Thy, P., Segobye, A. K. & Ming, D. W. (1995) Implications of prehistoric glassy biomass slag from east-central Botswana. Journal of Archaeological Science 22, 629–637.

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

Warfare

from Bunch et al. (2021:51)

Warfare. Matches 7 of 17. We considered whether ancient sieges could have led to city fires in the Tall el-Hammam destruction layer. However, only one arrowhead, and no spear points or swords were found associated with any of the skeletons found in the ruins. It is common in ancient warfare that conquered cities were demolished and replaced by the invading army’s culture and religion, but there is no evidence for warfare in the destruction layer at Tall el-Hammam. In any event, ancient warfare is unable to explain melted high-temperature minerals, peaks in PGEs, and shocked quartz. For modern warfare, the detonation of military explosives can theoretically produce most of the evidence, but the Tall el-Hammam melted material comes from deeply buried strata sealed by Iron Age occupations unaffected by modern explosives. Modern defensive artillery revetments, excavated during the 1967 Middle Eastern war, were not coincident with the archaeological excavations that produced the evidence.

Earthquakes

from Bunch et al. (2021:51)

Earthquakes. Matches 5 of 17. Earthquakes can cause fires but are unable to explain most of the high-temperature melted materials, peaks in PGEs, and shocked quartz. Although earthquakes potentially can explain the directionality of the debris, all previous earthquakes left debris at Tall el-Hammam in the N/S orientation, aligned parallel to the Dead Sea rift, rather than in the observed SW/NE direction. In any event, no known major earthquakes occurred in the area in the interval from ~1800 to 1560 BCE¹⁶⁰. The only two earthquakes known to have caused major damage at Tall el-Hammam occurred in ~2100 BCE (>6.8 magnitude) and 3300 BCE (>6.0 magnitude). After both of these disasters, the inhabitants of Tall el-Hammam simply rebuilt the city².

Footnotes

160. Migowski, C., Agnon, A., Bookman, R., Negendank, J. F. & Stein, M. (2004) Recurrence pattern of Holocene earthquakes along the Dead Sea transform revealed by varve-counting and radiocarbon dating of lacustrine sediments. Earth and Planetary Science Letters 222, 301–314.

2. Silvia, P. J. (2015) The Middle Bronze Age civilization-ending destruction of the Middle Ghor. Ph.D. thesis, Trinity Southwest University

Volcanism

from Bunch et al. (2021:52)

Volcanism. Matches 12 of 17. Temperatures of most magmas are in the range of 700–1300 °C, but temperatures of komatiite magmas may occasionally reach 1600 °C¹⁶⁷. These temperatures could account for the melted zircon but are too low to melt or mechanically shock grains of quartz¹⁶⁸. Also, volcanism has never been shown to produce high-iron spherules, such as those found at Tall el-Hammam^78,81,82.

One of the largest volcanic eruptions known for the last 10,000 years occurred at ~1663–1599 BCE (3613–3549 cal BP)¹⁶⁹, centered in the eastern Mediterranean on Thera, a Greek island now known as Santorini. The explosion generated a massive tsunami that is proposed to have reached the island of Crete 110 km away and triggered the collapse of the Minoan culture, which evidence suggests was closely related to the culture at Tall el-Hammam^143,170. Approximately 60 km³ of volcanic ash and pumice were ejected during this eruption¹⁷¹, and this debris buried the MBA town of Akrotiri on the island of Thera. Related tephra deposits have also been found in Turkey and Israel, and a thin (~1 mm) layer may have reached Jordan, including Tall el-Hammam¹⁷¹. However, this massive volcanic explosion was too distant from Tall el-Hammam (>1000 km) to have caused its destruction, and also, it is dated at 40–100 years younger than the destruction and abandonment of Tall el-Hammam. We searched for but found no evidence at Tall el-Hammam of volcanic tephra, ash, pumice, or lava in any of the sedimentary profiles, indicating that no severe contemporary eruptions occurred near Tall el-Hammam at ~1650 BCE.

Footnotes

167. Connolly, B. D. (2011) HSE and Re-Os systematics of the 3.3 Ga Weltevreden komatiites from the Barberton Greenstone Belt, South Africa: Implications for early Earth’s mantle evolution.

168. de Silva, S. & Sharpton, V. (1988) Explosive volcanism, shock metamorphism and the KT boundary. In Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality, Vol. 38.

78. Pino, M. et al. (2019) Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka. Scientific Reports 9, 4413.

81. Bunch, T. E. et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

82. Wittke, J. H. et al. (2013) Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. Proceedings of the National Academy of Sciences 110, E2088–E2097.

169. Ramsey, C. B., Manning, S. W. & Galimberti, M. (2004) Dating the volcanic eruption at Thera. Radiocarbon 46, 325–344.

143. Collins, S., Byers, G. A., Kobs, C. M. & Silvia, P. J. (2014) Tall el-Hammam Season Nine, 2014: Excavation, Survey, Interpretations and Insights. Department of Antiquities of Jordan, Amman.

170. Collins, S. (2006) The search for Sodom & Gomorrah. Trinity Southwest University Press.

171. Sigurdsson, H., Carey, S. & Devine, J. (1990) Assessment of mass, dynamics and environmental effects of the Minoan eruption of Santorini volcano. In Thera and the Aegean World III, Vol. 2, 100–112.

Lightning

from Bunch et al. (2021:53)

Lightning. Matches 3 of 17. Lightning strikes can also produce shocked quartz grains, but these shock lamellae are confined to the outer 0.33 µm of quartz grains and do not propagate into the interior, unlike the shocked grains found at Tall el-Hammam⁶². Furthermore, low values for remanent magnetism indicate that lightning could not have produced the Tall el-Hammam melted material tested. Also, lightning would not account for high-velocity winds, the directionality of debris, and the rapid destruction of buildings and walls spanning a distance of ~400 m across the tall.

Footnotes

62. Gieré, R. et al. (2015) Lightning-induced shock lamellae in quartz. American Mineralogist 100, 1645–1648.

Crater-forming cosmic impact

from Bunch et al. (2021:53)

Crater-forming cosmic impact. Matches 17 of 17. Although a hard impact potentially accounts for all of the evidence, this mechanism seems somewhat unlikely because there is currently no known crater in the area. However, although improbable, a crater with a diameter of less than a few hundred meters may be buried in the Jordan River floodplain or hidden underwater at the northern end of the Dead Sea. The Jordan Valley has been subject to massive seasonal floods for more than 3000 years, sufficient time for fluvial deposition to conceal a small crater. Alternately, an aerial burst of a bolide can produce a “shotgun blast” of small objects that can reach the ground and create small craters that range in diameter from a few meters to a few tens of meters. The action of wind and water could readily and rapidly erase any surface evidence of such craters, especially in this area of rapid sediment deposition in the active floodplain of the lower Jordan Valley. Note in Table 3 that all the evidence for Tall el-Hammam matches that of crater-forming impacts such as the K–Pg, except for the lack of a crater.

Footnotes

Cosmic airburst

from Bunch et al. (2021:53)

Cosmic airburst. Also matches 17 of 17 lines of evidence. Overall, one or multiple Tunguska-sized airbursts by a comet or meteorite seems most likely to account for the wide-ranging suite of observed evidence for the destruction of Tall el-Hammam (Table 3). In the future, it would be useful to search for proxies across the Jordan Valley at various distances from Tall el-Hammam. Any discernible pattern would help locate ground zero, where proxy concentrations would be the largest. We know from archeological evidence that 16 cities/towns and >100 villages across the southern Jordan Valley were abandoned at this time, but not whether their walls were destroyed or if high-temperature, high- pressure proxies are present at those sites. Because airburst/impact proxies fall off exponentially with distance from ground zero, the distribution would help determine the intensity of the event.

It is worth speculating that a remarkable catastrophe, such as the destruction of Tall el-Hammam by a cosmic object, may have generated an oral tradition that, after being passed down through many generations, became the source of the written story of biblical Sodom in Genesis. The description in Genesis of the destruction of an urban center in the Dead Sea area is consistent with having been an eyewitness account of a cosmic airburst, e.g., (i) stones fell from the sky; (ii) fire came down from the sky; (iii) thick smoke rose from the fires; (iv) a major city was devastated; (v) city inhabitants were killed; and (vi) area crops were destroyed. If so, the destruction of Tall el-Hammam is possibly the second oldest known incident of impact-related destruction of a human settlement, after Abu Hureyra in Syria ~12,800 years ago^17,172,173.

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

172. Moore, A., Hillman, G. & Legge, A. (2000) Village on the Euphrates: From foraging to farming at Abu Hureyra. Oxford University Press.

173. Moore, A. & Kennett, D. (2013) Cosmic impact, the Younger Dryas, Abu Hureyra, and the inception of agriculture in Western Asia. Eurasian Prehistory 10, 57–66.

Note by JW - Missing from this list is a natural gas eexplosion

The Dead Sea basin has geological conditions that could allow a non-anthropogenic natural gas explosion in rare circumstances, including in the Lisan–Kikar plain near Tall el-Hammam. This hypothesis does not require human activity; it would depend on subsurface gas accumulation, sudden release, and ignition. Old non-biogenic gas has been detected on seismic sections at depths as shallow as about 500 m, and a natural gas blowout reportedly occurred in a geotechnical well drilled on the Jordanian side in the 1990s (personal communicaation, Amoco V.P., 1999).

Analogous destruction events

Comparison to Trinity atomic detonation

from Bunch et al. (2021:53-54)

Comparison to Trinity atomic detonation. In 1945, the first atomic bomb test, called Trinity, took place at the Alamogordo Bombing Range near Socorro, New Mexico. The bomb exploded in the atmosphere atop a 30-m tower, making the detonation an airburst in which the explosive yield equaled ~22 kilotons of TNT equivalent^174,175. This atomic blast was several orders of magnitude less powerful than the Tunguska cosmic airburst in 1908 in Siberia, estimated at ~3–30 megatons of TNT equivalent at an altitude of 5–10 km¹⁷⁶.

The Trinity fireball had a maximum fireball temperature of ~300,000 °C¹⁷⁵ and an average plume temperature of ~8000 °C^64,177, hotter than the surface of the sun (>5500 °C) and several times brighter⁸¹. After ~3 s, the plume temperatures fell to ~1713 °C¹⁷⁵, the melting point of quartz.

The Trinity explosion formed a shallow crater ~1.4 m deep and ~80 m in diameter and ejected molten surface sediment that fell back as green glass, commonly referred to as trinitite. This melted green glass was found on the ground surface for a diameter of ~400 m, along with a high abundance of green glass spherules both macroscopic (0.1–5 mm) and microscopic (microns to tens of microns), the latter having been found as far as 2 km from ground zero. Bunch et al.⁸¹ reported the presence of high- temperature melted minerals in trinitite, indicating ground temperatures of >2200 °C, consistent with reported conditions¹⁷⁵.

Even though an atomic bomb blast is not applicable because of the historic absence of atomic explosions in the area, an atomic blast produces a wide range of melt products that are morphologically indistinguishable from the melted material found at Tall el-Hammam (Fig. 51). These include shocked quartz⁶⁴; melted and decorated zircon grains (Fig. 51a, b); globules of melted material (Fig. 51c, d); meltglass containing large vesicles lined with Fe-rich crystals likely deposited by vapor deposition (Fig. 51e, f); and spherules embedded in a meltglass matrix (Fig. 51g, h). Also, atomic detonations can replicate the physical destruction of buildings, the human lethality, and the incineration of a city, as occurred in World War II.

Footnotes

64. Eby, G. N. et al. (2015) Trinitite redux: Mineralogy and petrology. American Mineralogist 100, 427–441.

81. Bunch, T. E. et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

174. Hanson, S. K. et al. (2016) Measurements of extinct fission products in nuclear bomb debris: Determination of the yield of the Trinity nuclear test 70 y later. Proceedings of the National Academy of Sciences 113, 8104–8108.

175. Glasstone, S. & Dolan, P. J. (1977) The Effects of Nuclear Weapons, third edition. U.S. Government Printing Office.

176. Wheeler, L. F. & Mathias, D. L. (2019) Probabilistic assessment of Tunguska-scale asteroid impacts. Icarus 327, 83–96.

177. Hermes, R. E. & Strickfaden, W. B. (2005) A new look at Trinitite. Nuclear Weapons Journal 2, 2–7.

Comparison to Tunguska cosmic airburst

from Bunch et al. (2021:54)

Comparison to Tunguska cosmic airburst. On June 30, 1908, a cosmic airburst occurred over Tunguska, Russia in a remote part of Siberia. The bolide has been variously estimated as a low-density rocky asteroid or a small comet with a diameter of 50–80 m ^65,162. The blast yield is estimated at ~3–30 megatons of TNT equivalent with a burst altitude of ~5–10 km. The airburst generated a pressure wave that toppled or snapped >80 million trees, some up to 1 m in diameter¹⁷⁸ across ~2000 km² in a radial pattern away from ground zero^65,162,179.

The fallen trees partially burned across an area of ~200 km² with a radius of ~8 km. Estimated wind velocities were ~40–70 m/s (144–250 km/h), greater than an EF-3 tornado¹⁸⁰. Tunguska’s blast pressure not only toppled trees but also pressed the tree fluids from the bark into the pre-existing tree rings of the surviving trees¹⁸¹.

The Tunguska airburst deposited high-temperature melted spherules ^65,163, meltglass ^163,182,183, diamonds ^184,185, shocked quartz ^67,186, and iridium ¹⁸⁷. All these impact-related proxies have also been observed at Tall el-Hammam.

The temperature of the Tunguska fireball is unknown but estimated as >10,000 °C¹⁸⁸. The airburst initially ignited ~200 km² of the forest before spreading to consume ~500 km² of forest¹⁶². A similar but much smaller airburst occurred over Chelyabinsk, Russia, on February 15, 2013, with a yield of ~500 kilotons of TNT equivalent with a burst altitude of 12 km.

Even though the Tunguska area was sparsely inhabited, the blast killed ~3 of the ~30 people that were within or near the zone of fallen trees. Some of the injured survivors remained unconscious for hours to days¹⁴². Nearly everyone experienced severe burns within an eight-km radius of ground zero across an area covering ~200 km². Also, as many as 500 reindeer were killed by the blast and hundreds more were severely burned¹⁴². Based on this evidence, we propose that an aerial detonation likely larger than the one at Tunguska destroyed Tall el-Hammam at ~1650 BCE.

To compare Tunguska to an airburst at Tall el-Hammam, we superimposed the ~2000 km² area of 80 million fallen trees at Tunguska over the Dead Sea area at an exact comparative scale (Fig. 52). The Tunguska footprint would cover about one-third of the north end of the Dead Sea and most of the plain of the Jordan Valley, including Tall el-Hammam, Jericho, and other MB II cities. This map is shown for comparison only and is not intended to represent the proposed Tall el-Hammam impact event. Even so, it does indicate that if a relatively small Tunguska-scale cosmic event occurred over the Jordan Valley, the detonation and ensuing blast wave would have been energetic enough to have caused widespread destruction.

Footnotes

65. Florenskiy, K. (1965) Preliminary results from the 1961 combined Tunguska meteorite expedition. Meteoritica XXIII, 3–37.

67. Vannucchi, P., Morgan, J. P., Della Lunga, D., Andronicos, C. L. & Morgan, W. J. (2015) Direct evidence of ancient shock metamorphism at the site of the 1908 Tunguska event. Earth and Planetary Science Letters 409, 168–174.

142. Jenniskens, P., Popova, O. P., Glazachev, D. O., Podobnaya, E. D. & Kartashova, A. P. (2019) Tunguska eyewitness accounts, injuries, and casualties. Icarus 327, 4–18.

162. Svetsov, V. (1996) Total ablation of the debris from the 1908 Tunguska explosion. Nature 383, 697–699.

163. Kirova, O. (1965) Scattered matter from the area of fall of the Tunguska cometary meteorite. Annals of the New York Academy of Sciences 119, 235–242.

178. Brazo, M. W. & Austin, S. A. (1982) The Tunguska explosion of 1908. Origins 9, 82–93.

179. Wolbach, W. S. et al. (2018) Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ∼12,800 years ago. 2. Lake, marine, and terrestrial sediments. Journal of Geology 126, 185–205.

180. Robertson, D. K. & Mathias, D. L. (2019) Hydrocode simulations of asteroid airbursts and constraints for Tunguska. Icarus 327, 36–47.

181. Kletetschka, G., Procházka, V., Fantucci, R. & Trojek, T. (2017) Survival response of Larix sibirica to the Tunguska explosion. Tree-Ring Research 73, 75–90.

182. Zlobin, A. E. (2013) Discovery of probably Tunguska meteorites at the bottom of Khushmo river’s shoal. arXiv preprint arXiv:1304.8070.

183. Kirova, O. & Zaslavskaya, N. (1966) Data characterizing the dispersed matter as recovered from the area of fall of the Tunguska meteorite. Meteoritika 27, 119–127.

184. Vishnevsky, S. & Raitala, J. (2000) Impact diamonds as indicators of shock metamorphism in strongly-reworked Pre-Cambrian impactites. In Impacts and the Early Earth, 229–247.

185. Kvasnitsa, V. et al. (1979) High-pressure carbon polymorphs in the peats of Tunguska catastrophe region. Dopovidi Akademii Nauk Ukrainskoi RSR, 999–1004.

186. Hryanina, L. (1999) The bouquet of the meteorite craters in the epicentre of Tunguska impact 1908. In Lunar and Planetary Science Conference, abstract 1186.

187. Korina, M. et al. Iridium distribution in the peat layers from area of Tunguska event. In Lunar and Planetary Science Conference.

188. LeMaire, T. R. (1980) Stones from the stars: the unresolved mysteries of meteorites. Prentice Hall.

Hypothetical Tunguska-class airburst near Tall el-Hammam

from Bunch et al. (2021:54-56)

Hypothetical Tunguska-class airburst near Tall el-Hammam. To estimate the airburst effects of a hypothetical impactor near Tall el-Hammam, we modeled a range of possible impactor diameters using the online Impact Calculator created by impact experts, Melosh et al. ^189,190. We present the results in Supporting Information, Tables S10–S11 as just two of many possible scenarios with large uncertainties^189,190. We are not suggesting that these hypothetical models represent what occurred at Tall el-Hammam because there is insufficient evidence to do so. Nevertheless, the calculations demonstrate that 12- to 23-megaton Tunguska-like airbursts can theoretically account for all the evidence observed at Tall el-Hammam.

According to the Impact Calculator, a stony meteorite, descending at a 45° incidence angle would explode above a sedimentary surface ~5 km southwest of Tall el-Hammam. We consider two plausible impactor sizes of 60 m and 75 m in diameter, providing bounds for the impact scenarios. An object larger than approximately 80 m would likely excavate a significant crater nearly a km in diameter, and so, seems unlikely, since no craters are visible in the Jordan Valley.

At the low end of the impactor size range, a 60-m object would detonate at an altitude of 4.7 km with a yield of ~12 MT, producing 917 km/h (570 mph) windspeeds 5 km away at Tall el-Hammam (Supporting Information, Table S10). At the high end of the range, a 75-m diameter object would detonate at an altitude of 1.3 km with a yield of ~23 MT, producing 1200-km/h (740 mph) windspeeds 5 km away at Tall el-Hammam, far greater than the largest Category-5 tornado ever recorded (~512 km/h = 318 mph) with a theoretical peak overpressure of ~2.5 bars (35 psi). Such wind speeds and pressures are greater than the tensile strength for adobe-style mudbricks of 0.12 MPa (17 psi) and flexural strengths of 0.17 MPa (25 psi)^191–194, exceeding the pressure needed to demolish and pulverize mudbrick walls. Those pressures even exceed the destruction limits of modern buildings of reinforced concrete. Pressures of only ~0.14 MPa (20 psi) result in a >99% human fatality rate.

In addition, the Tunguska airburst produced a seismic shock of ~5.0 on the Richter scale¹⁷⁸, and an impact-related earthquake of similar magnitude at Tall el-Hammam would have caused severe damage to the mudbrick walls of the city. For both size impactors, no single, large crater would form, but multiple large-to-small fragments would likely hit the surface, possibly forming small, shallow craters that may have been filled over time by wind and water.

At Jericho, ~15 km away from the center of the 75-m airburst, Category-3 hurricane wind velocities would have reached 216 km/h (134 mph) (Supporting Information, Table S11). For the 60-m impactor, windspeeds would have reached 237 km/h (147 mph), equivalent to an EF-3 tornado and powerful enough to shear and collapse mudbrick walls¹⁹². This is consistent with the estimated range of Tunguska wind velocities of ~40–70 m/s (144–250 km/h), a range equivalent to EF-3 through EF-5 tornadoes ¹⁸⁰.

Based on atomic testing and Tunguska, the fireball of both sizes of impactors is estimated to have expanded to ~1 km in diameter¹⁹⁵ and reached temperatures exceeding 300,000 °C in the center¹⁷⁵, many times higher than the surface of the sun (5500 °C). Both impactors would emit an intense thermal pulse (>45 cal/cm²) that radiates at the speed of light, providing enough heat to melt silicate and other materials^162,175. Temperatures would remain higher than the melting point of quartz (1713 °C) for >25 s ¹⁷⁵, sufficient to produce meltglass. As the base surge (shock wave) propagates outward for a few seconds, it also provides sufficient heat to melt the surfaces of mudbricks, pottery, roofing clay, and plaster^196,197.

The physical evidence from Tall el-Hammam suggests that ground temperatures briefly rose above 1850 °C, setting flammable materials on fire. These temperatures are far above ~150 °C that is considered lethal for humans, leading to a nearly 100% fatality rate of exposed humans ¹⁹⁴. In summary, the impact models that range from 12 to 23 megatons presented in Supporting Information, Tables S10, S11 are consistent with the observed evidence at Tall el-Hammam. The damage at Tall el-Hammam appears similar to but higher than that of the ~5-megaton airburst at Tunguska, Siberia in 1908.

A supercomputer-generated model of a hypothetical 15-megaton airburst was developed at Sandia National Laboratories by Boslough¹⁹⁷ (Fig. 53) and shows conditions that are more energetic than for the 5-megaton Tunguska model also discussed by Boslough¹⁹⁷. In our study, we propose two models for the Tall el-Hammam event that are also larger than estimated for Tunguska, a 12- and a 23-megaton model. For details, see Supporting Information, Tables S10–S11.

In summary, when a bolide as large as that proposed for Tall el-Hammam explodes in the atmosphere, we posit that a high-temperature jet reaches Earth’s surface at high velocity, excavates unconsolidated sediment, and expands radially outward in what is sometimes called a ‘base surge’. Surface temperatures rise higher than the melting points of silica-rich materials, and the surge’s radial velocity can exceed the speed of sound (1225 km/h or 761 mph). Radiative and convective heating can transform surface and excavated materials into meltglass¹⁰¹. Svetsov¹⁶² computer-modeled the airburst of an 80-m-wide impactor and found that radiative fluxes from the blast were sufficiently high to melt ~0.5 cm of surface sediment at >1700 °C for a duration of ~20 s. This closely matches the half-centimeter-thick melting of mudbricks, pottery, and roofing clay observed at Tall el-Hammam, making it possible that an airburst occurred that was larger than at Tunguska. The modeled scenarios account for all the evidence, including the destruction of thick mudbrick walls at Tall el-Hammam and Jericho (Table 2).

Footnotes

101. Boslough, M. et al. (2012) Arguments and evidence against a Younger Dryas impact event. In Climates, Landscapes, Civilizations, Geophysical Monograph Series Vol. 198, 13–26. American Geophysical Union.

162. Svetsov, V. (1996) Total ablation of the debris from the 1908 Tunguska explosion. Nature 383, 697–699.

175. Glasstone, S. & Dolan, P. J. (1977) The Effects of Nuclear Weapons, third edition. U.S. Government Printing Office.

178. Brazo, M. W. & Austin, S. A. (1982) The Tunguska explosion of 1908. Origins 9, 82–93.

189. Collins, G. S., Melosh, H. J. & Marcus, R. (2005) Earth impact effects program: A web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth. Meteoritics & Planetary Science 40, 817–840.

190. Collins, G. S., Melosh, H. J. & Marcus, R. (2005) Earth impact effects program

191. Clifton, J. R. & Davis, F. L. (1979) Mechanical properties of adobe, Vol. 13. National Bureau of Standards.

192. Torrealva, D., Cerrón, C. & Espinoza, Y. Shear and out-of-plane bending strength of adobe walls externally reinforced with polypropylene grids. In 14th World Conference on Earthquake Engineering, Beijing, 12–17.

193. Silveira, D. et al. (2012) Mechanical properties of adobe bricks in ancient constructions. Construction and Building Materials 28, 36–44.

194. Zipf, R. & Cashdollar, K. (2010) Explosions and refuge chambers: Effects of blast pressure on structures and the human body.

195. Alekseev, V., Konkashbaev, I. & Konkashbaev, I. (1998) Possible explanation of total ablation of the 1908 Tunguska asteroid.

196. Boslough, M. Computational modeling of low-altitude airbursts. In AGU Fall Meeting Abstracts, U21E-03.

197. Boslough, M. Airburst modeling. In First International Workshop on Potentially Hazardous Asteroids Characterization, Atmospheric Entry and Risk Assessment. Sandia National Laboratories.

Conclusions

from Bunch et al. (2021:56-57)

An unusual 3600-year-old charcoal-rich destruction layer at Tall el-Hammam marks the sudden abandonment of a Middle-Bronze-Age urban center in the Jordan Valley close to the north end of the Dead Sea. Across the 30-km-wide lower Jordan Valley, 15 other cities and >100 smaller villages were simultaneously abandoned at the end of the Middle Bronze Age to remain largely uninhabited for ~300–600 years. The remains of this ancient city and adjacent areas appear to be unique compared with those of other times, pointing to the occurrence of some highly unusual catastrophic event. The primary purpose of our research here has been to attempt to resolve this mystery.

An early crucial clue in this investigation was the discovery of highly vesicular potsherds in the debris matrix that appeared to have melted at high temperatures but with no clear evidence for a formation mechanism. This first discovery led to some general observations about the uniqueness of destruction layer debris, e.g., its unusual, high-temperature characteristics and its consistent SW-to-NE orientation. The site excavators speculated that the cause of the destruction may have been a cosmic airburst/impact, but they could not eliminate other potential mechanisms, including those related to warfare, volcanism, and tectonism.

These early observations stimulated our extensive investigation of the characteristics of the city’s MB II destruction layer. We conducted many comprehensive, advanced, and quantitative investigations and analyses in attempting to distinguish among several potential formation mechanisms. Any plausible solution needed to be consistent with collectively explaining the extensive lines of evidence that suggested anomalously high-velocity winds, high temperatures, and high pressures associated with this destruction.

We investigated 14 major lines of evidence to investigate this unusual event:

shocked quartz grains that formed at pressures of ~5–10 GPa

vesicular pottery that melted at >1500 °C

mudbricks and roofing clay that melted at >1400 °C

high salt concentrations in sediment, including melted KCl and NaCl incorporated into melted mudbricks

diamond-like carbon (diamonoids) that formed at high pressure and temperature

soot, charcoal and ash, indicating high-temperature fires

Fe- and Si-rich spherules, some of which melted at >1590 °C

platinum, melted at ~1768 °C

iridium at ~2466 °C

zircon at >1687 °C

chromite at >1590 °C

titanomagnetite at >1550 °C

quartz at 1713 °C

low remanent magnetism, a counter- indicator of lightning strikes

We considered and dismissed 8 of 10 potential processes (Table 3), including volcanism, warfare, and tectonism, that can account for at least some but not all of the evidence. We conclude that the only plausible formation mechanism that can account for the entire range of evidence in Table 3 is a crater- forming impact or a cosmic airburst, most likely somewhat larger than the 22-megaton airburst at Tunguska, Siberia in 1908. The data also suggest an airburst occurred a few kilometers SW of Tall el-Hammam causing, in rapid succession, a high-temperature thermal pulse from the fireball that melted exposed materials, including roofing clay, mudbricks, and pottery. This was followed by a high-temperature, hypervelocity blast wave that demolished and pulverized mudbrick walls across the city, leveling the city, and causing extensive human mortality. An important observation is that although local sediment can melt at ~1300 °C, that is a minimum temperature but not a maximum one, a conclusion that is supported by the presence of embedded minerals that melted at temperatures of up to ~2500 °C. In addition, anomalously high salt content in the debris matrix is consistent with an aerial detonation above high-salinity sediments near the Jordan River or above the hypersaline Dead Sea. This event, in turn, distributed salt across the region, severely limiting regional agricultural development for up to ~600 years.

Regarding this proposed airburst, an eyewitness description of this 3600-year-old catastrophic event may have been passed down as an oral tradition that eventually became the written biblical account about the destruction of Sodom. There are no known ancient writings or books of the Bible, other than Genesis, that describe what could be construed as the destruction of a city by an airburst/impact event. This airburst/impact hypothesis would make Tall el-Hammam the second oldest known city/town to have been destroyed by an airburst/impact event that produced extensive human casualties, after Abu Hureyra, Syria at ~12,800 cal BP¹⁷. Similarly small but devastating cosmic events are expected to recur every few thousand years¹⁸⁹, and although the risk is low, the potential damage is exceedingly high, putting Earth’s cities at risk and encouraging mitigation strategies.

Footnotes

17. Moore, A. M. T. et al. (2020) Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): High-temperature melting at >2200 °C. Scientific Reports

189. Collins, G. S., Melosh, H. J. & Marcus, R. (2005) Earth impact effects program: A web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth. Meteoritics & Planetary Science 40, 817–840.

Methods

Optical and electron microscopy

from Bunch et al. (2021:57)

Optical and electron microscopy. Samples were processed and analyzed using previously published protocol^72,75,76,81. After size-sorting with multiple screens (American Society for Testing and Materials) ranging from 4.75 mm to 53 µm, spherules and meltglass were examined using optical microscopy and electron microscopy. SEM–EDS analyses were conducted in low-vacuum mode using a JEOL-6000 SEM system and a ThermoFisher Apreo 2. Using SEM–EDS, we manually selected for detection of Fe, Ni, Mo, Ru, Rh, Pd, Os, Ir, and Pt, if present, with uncertainties of approximately ±100% for concentrations <1.0 wt.% and ±10% for larger concentrations. Measurements and analyses were performed by T.D.B., Gary Chandler, M.A.L, A.V.A., T.E.B., J.H.W., C.M., D.B., K.L., and A.W.

Footnotes

72. Firestone, R. B. et al. (2007) Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Sciences 104, 16016–16021.

75. Israde-Alcántara, I. et al. (2012) Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis. Proceedings of the National Academy of Sciences 109, E738–E747.

76. LeCompte, M. A. et al. (2012) Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis. Proceedings of the National Academy of Sciences 109, E2960–E2969.

81. Bunch, T. E. et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proceedings of the National Academy of Sciences 109, E1903–E1912.

Shocked quartz analyses

from Bunch et al. (2021:57)

Shocked quartz analyses

Sediment was treated with HCl to remove carbonates.

Sedimentary grains were wet-sieved and sorted to ≥150 µm and ≤850 µm.

Mixed grains were embedded in blue-tinted epoxy on 26×47×1 mm slides for better visibility; thin-sectioned to ~30 µm; and highly polished for microprobe analyses at Spectrum Petrographics http://www.petrography.com/ No cover slide was used.

Next, the slides were etched by immersion for ~1–2 min in a 30% solution of hydrofluoric acid (HF) liquid or alternately, exposed to HF vapor for ~1.5 min to dissolve amorphous quartz and make any lamellae more visible. The vapor produced more consistent results.

After treatment with liquid HF, we performed a dH2O rinse; neutralized with 5% sodium carbonate solution; rinse with dH2O again; then treated with 5% HCl to removed carbonates. After treatment with HF vapor, we performed a dH2O rinse.

Candidate grains were identified on the polished slides using optical microscopy (transmitted light, reflected light, and epi-illumination under both plane and crossed polarization).

The compositions of candidate grains were then investigated using SEM–EDS.

They were also examined using a cathodoluminescence detector (CL). Analyses were performed on uncoated thin sections in low-vacuum mode on a ThermoFisher Apreo 2 SEM. CL images were acquired at ~10 mm working distance using 10 kV and 3.2 nA of beam current, with 50 Pa of chamber pressure to balance charge. Individual images using red, blue, and green wavelength filters on the CL detector were acquired and composited to form the final CL images.

The relative angles of lamellae on candidate grains were measured using a Leitz universal stage mounted onto a Leitz polarizing microscope. The accuracy of U-stage measurements is estimated at ±5°.

Finally, the relative angles of lamellae to the c axis were compared to known crystallographic axes of quartz and plotted using a computer program, A.N.I.E, Automated Numerical Index Executor⁵⁵. Analyses were performed by K.L., A.W., M.A.L., A.V.A., and T.E.B.

Footnotes

55. Huber, M. S., Ferriere, L., Losiak, A. & Koeberl, C. (2011) ANIE: A mathematical algorithm for automated indexing of planar deformation features in quartz grains. Meteoritics & Planetary Science 46, 1418–1424. https://doi.org/10.1111/j.1945-5100.2011.01234.x

Electron microprobe analyses

from Bunch et al. (2021:57)

Electron microprobe analyses. Standard practices were followed for all samples investigated by electron microprobe. Selected samples of melted pottery were embedded in epoxy, mounted to 25×51×1 mm slides, and polished to a microprobe finish at a thickness of ~30 µm. Analyses were performed by Nelia Dunbar and T.D.B.

Neutron activation analysis

from Bunch et al. (2021:57)

Neutron activation analysis. Sediment samples were analyzed by ActLabs, Canada, using INAA to measure elemental abundances. For 56 elements, including Pt, Pd, Au, along with LOI, and salinity, bulk sediment samples of ~50 g each and magnetic fractions of ~1 g were analyzed using INAA, fire assay, and/or inductively coupled plasma mass spectrometry (ICP-MS) with a lower detection limit of 0.1 parts per billion (ppb). The accuracy of the laboratory results was verified with blanks and known standards.

Heating experiments

from Bunch et al. (2021:57)

Heating experiments. For the furnace experiments, a 26-mg powdered sample of unmelted Tall el-Hammam pottery was heated at 10 °C/min under argon purge using simultaneous Differential Scanning Calorimetry with Thermogravimetric Analysis (DSC-TGA). The cooled sample was investigated for signs of melting using optical microscopy. Experiments were performed by Allison Sikes, Bhavesh Patel, and M.P.

Remanent magnetism

from Bunch et al. (2021:57)

Remanent magnetism. Two pottery samples from Tall el-Hammam were weighed and affixed to a holder designed to measure the variation of the magnetization vector through stepwise laboratory-induced demagnetization in three perpendicular axes. The remanent magnetism instrument measures weak magnetic fields enabled by a superconducting quantum interference device containing Josephson junctions made by 2G Enterprises. The noise level of this instrument was 1e−8 A/m of the measured magnetic moment. The magnetic acquisition was acquired with pulse magnetizer ASC Model IM-10-30. G.K. performed the analyses.

Diamonoids and diamond-like carbon

from Bunch et al. (2021:58)

Diamonoids and diamond-like carbon. A standard protocol used to isolate nanodiamonds and other acid-resistant species of carbon has been developed and used successfully at several dozen sites³¹. For this study, there was one modification: diamond-containing residues were treated with sulfuric acid following their extraction to dissolve gypsum (CaSO₄·2H₂O) to release potentially encapsulated diamonds. Details can be found in Supporting Information, Methods S1 and Fig. S10. Images were acquired using transmission electron microscopy (TEM). Extractions were conducted by W.S.W. and J.K.

Footnotes

31. Kinzie, C. R. et al. (2014) Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 cal BP. Journal of Geology 122, 475–506.

Soot analyses

from Bunch et al. (2021:58)

Soot analyses. Soot carbon was extracted from sediment samples following a chemothermal oxidation procedure (CTO-375)¹⁹⁸. Samples were demineralized, sequentially at 0.2, 2, and 6 N HCl until effervescence ceased, and then dried. Dried samples were manually ground in a mortar and pestle to fine dust, and then thermally oxidized in a muffle furnace. The furnace was set to a 24-h cycle, with 6 h to ramp the temperature up to 375 °C, where it was held for twelve hours, followed by a six-hour cool-down period. The isolated residue is operationally defined as soot. Soot samples were ground using a mortar and pestle, and then gravimetrically placed in small tin capsules which were sent to the UC Davis Stable Isotope Facility for quantification of carbon abundance and its stable isotopic signature. Experiments were conducted by S.M. and A. M-B.

Footnotes

198. Gustafsson, Ö. et al. (2001) Evaluation of a protocol for the quantification of black carbon in sediments. Global Biogeochemical Cycles 15, 881–890.

Aciniform carbon (AC)

from Bunch et al. (2021:58)

Aciniform carbon (AC). A standard protocol was used to extract AC/soot from bulk sediment^{31,179,199–202}. The process consists of multiple steps:

Demineralization through multiple treatments of hydrofluoric acid (HF) and hydrochloric acid (HCl);

Oxidation to separate organic material from elemental carbon using acidic potassium dichromate;

SEM analysis to differentiate between AC/soot and non-soot carbon;

Examination of micrographs to quantify soot vs non-soot carbon abundances using particle size analysis. Experiments were conducted by W.S.W. and J.K.

Footnotes

31. Kinzie, C. R. et al. (2014) Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 cal BP. Journal of Geology 122, 475–506.

179. Wolbach, W. S. et al. (2018) Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ∼12,800 years ago. 2. Lake, marine, and terrestrial sediments. Journal of Geology 126, 185–205.

199. Wolbach, W. S., Gilmour, I. & Anders, E. (1990) Major wildfires at the Cretaceous/Tertiary boundary. Geological Society of America Special Paper 247, 391–400.

200. Wolbach, W. S., Lewis, R. S. & Anders, E. (1985) Cretaceous extinctions: Evidence for wildfires and search for meteoritic material. Science 230, 167–170.

201. Wolbach, W. S. et al. (2018) Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ∼12,800 years ago. 1. Ice cores and glaciers. Journal of Geology 126, 165–184.

202. Wolbach, W. S., Gilmour, I., Anders, E., Orth, C. J. & Brooks, R. R. (1988) Global fire at the Cretaceous–Tertiary boundary. Nature 334, 665–669.

Bayesian analyses of radiocarbon dates

from Bunch et al. (2021:58)

Bayesian analyses of radiocarbon dates. There are two functions in OxCal that are used for combining dates from a single inferred event. The ‘R_Combine’ function is used to combine two or more radiocarbon dates from the same source, e.g., a single skeleton^203,204. The ‘Combine’ function is used to combine two or more radiocarbon dates from different sources that are believed to be coeval, e.g., the date that beams were used to build a cathedral^203,204. The ‘Combine’ routine is the one used in Bunch et al., because there were different radiocarbon sources, e.g., charred palace beams and charred seeds. The presence of tens of thousands of pieces of charcoal, wood, melted mudbricks, melted pottery, and melted spherules randomly mixed throughout a single unstratified, unconsolidated stratum strongly supports the hypothesis that they represent a single city-wide episode of biomass burning. Thus, the ‘Combine’ function is the appropriate OxCal routine to use.

Footnotes

203. Ramsey, C. B. (2013) Analysis operations and models

204. Ramsey, C. B. (2013) Analysis examples

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from Bunch et al. (2021)

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Bunch et al. (2023) Author Correction

from Bunch et al. (2023)

Correction to: Scientific Reports https://doi.org/10.1038/s41598-021-97778-3, published online 20 September 2021

The original version of this Article contained errors.

2021

The original version of this Article contained errors. Some of the figure panels have been manipulated to remove the features irrelevant to the scientific content depicted in those (e.g. measuring tape, previous image labels, visible fingers etc.). The Authors recognise that this level of manipulation was inappropriate, and provide original images. As a result, the following panels were corrected and the original versions of the figures containing these panels are shown below for the record: Figure 3, Figures 4C & 4D, Figures 7C & 7D, Figures 8A & 8C, Figures 10A-C, Figures 11A-C, Figures 13D, 13F & 13H, Figure 14A & 14C, Figures 15A & 15B, Figures 18A & 18D, Figure 21A, Figures 22A, 22C & 22E, Figures 23A, 23C & 23F, all panels in Figure 25, Figures 26A & 26B, all panels in Figure 28, Figures 29B, 29D, and 29E, all panels in Figure 30, Figure 31A, Figure 32A, 32C, 32D & 32F, Figures 33A & 33B, all panels in Figure 34, Figures 38B-D, Figure 39A, Figure 40A, Figures 41A & 41C, Figures 42A & 42C, Figure 43, Figure 44C, Figure 45C, Figure 46C, and Figure 47B & 47C.

Additionally, scales were re-adjusted in the following panels: Figure 4C, Figures 11A, 11C & 11D, and Figure 26A. A number of panels was rotated 180 degrees so that original labels are not oriented upside down; this affects Figure 13H, Figure 22B, Figures 25C, 25E, 25F, & 25K, Figure 32A & 32B, Figure 34E, Figures 38C & 38F. Panels 14A & 14B had colour adjusted – these panels now show original images. Position of panels in Figure 51 was re-adjusted.

Finally, panel 15b was horizontally flipped in relation to the original and had the arrow pointing north obscured. It has now been replaced with a correct image.

Original versions of all affected figures are reproduced below for the record.

Additionally, a further clarification of how the OxCal tool was used are now included in the paper. A new subsection called ‘Bayesian analyses of radiocarbon dates’ was added at the end of the Methods section. This subsection includes two new references, References 203 and 204, which are now added to the Reference list in the published Article:

“There are two functions in OxCal that are used for combining dates from a single inferred event. The ‘R_ Combine’ function is used to combine two or more radiocarbon dates from the same source, e.g., a single skeleton203,204. The ‘Combine’ function is used to combine two or more radiocarbon dates from different sources that are believed to be coeval, e.g., the date that beams were used to build a cathedral203,204. The ‘Combine’ routine is the one used in Bunch et al., because there were different radiocarbon sources, e.g., charred palace beams and charred seeds. The presence of tens of thousands of pieces of charcoal, wood, melted mudbricks, melted pottery, and melted spherules randomly mixed throughout a single unstratified, unconsolidated stratum strongly supports the hypothesis that they represent a single city-wide episode of biomass burning. Thus, the ‘Combine’ function is the appropriate OxCal routine to use.”

The Competing Interests section was updated and now reads:

“T.E.B., M.A.L., J.H.W., W.S.W., G.H., C.R.M., J.P.K., and A.W. volunteer their time as cofounders and/or directors of the Comet Research Group (CRG), a 501(c)(3) nonprofit organization. CRG received donations from the public and contributed funding for equipment, supplies, and scientific analyses. T.E.B., M.A.L., J.H.W., W.S.W., G.H., C.R.M., J.P.K., and A.W. receive no salaries, compensation, stock, or any other financial benefits from CRG, except that M.A.L., G.H., and A.W. realize tax benefits from donations to CRG. In some cases, co-authors have been compensated for out-of-pocket expenses, such as airfare, that are directly related to the TeH research.

P.J.S. volunteers his time and receives no salary from Trinity Southwest University (TSU), a 501(c)(3) nonprofit organization. TSU received donations and contributed support, supplies, equipment, and funding for TeH Excavation Project. P.J.S. was reimbursed by Trinity Southwest University for his hotel room while in Jordan but not for other out-of-pocket expenses.

P.J.S. is the author of two books related to TeH.

A.W. is the author of a book unrelated to TeH.

A.V.A., C.M., D.B., E.C.S., G.K., J.K., K.L., M.C.L.P., R.E.H., S.M., T.D.B., and T.W. received salaries, supplies, equipment, and/or funding for scientific analyses from their respective universities/ organizations, which, due to the worldwide publicity, possibly stand to benefit from increased donations and student enrollments.

All co-authors have not yet but may receive reimbursements for attending symposia on this research from their respective organizations. All co-authors were involved in various aspects of conceptualization, design, data collection, analysis, the decision to publish, and/or preparation of the manuscript.”

Finally, the beginning of the Acknowledgements section was updated,

“We gratefully acknowledge the invaluable assistance of the senior staff at Tall el-Hammam: Director, Steven Collins; Assistant Director, Gary A. Byers, and Assistant Director, Carrol M. Kobs.” now reads:

“We gratefully acknowledge the invaluable assistance of the senior staff at Tall el-Hammam: Director, Steven Collins; Assistant Director, Gary A. Byers, and Assistant Director, Carrol M. Kobs. Additionally, we thank Daniel Galassini, Michael Luddeni, Brandy Forrest, James Barber, and Sultan Madi, who took the site excavation photographs for the Tall el-Hammam Excavation Project, which made them available for this study (Fig 1B, Figs 4D & 4E, Fig 6, Figs 7A & 7B, Fig 15A, and Fig 44C—Michael Luddeni, Fig 3—Daniel Galassini, Figs 7C & 7D, Fig 15B—Brandy Forrest, Fig 16A—James Barber, Figs 44A & 44B—Sultan Madi).”

The original Article has been corrected.

Jaret and Harris (2022) - A Rebuttal Letter to Bunch et al. (2021)

from Jaret and Harris (2022)

arising from : T. E. Bunch et al.; Scientific Reports https://doi.org/10.1038/s41598-021-97778-3 (2021).

In their recent Nature Scientific Reports article, Bunch et al.¹ present several observations from the geologic and archeologic record and conclude that the destruction of the Bronze Age city Tall el-Hammam was caused by a cosmic air burst. Here, we challenge their mineralogic and geochemical observations. This is important because as determined by the impact cratering community, these are the only kinds of evidence that can provide uniquely diagnostic evidence of impacts or airburst and are the only criteria currently acceptable for confirmation of impact.

Studies of confirmed and doubtful impacts and air bursts that could have affected humans have generated considerable excitement and debate over the last two decades^2,3,4,5. The excitement importantly emphasizes the critical role of geological studies in the field of planetary defense. While we welcome provocative hypotheses that implicate hypervelocity collisions in historic disasters, we must recognize that the implication for assessing future risks demands adherence to the highest burdens of evidence.

The importance of uniquely diagnostic evidence for shock metamorphism

Bunch et al.¹ however, fail to demonstrate convincing evidence of impact-shocked minerals in the proposed air burst deposit by not following well-established guidelines and criteria^{6,7,8,9,10,11,12,13}. And although the authors also report the presence of ultra-high-temperature mineral phases and geochemical enrichments in melts that often are used to distinguish impact glasses from those produced by volcanoes, lightning, and pyrometamorphism, these criteria have little meaning in the context of archeological debris where our ancestors had access to ceramic and smelting technologies. Much of the melt glass presented in their study is closely associated with pottery; many specimens are pieces of remelted ceramics like one might find in spoils and dumps; and many examples they provide to demonstrate ultra-high temperatures, such as the formation of baddeleyite rims on zircon and the embayment of refractory phases by dissolution in hot melts, are well-documented in ancient slags¹⁴. We emphasize the importance of uniquely diagnostic criteria for confirming impact or shock events. The impact materials community has outlined several criteria considered unique to impacts, and detailed what kinds of analyses are suitable for making such observations^{6,7,8,9,10,11,12}. Natural materials are complex, and so it is possible to find non-diagnostic features within bona-fide shocked materials. The converse, however, is not true. The presence of only non-diagnostic features—even if these same features sometimes occur in shock materials—is not sufficient to claim impact. Without unequivocal evidence of shock metamorphism, minerology and geochemistry that cannot be explained by human activities, or definitive remains of an extraterrestrial impactor, the Bunch et al.¹ claim that the city’s demise was the result of a cosmic catastrophe cannot be supported.

We outline below many of the ways their report fails to meet the standards required to demonstrate an extraterrestrial cause.

The putative “shocked quartz” grains do not exhibit the attributes required for shocked quartz

Their optical photomicrographs intended to illustrate planar deformation features (PDFs) do not exhibit the properties of PDFs as established by the literature^{6,7,8,9,10,11,12,13,15,16,17,18,19,20}.

Specifically, the “lamellae” in the grains are not planar, and instead pinch and swell in thickness, and have irregular spacing. These are in direct contrast to shocked quartz produced in nature, nuclear explosions, and laboratory experiments which have planar morphologies, uniform spacing, and do not change thickness^{9,10,12,15,17,19,20}^.

The authors present measurements of their “lamellae” orientation as evidence of impact origin. This is insufficient and not an accepted method for verifying authenticity of shocked quartz. In shocked quartz, PDFs occur at specific orientations and measuring their orientation is often part of the characterization process^16,21. However, simply having an orientation that is common to PDFs does not universally demonstrate a shock origin. In the presented dataset, shock lamellae cannot be distinguished from tectonic lamellae based on orientation alone. In fact, all but two of the twelve indexed “lamellae” have orientations common to frequently documented twin planes in tectonically or thermally stressed quartz. Only the (0001), or basal, orientations might be interesting, as bona fide basal Brazil twins generally are believed to be diagnostic of shock. But these are not displayed in the figures despite the author’s emphasizing the (0001) orientation in Fig. 21, which are their comparative “known airburst” grains.

Any informative value the histogram in Fig. 20 might have is further complicated by the fact that it apparently lumps multiple kinds of features (planar fractures (PFs), feather features (FFs), and PDFs) as “shock lamellae.” These features occur under different conditions, have different formation processes, and have different degrees of uniqueness to impact. For example, PDFs are recognized as unique diagnostic effects of shock metamorphism, whereas FFs are believed to be associated with impact-induced shearing, and PFs may form across a wide range of impact and non-impact conditions. Basal PDFs (Brazil twins) and basal PFs can lead to very different conclusions. But from the data presented, we do not have any way to determine which of these features are present in this study. Also, the putative feather features, apparently only one occurrence illustrated in Fig. 18e, do not conform to the definition of feather features. Feather features intersect the associated fracture at acute angles²². The faint features shown in Fig. 18e are at right angles to the fracture, a very common microfabric in tectonically deformed quartz.

The authors state that “Tall el-Hammam grains pass four main tests that confirm impact-shock and contra-indicate tectonic lamellae: (i) they are crystallographically aligned; (ii) some are parallel to the c-axis; (iii) all are visible in SEM imaging and epi-illumination indicating presence of amorphous quartz; and (iv) all are non-luminescent (black) or red under CL imaging.” None of these are unique tests for shocked quartz, nor are these the criteria established by the impact community for identifying shocked quartz^8,17,18. Lamellae occurring parallel to the c-axis are common in natural and experimental tectonic deformation which form lamellae parallel to c in response to slip along the (0001) plane²³. Electron beam imaging (including CL imaging) are frequently used in support of optical microscopy to characterize independently verified PDFs, but cannot alone be seen as diagnostic. Moreover, the CL images in Fig. 18 showing lamellae that—despite being generally planar—occur as thick, discontinuous, widely spaced lenses of variable grayscale precisely match the description of tectonic lamellae provided by Hamers and Drury²⁴.

Bunch et al.¹ also claim that “SEM analyses of HF-etched grains allow for unambiguous visual distinction between glass-filled PDFs and glass-free tectonic lamellae, which are not visible on the surface of sectioned grains” as justification that their features are shock-produced. While HF etching can enhance the appearance of PDFs, true PDFs are always visible optically without etching. Etching can be problematic because non-shock features such as twin planes, (eg., Dauphine, Brazil, etc.) and lattice dislocations, which otherwise are invisible in optical microscopy will appear when grains are etched by HF²⁵. Dauphine twins can result from thermal stress at the alpha–beta quartz transition (573 °C), and by necessity should form in quartz grains encased in high temperature melt. Consequently, the argument that etching uniquely identifies shock features is incorrect.

Extraterrestrial geochemistry as evidence of impact

The geochemical data presented is not adequate or sufficient for confirming presence of extraterrestrial material

In addition to petrographic observations of shock metamorphism, geochemical signatures of meteoritic material, such as enrichments in Platinum Group Elements (PGEs), can be accepted as evidence of impact^26,27,28. These highly siderophile elements are heavily sequestered in the core and have low abundance in crustal rocks but have high concentrations in most extraterrestrial materials. However, the presence of an anomaly in just one PGE alone is not enough to uniquely identify an impact origin. While PGE concentrations in surficial rocks typically are in the parts per trillion (ppt) range, environments exist on Earth where Pt and/or Ir concentrations can reach several parts per billion (ppb) such as in deep-deposited organic shales, surficial biomass deposits²⁹, mantle xenoliths or deep-sourced volcanic rocks, and in some slags derived from industrial processing of ores. Therefore, a broader geologic context is necessary for interpretations. To convincingly show evidence of meteoritic components, the full suite of PGEs should match known meteorite groups ²⁸. The PGE data presented here is limited to only Pt and Ir, which is not sufficient to indicate impact origin. Additionally, PGE concentrations can be notoriously challenging to measure^28,29,30 unless using either Instrumental Neutron Activation Analysis (INNA), or highly standardized (fire assay) plasma mass spectrometry. Bunch et al.¹ use electron microscopy energy dispersive spectrometry (EDS), which has been shown to be inadequate and overestimates Pt abundances by up to a factor of 4³⁰. This is particularly problematic at low accelerating voltages, and at the 10 kV voltage used in this study, there is not enough energy to separate the PGE peaks in EDS.

In summary, we feel that the observations and data presented here do not meet the well-established criteria for documenting evidence of an extraterrestrial event. The limited quartz grains presented do not contain convincing of a hypervelocity shock. Claims of ultra-high temperature melt formation and meteoritic geochemistry have not been uniquely demonstrated to be the product of exogenic process. Recognizing impacts and air burst events in the recent geologic record, however, is an important component of planetary defense, and understanding the interaction between these events and civilizations is an exciting and critical aspect of the field. This work does however, demonstrate the difficulty of relying upon mineralogical and geochemical criteria that can be significantly affected by human technology when analyzing materials in the time period after the development of human-initiated industrial and ritual based melting.

Retraction Note for Bunch et al. (2025)

from nature.com

Retraction Note: A Tunguska sized airburst destroyed Tall el-Hammam a Middle Bronze Age city in the Jordan Valley near the Dead Sea

Scientific Reports volume 15, Article number: 14291 (2025)

Retraction of: Scientific Reports https://doi.org/10.1038/s41598-021-97778-3, published online 20 September 2021

The Editors have retracted this Article.

Following publication of this Article concerns have been raised by Jaret & Harris1 about errors in methodology, analyses, and interpretation of the mineralogic and geochemical data in the Article. In addition, Boslough & Bruno2 show that comparisons between the Tall el-Hammam site and the Tunguska event are not adequately substantiated, as a result of errors propagated from the original sources that overestimated the temperature, wind speeds, and impact of the air blast at Tunguska.

Therefore, the claims that an airburst event destroyed the Middle Bronze Age city of Tall el-Hammam appear to not be sufficiently supported by the data in the Article. Given these concerns, the Editors no longer have confidence that the conclusions presented are reliable.

Malcolm A. LeCompte, T. David Burleigh, Robert E. Hermes, Wendy S. Wolbach, Gunther Kletetschka, Timothy Witwer, George A. Howard, Christopher R. Moore, James P. Kennett, Allen West, and Phillip J. Silvia disagree with the retraction. A. Victor Adedeji, James H. Wittke, Charles Mooney, Dale Batchelor, Joel Kathan, Mark C. L. Patterson, Edward C. Swindel, Siddhartha Mitra, and Kurt Langworthy did not respond to the Editors’ correspondence about the retraction. Ted E. Bunch is deceased.

References

Jaret, S. J. & Scott Harris, R. No mineralogic or geochemical evidence of impact at Tall el-Hammam, a Middle Bronze Age city in the Jordan Valley near the Dead Sea. Sci. Rep. 12, 5189.

Boslough, M. & Bruno, A. Misunderstandings about the Tunguska event, shock wave physics, and airbursts have resulted in misinterpretations of evidence at Tall el-Hammam. Sci. Rep. 15, 13869. (2025).

Archaeoseismic Seismic Effects

City Wall Earthquake 1 - Early Bronze II/Early Bronze III Transition - ca. 2700 BCE

Effect	Location	Image(s)	Description(s)
Collapsed Walls	Fortification Walls Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015) Fig. 5.10 EB2-3 wall, gate, and street Click on image to open in a new tab Collins et al. (2015) Fig. 5.11 Isometric drawing of EB2-3 gate Click on image to open in a new tab Collins et al. (2015) Fig. 5.12 Reconstruction drawing of EB2-3 gateway Click on image to open in a new tab Collins et al. (2015)	Fig. 5.8 Fig. 5.8 Earthquake activity of EB2 and EB3 rebuild of city wall at Tall al-Hammam Click on image to open in a new tab Collins et al. (2015) Fig. 5.9 Fig. 5.9 One of Tall al-Hammam’s EB2-3 gates Click on image to open in a new tab Collins et al. (2015)	"As it happened, Tall al-Hammam’s initial city wall (EB2) enclosed at least 25 hectares which was, in turn, surrounded by agricultural settlements in close proximity. But that wall was severely damaged— probably by an earthquake—during the transition from EB2 to EB3, ca. 2700 BCE. Excavated sections of the EBA city wall reveal that the EB2 phase had only one or two course-lines of medium to large boulders running parallel to the direction of the wall at the base of the inner and outer faces. Between the outer and inner lines of boulders the 6m-thick EB2 wall consisted of mudbricks only—thus its structural vulnerability. The subsequent EB3 version of the city wall was significantly more substantial, with the installation of an all-stone foundation of small-to-medium boulders, five to six courses laid to the full 6m width." - Collins et al. (2015:xxvii) "There was, however, a disruptive event that seems to have required residents to rebuild most of the architecture across the site at about the transition from EB2 to EB3, ca. 2700 BCE (Collins et al 2011, 2009). The EB2 to EB3 architectural interface is easily seen in the construction history of Hammam’s massive city wall—from 5.2m to 6m thick—enclosing an area in excess of 25ha (more than 60 acres). At some point toward the end of EB2 or beginning of EB3, a significant earthquake occurred that (seemingly) caused extensive damage over most of the city. (See Figure 5.8.) Evidence of this disruption is clearly visible as post-quake adjustments to the city wall foundation. The original EB2 foundation consisted of one to two rows of large stones set on bedrock along the inner and outer faces, with mudbricks between to the level of the stones. While this stone and mudbrick foundation required less effort than an all-stone approach, it turned out not to be a very good idea. The earthquake did so much damage that virtually the entire city wall had to be rebuilt. The EB2 wall was deconstructed down to what remained stable—which was not much. However, the EB3 builders determined that a few sections of the EB2 foundation remained stable enough to be incorporated into the new construction. Some of the EB2 stone and mudbrick foundation was purposefully left in place, and a massive, all-stone foundation—6m thick and six courses high—was installed. But curiously, in a few places, one or two courses of EB2 mudbricks are visible on the outer face underneath the EB3 all-stone foundation. Evidence of an EB2 direct-entry gateway is still visible in Field LA (Collins et al 2011)." - Collins et al. (2015:58-59) "Following the ca. 2700 BCE earthquake damage at Tall al-Hammam—similar to the devastation at Khirbet al-Batrawy at about the same time (Nigro 2008)—its city wall was widened slightly to about 6m in order to support a taller mudbrick superstructure built upon a foundation consisting of six courses of medium-to-large fieldstones. Partial remains of the mudbrick city wall—up to a dozen courses in places—remain intact. The stone foundation is preserved in its entirety over most of the length of the southern defenses (due to its integration into the later, and much larger, MBA fortifications) (Collins et al 2011, 2009)." - Collins et al. (2015:71-73)
Collapsed Walls Fire	Residential Areas in Field LA in the Lower Tall Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015) Fig. 7.4 Tall al-Hammam-domestic architecture on the Lower Tall. Click on image to open in a new tab Collins et al. (2015) Fig. 7.6 Hammam’s Lower Tall MBA fortifications(in yellow). Click on image to open in a new tab Collins et al. (2015)	Fig. 2.5 Panoramic View of the Tall al-Hammam Excavations, LA Trench (Field LA). Click on image to open in a new tab Collins et al. (2015) Fig. 2.8 Horizontal Method at Tall al-Hammam, Field LA Click on image to open in a new tab Collins et al. (2015)	"A portion of the EB3 domestic area has been excavated directly inside the city wall near the gateway (Field LA). Apparent in all structures are the tightly knit phases of architectural evolution from EB2 and EB3, ultimately into the IBA and MBA, following the same footprints and wall lines, period to period, which is a clear indication of unbroken occupation. Ash, sometimes in remarkable quantities, is consistent throughout the EB2–3 domestic area (Field LA), further demonstrating the earthquake event that led to the houses being rebuilt." - Collins et al. (2015:71-73)

City Wall Earthquake 2 - Intermediate Bronze II/Middle Bronze I Transition - 2000-1950 BCE

Effect	Location	Image(s)	Description(s)
Collapsed Walls	Fortification Walls Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)		"The IBA fortifications were still in use at Tall al-Hammam when a major earthquake devastated the city between 2000 and 1950 BCE, probably damaging the perimeter defenses beyond repair. But no matter—it seems that the city ‘fathers’ had something else in mind all along, and this was the perfect ‘excuse’ to put their plans into motion. What they envisioned was a new style of fortification system that rose to the challenges presented by rapidly evolving methods of siege warfare—siege towers, mobile battering rams, and sapper battalions skilled in the art of breaching city walls (Burke 2008; McAllister 2008). From what source(s) their system designs originated is unclear, but the same general type of ‘ramparted’ fortifications began to be built across both the southern and northern Levant around the beginning of the Middle Bronze Age (MB1), ca. 2000–1950 BCE." - Collins et al. (2015:xxvii)

Fiery Destruction - Middle Bronze II - ca. 1650 BCE

Effect	Location	Image(s)	Description(s)
Collapsed Walls Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Site-Wide Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. 4a Map of the city (white dashing line) showing sampling locations, spanning ~1100 m Source of base image: “Tall el-Hammam”. 31° 50.483 N, 35° 40.029 E. Google Earth; CNES/ Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Click on image to open in a new tab Bunch et al. (2021) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Human bone (HB) scatter in the ashy matrix of Hammam’s MB2 destruction Click on image to open in a new tab Collins & Scott (2016) Fig. 44 Human bones in the destruction layer Photo of a disarticulated skull found near the palace on the ring road around the upper tall. The right eye socket has been crushed (orange arrow). Skull is embedded in pulverized mudbrick containing numerous charcoal fragments (yellow circles) and is stained with ash commonly found in the destruction layer (blue arrow). Te orange tint of the skull suggests it was exposed to temperatures > 200 °C141 Rear view of the same skull in panel ‘a’ (blue arrow) near the second skull (purple arrow) and numerous disarticulated, fragmented human bones (orange arrows). Charcoal fragments at yellow circles Lower torso from the ring road of lower tall (orange arrows), and other disarticulated bones. Bones show evidence of being burned (red arrows); the rest of the skeleton is dismembered and disarticulated. Hyper-fleed toes (purple arrow) are consistent with either perimortem or postmortem exposure to high temperatures Click on image to open in a new tab Bunch et al. (2021) Fig. 17 The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide). Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html). Click on image to open in a new tab Bunch et al. (2021)	Description(s) "while the majority of sites in Cisjordan and Transjordan either limped or thrived into the Late Bronze Age, MBA civilization in the S Jordan Valley, anchored by Tall el-Hammam, never saw the dawn of LB1. From that moment—toward the end of MB2—occupation in this southernmost `circle' of the Jordan Valley ceased for the next 700 years. Focused research into the phenomenon that caused this devastation is ongoing. However, it is interesting to note that an analogous event, a fiery air-blast of cosmic origin, is now suggested to have brought about the demise of Tell Leilan, Tell Hjeira, and Tell Brak in Mesopotamia ca. 4200 BCE (Courty 2008, 2001, 1998; Weiss et al 1998)" - Collins et al. (2015:175) "The destruction of Bronze Age Tall al-Hammam, toward the end of MB2, was violent. On both the Upper and Lower Talls, a 1–1.5 m layer of ash, strewn with broken pottery, mudbricks, and a grisly repertoire of charred remains, is clearly visible in all excavated areas. (See Figure 7.12.) In adjacent agricultural fields, one can easily see that the soil composition is dominated by prodigious quantities of grey ash, in contrast to the reddish-brown (Munsell: 7.5yr) color of the natural soil. Many of the foundation stones of the MBA fortifications are burnt and heat-fractured. Whatever the origin and nature of this conflagration, it was terminal. Both Tall al-Hammam and the adjacent S Jordan Valley remained unoccupied until IA2, about 700 years later. (See Figure 7.13.)" - Collins et al. (2015:181) "All Tell el-Hammam sampling profiles investigated contain an MB II burn layer that is highly complex and variable across the tall but is generally composed of three parts. The first part is the deepest one and is mainly pulverized mudbrick, mixed with larger melted and unmelted mudbrick fragments, melted and unmelted roofing clay, ash, charcoal, charred seeds, unburnt wood, burned textiles, bones, plaster fragments, broken pottery, and melted pottery. We call this the “debris matrix.” It varies in thickness up to ~1.5 m and is only occasionally missing across the entire tall. The second part, immediately above the debris matrix, is composed of thin, windblown, fine-grained laminations, including fragments of broken plaster, limestone spherules, and charcoal, radiocarbon-dated to 1650 BCE. It is not present in all locations and instead is typically found on the NE sides of SW-facing wall remnants at the top of the debris matrix. This extraordinary stratum is termed the “blow-over layer.” Nothing similar has been identified in any older or younger deposits, beginning in the Early Bronze Age and extending through the Iron Age. The third part is a charcoal-and-ash-rich stratum that we call the “dark layer,” which is found everywhere across the tall and is typically only a few centimeters thick or less. However, on the outer, southwest-facing side of the large city gate, it is ~1 m thick. Sometimes the dark layer is present on top of the blow-over layer, but other times it is the only layer found, usually resting on top of an existing interior building floor. Its depth of burial varies considerably from being near the surface on parts of the lower tall to being buried 1–4 m across most of the upper tall. The debris matrix, the blow-over, and the dark layer collectively comprise the interval of interest called the “destruction layer.”" - Bunch et al. (2021:6-8) "During 15 field seasons at Tell el-Hammam, there have been extensive excavations of ~100 squares (each ~6 × 6 m in size) spread across the upper and lower tall. On Tell el-Hammam occupational surfaces older and younger than the MB II destruction layer, whole and broken pottery were nearly always found with all fragments confined to a small area that was their “working space.” In contrast, the destruction layer exhibits a distinct orientation pattern marking the movement of objects across the MBA-age excavated floors. Out of about 2000 different vessels represented in the palace destruction matrix, most are fragmentary, and not a single one, smashed or otherwise, has been found in its “working” place on a floor or other surface. Instead, nearly all pottery vessels were broken and strewn in a narrow SW-to-NE orientation spanning up to 10 m. On the rare occasions when intact or nearly intact ceramic vessels were found, they were seldom found on the SW side of walls, but rather were protected on the NE side of walls, often tilted to the NE and embedded in the destruction matrix. For example, the excavators uncovered an MBA-age food preparation room in the palace with more than 150 separate pottery vessels (some shown in Fig. 15). Shattered MB II potsherds were strewn across the palace floors from SW to NE, nearly always located within the bottom ~20 cm of a churned-up debris matrix that ranged in thickness from 50 to 150 cm. Grains, such as barley, that had been stored in some of the pots were also distributed from SW to NE, interspersed among the trail of potsherds. In another notable example, a distinctively decorated pot was found in pieces spread narrowly across ~6 m, with the majority of its decorated fragments concentrated against the SW-facing wall of the room. Broken potsherds from at least 50 separate vessels of all sizes have been found on this surface, and all pieces were strewn in the SW-to-NE direction. Figure 15b shows three examples of shattered pots with potsherds strewn in narrow paths across >60 cm in a SW–NE orientation. Before being excavated, they were embedded in pulverized mudbrick from the destruction layer. This pattern of directionality was also observed for larger objects. Within the sealed, undisturbed MB II context of the palace, excavators uncovered a heavy saddle quern (weight: ~400 kg or 880 lb; dimensions: ~90 × 50 × 40 cm). Made of dense local stone and used for grinding grain, the quern was found toppled from its dirt pedestal and tipped on its side on the floor of a food preparation area (Fig. 15a). The geometric axis of the quern aligns with the SW–NE direction. Barley grains that had once been on top of the quern were found carbonized and strewn across the floor ~1 m to the NE between the overturned quern and the SW-facing wall, suggesting SW-to-NE movement (Fig. 15a). Radiocarbon dating of carbonized wood and grain from this floor confirms ~1650 BCE (~3600 ±50 cal BP) as the date for the destruction event. Discussion of directionality. An inferred sequence of events that produced the destruction layer (collectively the lower debris matrix, the blow-over above it, and the upper charcoal-rich dark layer) is shown in Fig. 16. Over a brief span of seconds, a high-velocity, debris-entrained shock wave arrived from the SW, demolished the mudbrick walls of the city, blew over the fallen walls, severely abrading (sand-blasting) the top surfaces, and deposited thin laminations of pulverized mudbrick, fragments of crushed building plaster, limestone spherules, ash, and charcoal, typically 20–30 cm thick (Fig. 16e). The wind demolished the portions of walls and ramparts that extended higher than several courses of mudbrick. Along interior walls, melted mudbrick, broken pottery, wall plaster, charred beams, and other interior debris were pushed against the SW-facing sides of walls that were typically 60–70 cm thick (Fig. 16c), filled the remaining space with pulverized debris (Fig. 16d), and blew the remainder off the tall to the NE. This sequence of fallen walls, capped by blow-over layers, appears to have occurred nearly instantaneously because there is no evidence of erosion or passage of time between the top dark layer, the blow-over layers, and the underlying debris matrix. Significantly, above the destruction layer, there is no evidence for extensive human occupation at Tell el-Hammam for ~600 years. Instead, gradual sediment erosion and redeposition buried the entire destruction layer. After that long hiatus, the city was only minimally rebuilt during the Iron Age and never returned to its former size and level of occupation. Evidence of directionality from SW to NE within buildings has been identified in ~100 excavated squares across the site. Directionality is indicated for up to six materials: melted pottery melted mudbricks blow-over detritus general building material seeds and grains potsherds Notably, all excavated squares, including the palace, temple, and ring road (Fig. 17), display evidence of SW–NE-trending blow-over materials, primarily composed of thinly laminated layers of pulverized mudbrick, ash, charcoal, and fragments of white plaster. Following the destruction event, archaeological evidence indicates that the city was only minimally rebuilt ~600 years later during the Iron Age. When that occurred, there is no apparent evidence that later inhabitants recycled surviving mudbricks for rebuilding the city. In any event, later structures are far too few to account for the massive number of missing mudbricks. Nearby cities were not rebuilt either, so no mudbricks from Tell el-Hammam could have been used for that purpose. Furthermore, the city foundations are sealed by pulverized mudbrick and charcoal that dates to ~1650 BCE throughout the city, indicating the destruction layer has remained undisturbed for >3600 years until modern times. In summary, the evidence is consistent with the hypothesis that the city’s mudbrick walls were pulverized by hypervelocity winds from a high-temperature event of cataclysmic proportions and the debris was blown off the tall to the NE." - Bunch et al. (2021:18-21)
Collapsed Walls Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Upper Tall Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)		Description(s) "If the MB II destruction event at Tell el-Hammam was of sufficient magnitude and abruptness to be fatal for human inhabitants, as the evidence indicates, human remains should exist in the MB II layer. Indeed, human skeletal remains of sufficient size to be positively identified were found on the upper ring road that encircled the upper tall between the MB II defensive fortification wall and the outer wall of the MB II palace. Two human skulls were found about 20 cm apart (Fig. 44a, b), adjacent to a portion of a pelvis and a likely arm bone fragment. One skull was missing the mandible, and the right orbit was crushed about 50%. The second skull fragment consisted only of the upper dentition and lower half of the right orbit. Only two or three rib fragments were found and no other long bones were recovered. The forensic evidence suggests that the two bodies may have been decapitated, dismembered, and disarticulated. The record indicates that most of the bones had been shattered into small pieces and mixed into a matrix of pulverized mudbricks. Currently, it is not possible to determine if the small bones are from humans or small mammals, but their proximity to identifiable human bones makes it most likely that they are human. If so, only ~10% of the combined original bone mass of both humans is present as observable fragments within a 75-cm radius from the skulls. The remaining 90% of the two skeletons are missing and assumed to have been destroyed and/or located further away in the sediment matrix. These skeletons were found on the roadway around the upper tall, where the road was 3–4 m wide. The top of the nearby rampart was several meters wide. The remains were found at a depth of about four meters below the modern surface, well-sealed and undisturbed beneath archaeological sterile strata. The bodies had been rapidly entombed by pulverized mudbrick containing abundant ash and charcoal. No weapons were found associated with the skeletons or evidence of damage by weapons, and neither body showed any indication of exposure to scavengers. Although humans can be mortally affected by earthquakes, volcanism, and warfare, these bone characteristics, both individually and collectively, show no evidence that these human deaths were caused by such events. Furthermore, even though these bones were found in close association with large charcoal fragments, the bones lack evidence of direct exposure to fire, except for the extreme upper ends. Radiocarbon ages of the surrounding charcoal (~1650 BCE) are contemporary with those elsewhere in the destruction event. We also searched and found human bone fragments in palace bulk sediments, ~15 m away from the skeletons on the ring road. We quantified bone abundance in the fraction using a >1.2 mm screen (#12 ASTM sieve). The destruction layer was found to contain ~19 bone fragments per kilogram, weighing 3.2 g/kg. The largest bone was ~2.1 cm long ×0.8 cm wide (average size of bones=0.6×0.2 cm). In nine other samples, three above the destruction layer and six below, no other bone fragments were observed. After excavating nearly 100 squares (0.36 ha or ~1% of the site), researchers have found ~10 partial human skeletons, out of an estimated city population of ~8000 people². However, dozens to hundreds of broken and disarticulated bone fragments have been found in each of the 100 squares but these were too small to be conclusively identified as human or animal." - Bunch et al. (2021:44-45) "A medical doctor (co-author T.W.) inspected the human bones and concluded that the injuries occurred perimortem, including damage to the eye socket of one skull. We propose that the individuals represented by the bones were violently torn apart by a powerful airburst/impact, leaving only a few hand and foot bones still articulated and unbroken. It would not be possible to duplicate these injuries and disperse the bones as found in this layer by warfare or by accidental falls from a great height, e.g., off the adjacent rampart. Although tornadoes (max winds of ~512 km/h or ~318 mph) can cause bone breakage, organ damage, and disarticulation (Supporting Information, Text S3), they are exceedingly rare in Jordan or Israel and typically of low intensity. In any event, no known tornado has been shown to burn bones and break them into small fragments. The most severe known injuries to human bodies result from the impact of airborne high-velocity objects, such as during explosions and tornadoes (Supporting Information, Text S3). In addition, the ground-hugging blast wave from an airburst/impact would be laden with high-velocity missiles, including sand, gravel, pulverized mudbrick, plaster fragments, potsherds, broken branches, and shattered timbers. At tornado-force wind velocities and extremely high ambient temperatures, these missiles would be capable of incinerating or stripping flesh and crushing bones. Current evidence suggests that the human mortality rate at Tell el-Hammam was very high, so that most likely none of the ~8000 inhabitants survived. Based on the distribution of human bones on the upper and lower tall, we propose that the force of a high-temperature, debris-laden, high-velocity blast wave from an airburst/impact incinerated and flayed their exposed flesh decapitated and dismembered some individuals shattered many bones into mostly cm-sized fragments scattered their bones across several meters buried the bones in the destruction layer, and charred or disintegrated any bones that were still exposed. In summary, although man-made explosives and atomic bombs can account for an extreme range of damage to humans, they can be ruled out because of the age of the site. In addition, warfare, accidents, and tornadoes can be eliminated because they are incapable of causing the observed severe skeletal damage at Tell el-Hammam. The circumstances and condition of the human bones and fragments suggest that at the moment of death, these individuals were going about normal activities inside the palace, on the upper ring road, and/or on the rampart above the road, where they were struck by a high-temperature thermal pulse, followed by a hyper-velocity blast wave from a catastrophic cosmic airburst. This event was most likely larger than the airburst at Tunguska, Siberia in 1908, where ~500 reindeer and several herders within the blast radius suffered severe burns and were killed, but suffered no disarticulation." - Bunch et al. (2021:46-47)
Collapsed Walls Sheared Walls Collapsed Roof Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Upper Tall - Field UA - Middle Bronze Palace Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Fig. S1 Fig. S1 Collapsed multi-storied palace. Photo showing jumbled remains of three stories of the palace; the fourth story is completely missing. #1 represents a circular clay MBA oven called a tabun. #2 is a broken potsherd. #3 represents broken and burned mudbricks from the upper walls. #4 represents sections of burned roofing and upper-story flooring material. #5 represents charred wood from upper stories. The ‘blow-over’ layer capped and sealed the destroyed palace, which lay undisturbed for ~600 years. One-meter scale stick shown with 10-cm markings. Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 15 Fig. 15 The directionality of mudbricks, potsherds, and grains 400-kg quern, at left, used for grinding grain, is tipped over with top towards NE. Image view spans~2.5 m. Area #1 shows broken pottery and meltglass piled against quern from SW to NE (arrow). Area #2 contains charcoal, charred grains, ash, and mudbrick fragments, but no potsherds, suggesting that the quern shielded the floor to the NE. The area at the top labeled ‘blow-over’ is evidence that strong winds sealed the deposit with windblown laminated material that includes pulverized mudbrick, charcoal, ash, and fragments of white plaster. The draping of the blowover indicates debris traveled from SW to NE. The scale stick is in 10-cm intervals Directional potsherds. Blue, red, and green asterisks (*) represent color-coded potsherds from three different pots. Arrows mark the motion of potsherds from SW to NE, spanning ~1 m. Area #1 represents the inverted bottom of the pot with its smaller fragments strewn to the left. Some pots contained charred grains also strewn in a SW-to-NE direction. Radiocarbon dates on charred grains confirm an age of ~1650 BCE (3600 cal BP) Click on image to open in a new tab Bunch et al. (2021) Fig. 16 Fig. 16 High-velocity effects Photo of an excavated section of the palace wall on upper tall. In the center are the lower courses of the mudbrick wall (#1a, between white dashed lines) and foundation (#1b). Yellow dashed line with arrow indicates wind direction of blow-over to NE. Also, note the lines of white fragments of broken plaster at two blue arrows (#4), where the curved wall top displays intense wind abrasion. At the right side of the image, #6 marks the limit of modern excavation. The sequence of wall destruction is illustrated in panels ‘b’ to ‘e’ below. An artistic depiction, re-creating the pre-destruction mudbrick wall and foundation highlighted in red (#1) Rubble in red (#2) was blown against the SW-facing side of the wall; material mainly consists of pulverized mudbricks and shattered potsherds Section of wall higher than several courses of mudbrick was demolished and blown to the NE to form the debris matrix (#3) High-velocity winds blew from SW to NE (arrows), severely abrading the top of the wall, and burying it in debris. Winds produced the laminated ‘blow-over’ (#4), containing small pulverized mudbricks, fragments of white wall plaster, and limestone spherules stripped from interior walls. Settling on top, the ‘dark layer’ (#5) is mostly composed of charcoal and ash from the city-wide fires, along with post-destruction fine particulates Click on image to open in a new tab Bunch et al. (2021) Fig. 7 Fig. 7 Destruction layer in the palace Photo of excavation in an exterior food preparation area of the palace. #1 marks MB II debris that was most likely deposited by post-fie erosion. #2 points to charcoal-rich ‘dark layer’ indicating a major fie in the palace. Contains fragments of plaster and limestone spherules. Blue arrows mark its top. #3 points to the cross-section of excavated clay floring Close-up photo of the same palace sampling sequence as in panel ‘a’ Photo of broken pots with carbonized grains embedded in MB II 1.5-m-thick debris matrix, mostly composed of pulverized mudbrick and plaster fragments and limestone spherules. Debris matrix is found in the space between all palace walls. Note charcoal inside the broken pot. Te end of a scale stick with 10-cm divisions is at upper left Charred palace roof timber surrounded by 1.5-m-thick charcoal-rich debris matrix of pulverized mudbrick. A scale stick shows 10-cm markings Click on image to open in a new tab Bunch et al. (2021) Fig. 2 Fig. 2 Catastrophic leveling of the palace at Tall al-Hammam Artist’s evidence-based reconstruction of the 4-to-5-story palace that was ~ 52 m long and 27 m wide before its destruction Artist’s evidence-based reconstruction of palace site on upper tall, along with modern excavation. “MB II” marks the top of 1650-BCE Middle Bronze rubble. Note that the fild around the excavation is essentially fat, unlike the view in panel ‘a’. Originally, parts of the 4-story palace were ~ 12 + m tall, but aferward, only a few courses of mudbricks remain on stone foundations, labeled as “wall remnants”. Part of the foundation of the massive wall around the palace is at the bottom. Debris from between sheared walls has been removed by excavation. A comparison of panel ‘a’ to panel ‘b’ shows that millions of mudbricks from the upper parts of the palace and other buildings are missing. Click on image to open in a new tab Bunch et al. (2021) Fig. 3 Fig. 3 Destruction of the multi-storied palace. Photo showing jumbled rubble of four-story Palace atop Floor 1. Remains of debris from upper stories are labeled as follows. #1 represents broken mudbricks and debris from shattered upper walls #2 and #3 are voids and layers formed when trapped textiles (rugs and tapestries) burned, leaving only fbrous ash and carbon ‘Blow-over’ (in blue) is composed of windblown, laminated deposits that sealed the ruined structure for ~ 3600 years, beginning at the time of destruction. #4 marks fragments of white limestone plaster (CaCO₃) mixed with carbonate spherules from the palace walls and ceiling. Scale stick has 10-cm markings. Click on image to open in a new tab Bunch et al. (2021) Fig. 22 Fig. 22 LBA and MBA destruction layers in Square UA.7GG on Upper Tall el-Hammam Click on image to open in a new tab Silvia (2015)	Description(s) "The upper tall at Tall el‑Hammam had massive ~4-m-thick city wall foundations supporting freestanding mudbrick ramparts, multi-story mudbrick buildings including a palace complex (Fig. 2a), and a monumental gateway. Today, almost no mudbricks remain on MB II stone foundations except for a dozen or so mudbrick courses surviving on the northeast side of the 33-m-high upper tall, where no MB II mudbrick superstructure stands more than 12–15 courses high. All walls are seemingly sheared off nearly level with the tops of the upper-city wall foundations, many of which have several surviving mudbrick courses. This includes the massive palace complex that once had walls ranging from 1.0 to 2.2 m in thickness and likely rising to ~11–15 m in height. ... The ~4–5-story-tall palace complex (~52 m × ~27 m), with massive superstructures made of sun-dried mudbricks (Fig. 2a), extended ~11–15 m above the top of the enclosing rampart. The palace excavations reveal that most of the first- floor walls and all of the upper stories of the MB II palace are missing, with no evidence of collapsed walls across the entire upper tall. There are almost no whole mudbricks visible anywhere, and instead, small fragments of bricks are randomly strewn around as infill within the churned- up, 1.5-m-thick destruction matrix. It appears that most bricks were pulverized and blown off the site to the northeast. (Figs. 2b, 3; Supporting Information, Fig. S1)." - Bunch et al. (2021:3-5)
Collapsed Walls Collapsed Roof Fire Abandonment	Upper Tall - Field UB Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Fig. 7.12 MB2 destruction layer on the Upper Tall, Field UB. Click on image to open in a new tab Collins et al. (2015)	Description(s) "Surface-melted potsherds were found about 15 m northeast of the palace complex in the destruction layer in Field UB (Fig. 10). These were associated with numerous unmelted potsherds within a sealed MB II context that is deeply buried in undisturbed sediment beneath~2.5 m of Iron Age walls, indicating that melted potsherds were not redeposited from younger strata. Their MB II age was determined by seriation (pottery styles) and radiocarbon dating of associated materials, typically charred seeds and grains. The potsherds were mixed within a heavily churned debris matrix, containing charcoal, ash, pulverized mudbrick, potsherds, roofing materials, and fragments of limestone building plaster." - Bunch et al. (2021:13)
Collapsed Walls Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Lower Tall Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Fig. 7.13 Terminal MBA destruction layer on the Lower Tall Click on image to open in a new tab Collins et al. (2015)	Description(s) "On the lower tall, these general characteristics [of Upper Tall Field UA - MB Palace] also apply. However, the MB II structures, particularly in the south, southwest, and west sectors of the lower city, seem to have suffered greater damage. For example, virtually no mudbricks survive on the stone foundations of lower-city domestic structures, even on the massive stone foundations of the 4–5-m-thick MB II city wall. Additionally, some of the large finishing stones of the city wall and associated pillar-bases of a monumental gateway show signs of heat fracturing. There are several courses of mudbricks surviving on the external towers flanking the MB II monumental gateway, but only to the height of the city wall stone foundations. The remains of the MB II stratum on the lower/outer city are largely exposed at the surface, with little to no evidence of erosional mudbrick detritus across the entire lower tall, similar to what is found on the upper tall. A heavy concentration of salt-laden ash makes up most of the shallow soil that covers the lower tall. More than 98% of the area of the lower tall was never built upon again during the 3600 years after the MB II terminal destruction. Although few-to-no MB II mudbrick courses remain on the lower tall, up to a dozen mudbrick courses remain on their stone foundations on the northeastern sector behind the high-rising upper-city defensive ramparts. This strongly suggests that whatever destroyed Tall el‑Hammam exhibited greater intensity across the southwest-facing sector. This also applies to the upper tall where excavated structures extend only to the height of the rampart and remaining upper-city wall foundations. Inside the depression created by the massive, surrounding defenses, all the MB II walls from 0.5 to more than 2 m in thickness are sheared off at half the height (~1.5 m) of the first story. Excavations across the entire upper and lower talls are consistent in showing the most damage on the southwest exposure of the lower city." - Bunch et al. (2021:3-5) "During Season 6¹³⁹, excavations were conducted in two 6-by-6-m squares along the ring road of the lower tall. Both squares revealed a significant abundance of disarticulated and fragmented human skeletal remains in the MB II destruction layer¹³⁹ (Fig. 44c). In one square, three partially intact skeletons were found. All bones observed were embedded in a loose debris matrix composed of pulverized mudbrick, ash, and charcoal (Fig. 44c). There are no indications of intentional burial, scavenging, accidental death, violence, or battle damage. Two osteologists examined the bones of two adults and one child¹³⁹. Disarticulation of the skeletons was generally severe, and for the adult skeletons, only leg bones were preserved. For one skeleton, ~10 cm of the ends of both femurs showed evidence of charring. The remaining skeleton was represented by many fragmented bones found in the surrounding matrix. Metatarsal bones were abnormally hyper-extended (i.e., joints were over-stretched) and the proximal phalanges were hyper-flexed at almost 90 degrees to the metatarsals. The right knee joint of one skeleton also was hyper-extended¹³⁹. In a nearby child’s skeleton, the legs were hyper-flexed backward and the knee joints were disarticulated. Another skeleton was found buried in a crouching position with the hands raised to the face, a posture commonly adopted for protecting the head, as occurred during the volcanic eruption at Pompeii¹⁴⁰. Bones were also found in another square, ~6 m south of the square containing the skeletons. This square contained ~100 bones/kg with average length of 5.0 mm (range 0.5 mm–4.7 cm) and average width of 1.0 mm (range 0.5–5.0 mm). The largest was a small rib bone (4 by 47 mm), either from a human infant or a small mammal. The bone fragments weighed ~6.0 g/kg. We also observed a 3.5-mm-long charred bone that had been splashed with meltglass (Fig. 45). In one case molten sediment had partially melted and mixed with the bone, flowed, and cooled in place. Previous experiments by Moore et al.¹⁷ suggest that such melting occurs at ≥1500 °C. These bones also were associated with geochemical anomalies. The rib bone is visibly salt-encrusted, measured by SEM–EDS at ~46 wt.% NaCl, and the NaCl content of the attached sediment was very high at ~54 wt.% (Fig. 46a). Anomalously high concentrations of salt were found only associated with the bones and sediment in the destruction layer at 1650 BCE, and not in strata above or below, indicating an unusual influx of salt at that time. The rib bone also exhibits several nuggets of silver and tin oxide (SnO2) (Fig. 46b) with morphologies suggesting that they splashed onto the bone and sediment while molten. Ag melts at ≥961 °C and SnO2 at ≥1630 °C, although elemental Sn melts at ~232 °C. The tin and silver nuggets are also similar to those observed in the surface of melted mudbricks in the palace that were found fused to meltglass in the temple complex (Fig. 46c) and observed splashed across loose sediment (Fig. 46d)." - Bunch et al. (2021:45-46) "A medical doctor (co-author T.W.) inspected the human bones and concluded that the injuries occurred perimortem, including damage to the eye socket of one skull. We propose that the individuals represented by the bones were violently torn apart by a powerful airburst/impact, leaving only a few hand and foot bones still articulated and unbroken. It would not be possible to duplicate these injuries and disperse the bones as found in this layer by warfare or by accidental falls from a great height, e.g., off the adjacent rampart. Although tornadoes (max winds of ~512 km/h or ~318 mph) can cause bone breakage, organ damage, and disarticulation (Supporting Information, Text S3), they are exceedingly rare in Jordan or Israel and typically of low intensity. In any event, no known tornado has been shown to burn bones and break them into small fragments. The most severe known injuries to human bodies result from the impact of airborne high-velocity objects, such as during explosions and tornadoes (Supporting Information, Text S3). In addition, the ground-hugging blast wave from an airburst/impact would be laden with high-velocity missiles, including sand, gravel, pulverized mudbrick, plaster fragments, potsherds, broken branches, and shattered timbers. At tornado-force wind velocities and extremely high ambient temperatures, these missiles would be capable of incinerating or stripping flesh and crushing bones. Current evidence suggests that the human mortality rate at Tell el-Hammam was very high, so that most likely none of the ~8000 inhabitants survived. Based on the distribution of human bones on the upper and lower tall, we propose that the force of a high-temperature, debris-laden, high-velocity blast wave from an airburst/impact incinerated and flayed their exposed flesh decapitated and dismembered some individuals shattered many bones into mostly cm-sized fragments scattered their bones across several meters buried the bones in the destruction layer, and charred or disintegrated any bones that were still exposed. In summary, although man-made explosives and atomic bombs can account for an extreme range of damage to humans, they can be ruled out because of the age of the site. In addition, warfare, accidents, and tornadoes can be eliminated because they are incapable of causing the observed severe skeletal damage at Tell el-Hammam. The circumstances and condition of the human bones and fragments suggest that at the moment of death, these individuals were going about normal activities inside the palace, on the upper ring road, and/or on the rampart above the road, where they were struck by a high-temperature thermal pulse, followed by a hyper-velocity blast wave from a catastrophic cosmic airburst. This event was most likely larger than the airburst at Tunguska, Siberia in 1908, where ~500 reindeer and several herders within the blast radius suffered severe burns and were killed, but suffered no disarticulation." - Bunch et al. (2021:46-47)

Archaeoseismic Intensity Estimates

City Wall Earthquake 1 - Early Bronze II/Early Bronze III Transition - ca. 2700 BCE

Earthquake Archeological

Earthquake Archeological Effects Chart

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Rodríguez-Pascua et al (2013)

Effects from Rodríguez-Pascua et al (2013: 221-224)

Effect	Location	Image(s)	Description(s)	Intensity
Collapsed Walls	Fortification Walls Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015) Fig. 5.10 EB2-3 wall, gate, and street Click on image to open in a new tab Collins et al. (2015) Fig. 5.11 Isometric drawing of EB2-3 gate Click on image to open in a new tab Collins et al. (2015) Fig. 5.12 Reconstruction drawing of EB2-3 gateway Click on image to open in a new tab Collins et al. (2015)	Fig. 5.8 Fig. 5.8 Earthquake activity of EB2 and EB3 rebuild of city wall at Tall al-Hammam Click on image to open in a new tab Collins et al. (2015) Fig. 5.9 Fig. 5.9 One of Tall al-Hammam’s EB2-3 gates Click on image to open in a new tab Collins et al. (2015)	"As it happened, Tall al-Hammam’s initial city wall (EB2) enclosed at least 25 hectares which was, in turn, surrounded by agricultural settlements in close proximity. But that wall was severely damaged— probably by an earthquake—during the transition from EB2 to EB3, ca. 2700 BCE. Excavated sections of the EBA city wall reveal that the EB2 phase had only one or two course-lines of medium to large boulders running parallel to the direction of the wall at the base of the inner and outer faces. Between the outer and inner lines of boulders the 6m-thick EB2 wall consisted of mudbricks only—thus its structural vulnerability. The subsequent EB3 version of the city wall was significantly more substantial, with the installation of an all-stone foundation of small-to-medium boulders, five to six courses laid to the full 6m width." - Collins et al. (2015:xxvii) "There was, however, a disruptive event that seems to have required residents to rebuild most of the architecture across the site at about the transition from EB2 to EB3, ca. 2700 BCE (Collins et al 2011, 2009). The EB2 to EB3 architectural interface is easily seen in the construction history of Hammam’s massive city wall—from 5.2m to 6m thick—enclosing an area in excess of 25ha (more than 60 acres). At some point toward the end of EB2 or beginning of EB3, a significant earthquake occurred that (seemingly) caused extensive damage over most of the city. (See Figure 5.8.) Evidence of this disruption is clearly visible as post-quake adjustments to the city wall foundation. The original EB2 foundation consisted of one to two rows of large stones set on bedrock along the inner and outer faces, with mudbricks between to the level of the stones. While this stone and mudbrick foundation required less effort than an all-stone approach, it turned out not to be a very good idea. The earthquake did so much damage that virtually the entire city wall had to be rebuilt. The EB2 wall was deconstructed down to what remained stable—which was not much. However, the EB3 builders determined that a few sections of the EB2 foundation remained stable enough to be incorporated into the new construction. Some of the EB2 stone and mudbrick foundation was purposefully left in place, and a massive, all-stone foundation—6m thick and six courses high—was installed. But curiously, in a few places, one or two courses of EB2 mudbricks are visible on the outer face underneath the EB3 all-stone foundation. Evidence of an EB2 direct-entry gateway is still visible in Field LA (Collins et al 2011)." - Collins et al. (2015:58-59) "Following the ca. 2700 BCE earthquake damage at Tall al-Hammam—similar to the devastation at Khirbet al-Batrawy at about the same time (Nigro 2008)—its city wall was widened slightly to about 6m in order to support a taller mudbrick superstructure built upon a foundation consisting of six courses of medium-to-large fieldstones. Partial remains of the mudbrick city wall—up to a dozen courses in places—remain intact. The stone foundation is preserved in its entirety over most of the length of the southern defenses (due to its integration into the later, and much larger, MBA fortifications) (Collins et al 2011, 2009)." - Collins et al. (2015:71-73)	VIII+
Collapsed Walls Fire	Residential Areas in Field LA in the Lower Tall Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015) Fig. 7.4 Tall al-Hammam-domestic architecture on the Lower Tall. Click on image to open in a new tab Collins et al. (2015) Fig. 7.6 Hammam’s Lower Tall MBA fortifications(in yellow). Click on image to open in a new tab Collins et al. (2015)	Fig. 2.5 Panoramic View of the Tall al-Hammam Excavations, LA Trench (Field LA). Click on image to open in a new tab Collins et al. (2015) Fig. 2.8 Horizontal Method at Tall al-Hammam, Field LA Click on image to open in a new tab Collins et al. (2015)	"A portion of the EB3 domestic area has been excavated directly inside the city wall near the gateway (Field LA). Apparent in all structures are the tightly knit phases of architectural evolution from EB2 and EB3, ultimately into the IBA and MBA, following the same footprints and wall lines, period to period, which is a clear indication of unbroken occupation. Ash, sometimes in remarkable quantities, is consistent throughout the EB2–3 domestic area (Field LA), further demonstrating the earthquake event that led to the houses being rebuilt." - Collins et al. (2015:71-73)	VIII+ ?

This evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224.

City Wall Earthquake 2 - Intermediate Bronze II/Middle Bronze I Transition - 2000-1950 BCE

Earthquake Archeological

Earthquake Archeological Effects Chart

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Rodríguez-Pascua et al (2013)

Effects from Rodríguez-Pascua et al (2013: 221-224)

Effect	Location	Image(s)	Description(s)	Intensity
Collapsed Walls	Fortification Walls Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)		"The IBA fortifications were still in use at Tall al-Hammam when a major earthquake devastated the city between 2000 and 1950 BCE, probably damaging the perimeter defenses beyond repair. But no matter—it seems that the city ‘fathers’ had something else in mind all along, and this was the perfect ‘excuse’ to put their plans into motion. What they envisioned was a new style of fortification system that rose to the challenges presented by rapidly evolving methods of siege warfare—siege towers, mobile battering rams, and sapper battalions skilled in the art of breaching city walls (Burke 2008; McAllister 2008). From what source(s) their system designs originated is unclear, but the same general type of ‘ramparted’ fortifications began to be built across both the southern and northern Levant around the beginning of the Middle Bronze Age (MB1), ca. 2000–1950 BCE." - Collins et al. (2015:xxvii)	VIII+

This evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224.

Fiery Destruction - Middle Bronze II - ca. 1650 BCE

Earthquake Archeological

Earthquake Archeological Effects Chart

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Rodríguez-Pascua et al (2013)

Effects from Rodríguez-Pascua et al (2013: 221-224)

Effect	Location	Image(s)	Description(s)	Intensity
Collapsed Walls Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Site-Wide Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. 4a Map of the city (white dashing line) showing sampling locations, spanning ~1100 m Source of base image: “Tall el-Hammam”. 31° 50.483 N, 35° 40.029 E. Google Earth; CNES/ Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Click on image to open in a new tab Bunch et al. (2021) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Human bone (HB) scatter in the ashy matrix of Hammam’s MB2 destruction Click on image to open in a new tab Collins & Scott (2016) Fig. 44 Human bones in the destruction layer Photo of a disarticulated skull found near the palace on the ring road around the upper tall. The right eye socket has been crushed (orange arrow). Skull is embedded in pulverized mudbrick containing numerous charcoal fragments (yellow circles) and is stained with ash commonly found in the destruction layer (blue arrow). Te orange tint of the skull suggests it was exposed to temperatures > 200 °C141 Rear view of the same skull in panel ‘a’ (blue arrow) near the second skull (purple arrow) and numerous disarticulated, fragmented human bones (orange arrows). Charcoal fragments at yellow circles Lower torso from the ring road of lower tall (orange arrows), and other disarticulated bones. Bones show evidence of being burned (red arrows); the rest of the skeleton is dismembered and disarticulated. Hyper-fleed toes (purple arrow) are consistent with either perimortem or postmortem exposure to high temperatures Click on image to open in a new tab Bunch et al. (2021) Fig. 17 The directionality of debris across the entire Tall el-Hammam site. Color-coded arrows indicate the type and direction of six types of debris. Red dashed arrow and colored arrows mark the movement from SW to NE across excavations that span an area of ~ 58,000 m2 (~ 480 m long by up to ~ 240 m wide). Created by the authors using Adobe Photoshop CC2014 (adobe.com/products/photoshop.html). Click on image to open in a new tab Bunch et al. (2021)	Description(s) "while the majority of sites in Cisjordan and Transjordan either limped or thrived into the Late Bronze Age, MBA civilization in the S Jordan Valley, anchored by Tall el-Hammam, never saw the dawn of LB1. From that moment—toward the end of MB2—occupation in this southernmost `circle' of the Jordan Valley ceased for the next 700 years. Focused research into the phenomenon that caused this devastation is ongoing. However, it is interesting to note that an analogous event, a fiery air-blast of cosmic origin, is now suggested to have brought about the demise of Tell Leilan, Tell Hjeira, and Tell Brak in Mesopotamia ca. 4200 BCE (Courty 2008, 2001, 1998; Weiss et al 1998)" - Collins et al. (2015:175) "The destruction of Bronze Age Tall al-Hammam, toward the end of MB2, was violent. On both the Upper and Lower Talls, a 1–1.5 m layer of ash, strewn with broken pottery, mudbricks, and a grisly repertoire of charred remains, is clearly visible in all excavated areas. (See Figure 7.12.) In adjacent agricultural fields, one can easily see that the soil composition is dominated by prodigious quantities of grey ash, in contrast to the reddish-brown (Munsell: 7.5yr) color of the natural soil. Many of the foundation stones of the MBA fortifications are burnt and heat-fractured. Whatever the origin and nature of this conflagration, it was terminal. Both Tall al-Hammam and the adjacent S Jordan Valley remained unoccupied until IA2, about 700 years later. (See Figure 7.13.)" - Collins et al. (2015:181) "All Tell el-Hammam sampling profiles investigated contain an MB II burn layer that is highly complex and variable across the tall but is generally composed of three parts. The first part is the deepest one and is mainly pulverized mudbrick, mixed with larger melted and unmelted mudbrick fragments, melted and unmelted roofing clay, ash, charcoal, charred seeds, unburnt wood, burned textiles, bones, plaster fragments, broken pottery, and melted pottery. We call this the “debris matrix.” It varies in thickness up to ~1.5 m and is only occasionally missing across the entire tall. The second part, immediately above the debris matrix, is composed of thin, windblown, fine-grained laminations, including fragments of broken plaster, limestone spherules, and charcoal, radiocarbon-dated to 1650 BCE. It is not present in all locations and instead is typically found on the NE sides of SW-facing wall remnants at the top of the debris matrix. This extraordinary stratum is termed the “blow-over layer.” Nothing similar has been identified in any older or younger deposits, beginning in the Early Bronze Age and extending through the Iron Age. The third part is a charcoal-and-ash-rich stratum that we call the “dark layer,” which is found everywhere across the tall and is typically only a few centimeters thick or less. However, on the outer, southwest-facing side of the large city gate, it is ~1 m thick. Sometimes the dark layer is present on top of the blow-over layer, but other times it is the only layer found, usually resting on top of an existing interior building floor. Its depth of burial varies considerably from being near the surface on parts of the lower tall to being buried 1–4 m across most of the upper tall. The debris matrix, the blow-over, and the dark layer collectively comprise the interval of interest called the “destruction layer.”" - Bunch et al. (2021:6-8) "During 15 field seasons at Tell el-Hammam, there have been extensive excavations of ~100 squares (each ~6 × 6 m in size) spread across the upper and lower tall. On Tell el-Hammam occupational surfaces older and younger than the MB II destruction layer, whole and broken pottery were nearly always found with all fragments confined to a small area that was their “working space.” In contrast, the destruction layer exhibits a distinct orientation pattern marking the movement of objects across the MBA-age excavated floors. Out of about 2000 different vessels represented in the palace destruction matrix, most are fragmentary, and not a single one, smashed or otherwise, has been found in its “working” place on a floor or other surface. Instead, nearly all pottery vessels were broken and strewn in a narrow SW-to-NE orientation spanning up to 10 m. On the rare occasions when intact or nearly intact ceramic vessels were found, they were seldom found on the SW side of walls, but rather were protected on the NE side of walls, often tilted to the NE and embedded in the destruction matrix. For example, the excavators uncovered an MBA-age food preparation room in the palace with more than 150 separate pottery vessels (some shown in Fig. 15). Shattered MB II potsherds were strewn across the palace floors from SW to NE, nearly always located within the bottom ~20 cm of a churned-up debris matrix that ranged in thickness from 50 to 150 cm. Grains, such as barley, that had been stored in some of the pots were also distributed from SW to NE, interspersed among the trail of potsherds. In another notable example, a distinctively decorated pot was found in pieces spread narrowly across ~6 m, with the majority of its decorated fragments concentrated against the SW-facing wall of the room. Broken potsherds from at least 50 separate vessels of all sizes have been found on this surface, and all pieces were strewn in the SW-to-NE direction. Figure 15b shows three examples of shattered pots with potsherds strewn in narrow paths across >60 cm in a SW–NE orientation. Before being excavated, they were embedded in pulverized mudbrick from the destruction layer. This pattern of directionality was also observed for larger objects. Within the sealed, undisturbed MB II context of the palace, excavators uncovered a heavy saddle quern (weight: ~400 kg or 880 lb; dimensions: ~90 × 50 × 40 cm). Made of dense local stone and used for grinding grain, the quern was found toppled from its dirt pedestal and tipped on its side on the floor of a food preparation area (Fig. 15a). The geometric axis of the quern aligns with the SW–NE direction. Barley grains that had once been on top of the quern were found carbonized and strewn across the floor ~1 m to the NE between the overturned quern and the SW-facing wall, suggesting SW-to-NE movement (Fig. 15a). Radiocarbon dating of carbonized wood and grain from this floor confirms ~1650 BCE (~3600 ±50 cal BP) as the date for the destruction event. Discussion of directionality. An inferred sequence of events that produced the destruction layer (collectively the lower debris matrix, the blow-over above it, and the upper charcoal-rich dark layer) is shown in Fig. 16. Over a brief span of seconds, a high-velocity, debris-entrained shock wave arrived from the SW, demolished the mudbrick walls of the city, blew over the fallen walls, severely abrading (sand-blasting) the top surfaces, and deposited thin laminations of pulverized mudbrick, fragments of crushed building plaster, limestone spherules, ash, and charcoal, typically 20–30 cm thick (Fig. 16e). The wind demolished the portions of walls and ramparts that extended higher than several courses of mudbrick. Along interior walls, melted mudbrick, broken pottery, wall plaster, charred beams, and other interior debris were pushed against the SW-facing sides of walls that were typically 60–70 cm thick (Fig. 16c), filled the remaining space with pulverized debris (Fig. 16d), and blew the remainder off the tall to the NE. This sequence of fallen walls, capped by blow-over layers, appears to have occurred nearly instantaneously because there is no evidence of erosion or passage of time between the top dark layer, the blow-over layers, and the underlying debris matrix. Significantly, above the destruction layer, there is no evidence for extensive human occupation at Tell el-Hammam for ~600 years. Instead, gradual sediment erosion and redeposition buried the entire destruction layer. After that long hiatus, the city was only minimally rebuilt during the Iron Age and never returned to its former size and level of occupation. Evidence of directionality from SW to NE within buildings has been identified in ~100 excavated squares across the site. Directionality is indicated for up to six materials: melted pottery melted mudbricks blow-over detritus general building material seeds and grains potsherds Notably, all excavated squares, including the palace, temple, and ring road (Fig. 17), display evidence of SW–NE-trending blow-over materials, primarily composed of thinly laminated layers of pulverized mudbrick, ash, charcoal, and fragments of white plaster. Following the destruction event, archaeological evidence indicates that the city was only minimally rebuilt ~600 years later during the Iron Age. When that occurred, there is no apparent evidence that later inhabitants recycled surviving mudbricks for rebuilding the city. In any event, later structures are far too few to account for the massive number of missing mudbricks. Nearby cities were not rebuilt either, so no mudbricks from Tell el-Hammam could have been used for that purpose. Furthermore, the city foundations are sealed by pulverized mudbrick and charcoal that dates to ~1650 BCE throughout the city, indicating the destruction layer has remained undisturbed for >3600 years until modern times. In summary, the evidence is consistent with the hypothesis that the city’s mudbrick walls were pulverized by hypervelocity winds from a high-temperature event of cataclysmic proportions and the debris was blown off the tall to the NE." - Bunch et al. (2021:18-21)	VIII+ VIII+ ? ? ? ?
Collapsed Walls Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Upper Tall Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)		Description(s) "If the MB II destruction event at Tell el-Hammam was of sufficient magnitude and abruptness to be fatal for human inhabitants, as the evidence indicates, human remains should exist in the MB II layer. Indeed, human skeletal remains of sufficient size to be positively identified were found on the upper ring road that encircled the upper tall between the MB II defensive fortification wall and the outer wall of the MB II palace. Two human skulls were found about 20 cm apart (Fig. 44a, b), adjacent to a portion of a pelvis and a likely arm bone fragment. One skull was missing the mandible, and the right orbit was crushed about 50%. The second skull fragment consisted only of the upper dentition and lower half of the right orbit. Only two or three rib fragments were found and no other long bones were recovered. The forensic evidence suggests that the two bodies may have been decapitated, dismembered, and disarticulated. The record indicates that most of the bones had been shattered into small pieces and mixed into a matrix of pulverized mudbricks. Currently, it is not possible to determine if the small bones are from humans or small mammals, but their proximity to identifiable human bones makes it most likely that they are human. If so, only ~10% of the combined original bone mass of both humans is present as observable fragments within a 75-cm radius from the skulls. The remaining 90% of the two skeletons are missing and assumed to have been destroyed and/or located further away in the sediment matrix. These skeletons were found on the roadway around the upper tall, where the road was 3–4 m wide. The top of the nearby rampart was several meters wide. The remains were found at a depth of about four meters below the modern surface, well-sealed and undisturbed beneath archaeological sterile strata. The bodies had been rapidly entombed by pulverized mudbrick containing abundant ash and charcoal. No weapons were found associated with the skeletons or evidence of damage by weapons, and neither body showed any indication of exposure to scavengers. Although humans can be mortally affected by earthquakes, volcanism, and warfare, these bone characteristics, both individually and collectively, show no evidence that these human deaths were caused by such events. Furthermore, even though these bones were found in close association with large charcoal fragments, the bones lack evidence of direct exposure to fire, except for the extreme upper ends. Radiocarbon ages of the surrounding charcoal (~1650 BCE) are contemporary with those elsewhere in the destruction event. We also searched and found human bone fragments in palace bulk sediments, ~15 m away from the skeletons on the ring road. We quantified bone abundance in the fraction using a >1.2 mm screen (#12 ASTM sieve). The destruction layer was found to contain ~19 bone fragments per kilogram, weighing 3.2 g/kg. The largest bone was ~2.1 cm long ×0.8 cm wide (average size of bones=0.6×0.2 cm). In nine other samples, three above the destruction layer and six below, no other bone fragments were observed. After excavating nearly 100 squares (0.36 ha or ~1% of the site), researchers have found ~10 partial human skeletons, out of an estimated city population of ~8000 people². However, dozens to hundreds of broken and disarticulated bone fragments have been found in each of the 100 squares but these were too small to be conclusively identified as human or animal." - Bunch et al. (2021:44-45) "A medical doctor (co-author T.W.) inspected the human bones and concluded that the injuries occurred perimortem, including damage to the eye socket of one skull. We propose that the individuals represented by the bones were violently torn apart by a powerful airburst/impact, leaving only a few hand and foot bones still articulated and unbroken. It would not be possible to duplicate these injuries and disperse the bones as found in this layer by warfare or by accidental falls from a great height, e.g., off the adjacent rampart. Although tornadoes (max winds of ~512 km/h or ~318 mph) can cause bone breakage, organ damage, and disarticulation (Supporting Information, Text S3), they are exceedingly rare in Jordan or Israel and typically of low intensity. In any event, no known tornado has been shown to burn bones and break them into small fragments. The most severe known injuries to human bodies result from the impact of airborne high-velocity objects, such as during explosions and tornadoes (Supporting Information, Text S3). In addition, the ground-hugging blast wave from an airburst/impact would be laden with high-velocity missiles, including sand, gravel, pulverized mudbrick, plaster fragments, potsherds, broken branches, and shattered timbers. At tornado-force wind velocities and extremely high ambient temperatures, these missiles would be capable of incinerating or stripping flesh and crushing bones. Current evidence suggests that the human mortality rate at Tell el-Hammam was very high, so that most likely none of the ~8000 inhabitants survived. Based on the distribution of human bones on the upper and lower tall, we propose that the force of a high-temperature, debris-laden, high-velocity blast wave from an airburst/impact incinerated and flayed their exposed flesh decapitated and dismembered some individuals shattered many bones into mostly cm-sized fragments scattered their bones across several meters buried the bones in the destruction layer, and charred or disintegrated any bones that were still exposed. In summary, although man-made explosives and atomic bombs can account for an extreme range of damage to humans, they can be ruled out because of the age of the site. In addition, warfare, accidents, and tornadoes can be eliminated because they are incapable of causing the observed severe skeletal damage at Tell el-Hammam. The circumstances and condition of the human bones and fragments suggest that at the moment of death, these individuals were going about normal activities inside the palace, on the upper ring road, and/or on the rampart above the road, where they were struck by a high-temperature thermal pulse, followed by a hyper-velocity blast wave from a catastrophic cosmic airburst. This event was most likely larger than the airburst at Tunguska, Siberia in 1908, where ~500 reindeer and several herders within the blast radius suffered severe burns and were killed, but suffered no disarticulation." - Bunch et al. (2021:46-47)	VIII+ VIII+ ? ? ? ?
Collapsed Walls Sheared Walls (displaced walls) Collapsed Roof (displaced walls) Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Upper Tall - Field UA - Middle Bronze Palace Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Fig. S1 Fig. S1 Collapsed multi-storied palace. Photo showing jumbled remains of three stories of the palace; the fourth story is completely missing. #1 represents a circular clay MBA oven called a tabun. #2 is a broken potsherd. #3 represents broken and burned mudbricks from the upper walls. #4 represents sections of burned roofing and upper-story flooring material. #5 represents charred wood from upper stories. The ‘blow-over’ layer capped and sealed the destroyed palace, which lay undisturbed for ~600 years. One-meter scale stick shown with 10-cm markings. Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 15 Fig. 15 The directionality of mudbricks, potsherds, and grains 400-kg quern, at left, used for grinding grain, is tipped over with top towards NE. Image view spans~2.5 m. Area #1 shows broken pottery and meltglass piled against quern from SW to NE (arrow). Area #2 contains charcoal, charred grains, ash, and mudbrick fragments, but no potsherds, suggesting that the quern shielded the floor to the NE. The area at the top labeled ‘blow-over’ is evidence that strong winds sealed the deposit with windblown laminated material that includes pulverized mudbrick, charcoal, ash, and fragments of white plaster. The draping of the blowover indicates debris traveled from SW to NE. The scale stick is in 10-cm intervals Directional potsherds. Blue, red, and green asterisks (*) represent color-coded potsherds from three different pots. Arrows mark the motion of potsherds from SW to NE, spanning ~1 m. Area #1 represents the inverted bottom of the pot with its smaller fragments strewn to the left. Some pots contained charred grains also strewn in a SW-to-NE direction. Radiocarbon dates on charred grains confirm an age of ~1650 BCE (3600 cal BP) Click on image to open in a new tab Bunch et al. (2021) Fig. 16 Fig. 16 High-velocity effects Photo of an excavated section of the palace wall on upper tall. In the center are the lower courses of the mudbrick wall (#1a, between white dashed lines) and foundation (#1b). Yellow dashed line with arrow indicates wind direction of blow-over to NE. Also, note the lines of white fragments of broken plaster at two blue arrows (#4), where the curved wall top displays intense wind abrasion. At the right side of the image, #6 marks the limit of modern excavation. The sequence of wall destruction is illustrated in panels ‘b’ to ‘e’ below. An artistic depiction, re-creating the pre-destruction mudbrick wall and foundation highlighted in red (#1) Rubble in red (#2) was blown against the SW-facing side of the wall; material mainly consists of pulverized mudbricks and shattered potsherds Section of wall higher than several courses of mudbrick was demolished and blown to the NE to form the debris matrix (#3) High-velocity winds blew from SW to NE (arrows), severely abrading the top of the wall, and burying it in debris. Winds produced the laminated ‘blow-over’ (#4), containing small pulverized mudbricks, fragments of white wall plaster, and limestone spherules stripped from interior walls. Settling on top, the ‘dark layer’ (#5) is mostly composed of charcoal and ash from the city-wide fires, along with post-destruction fine particulates Click on image to open in a new tab Bunch et al. (2021) Fig. 7 Fig. 7 Destruction layer in the palace Photo of excavation in an exterior food preparation area of the palace. #1 marks MB II debris that was most likely deposited by post-fie erosion. #2 points to charcoal-rich ‘dark layer’ indicating a major fie in the palace. Contains fragments of plaster and limestone spherules. Blue arrows mark its top. #3 points to the cross-section of excavated clay floring Close-up photo of the same palace sampling sequence as in panel ‘a’ Photo of broken pots with carbonized grains embedded in MB II 1.5-m-thick debris matrix, mostly composed of pulverized mudbrick and plaster fragments and limestone spherules. Debris matrix is found in the space between all palace walls. Note charcoal inside the broken pot. Te end of a scale stick with 10-cm divisions is at upper left Charred palace roof timber surrounded by 1.5-m-thick charcoal-rich debris matrix of pulverized mudbrick. A scale stick shows 10-cm markings Click on image to open in a new tab Bunch et al. (2021) Fig. 2 Fig. 2 Catastrophic leveling of the palace at Tall al-Hammam Artist’s evidence-based reconstruction of the 4-to-5-story palace that was ~ 52 m long and 27 m wide before its destruction Artist’s evidence-based reconstruction of palace site on upper tall, along with modern excavation. “MB II” marks the top of 1650-BCE Middle Bronze rubble. Note that the fild around the excavation is essentially fat, unlike the view in panel ‘a’. Originally, parts of the 4-story palace were ~ 12 + m tall, but aferward, only a few courses of mudbricks remain on stone foundations, labeled as “wall remnants”. Part of the foundation of the massive wall around the palace is at the bottom. Debris from between sheared walls has been removed by excavation. A comparison of panel ‘a’ to panel ‘b’ shows that millions of mudbricks from the upper parts of the palace and other buildings are missing. Click on image to open in a new tab Bunch et al. (2021) Fig. 3 Fig. 3 Destruction of the multi-storied palace. Photo showing jumbled rubble of four-story Palace atop Floor 1. Remains of debris from upper stories are labeled as follows. #1 represents broken mudbricks and debris from shattered upper walls #2 and #3 are voids and layers formed when trapped textiles (rugs and tapestries) burned, leaving only fbrous ash and carbon ‘Blow-over’ (in blue) is composed of windblown, laminated deposits that sealed the ruined structure for ~ 3600 years, beginning at the time of destruction. #4 marks fragments of white limestone plaster (CaCO₃) mixed with carbonate spherules from the palace walls and ceiling. Scale stick has 10-cm markings. Click on image to open in a new tab Bunch et al. (2021) Fig. 22 Fig. 22 LBA and MBA destruction layers in Square UA.7GG on Upper Tall el-Hammam Click on image to open in a new tab Silvia (2015)	Description(s) "The upper tall at Tall el‑Hammam had massive ~4-m-thick city wall foundations supporting freestanding mudbrick ramparts, multi-story mudbrick buildings including a palace complex (Fig. 2a), and a monumental gateway. Today, almost no mudbricks remain on MB II stone foundations except for a dozen or so mudbrick courses surviving on the northeast side of the 33-m-high upper tall, where no MB II mudbrick superstructure stands more than 12–15 courses high. All walls are seemingly sheared off nearly level with the tops of the upper-city wall foundations, many of which have several surviving mudbrick courses. This includes the massive palace complex that once had walls ranging from 1.0 to 2.2 m in thickness and likely rising to ~11–15 m in height. ... The ~4–5-story-tall palace complex (~52 m × ~27 m), with massive superstructures made of sun-dried mudbricks (Fig. 2a), extended ~11–15 m above the top of the enclosing rampart. The palace excavations reveal that most of the first- floor walls and all of the upper stories of the MB II palace are missing, with no evidence of collapsed walls across the entire upper tall. There are almost no whole mudbricks visible anywhere, and instead, small fragments of bricks are randomly strewn around as infill within the churned- up, 1.5-m-thick destruction matrix. It appears that most bricks were pulverized and blown off the site to the northeast. (Figs. 2b, 3; Supporting Information, Fig. S1)." - Bunch et al. (2021:3-5)	VIII+ VII+ VII+ VIII+ ? ? ? ?
Collapsed Walls Collapsed Roof (due to displaed walls) Fire Abandonment	Upper Tall - Field UB Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Fig. 7.12 MB2 destruction layer on the Upper Tall, Field UB. Click on image to open in a new tab Collins et al. (2015)	Description(s) "Surface-melted potsherds were found about 15 m northeast of the palace complex in the destruction layer in Field UB (Fig. 10). These were associated with numerous unmelted potsherds within a sealed MB II context that is deeply buried in undisturbed sediment beneath~2.5 m of Iron Age walls, indicating that melted potsherds were not redeposited from younger strata. Their MB II age was determined by seriation (pottery styles) and radiocarbon dating of associated materials, typically charred seeds and grains. The potsherds were mixed within a heavily churned debris matrix, containing charcoal, ash, pulverized mudbrick, potsherds, roofing materials, and fragments of limestone building plaster." - Bunch et al. (2021:13)	VIII+ VII+ ? ?
Collapsed Walls Debris (due to collapsed walls) Directionality of Debris Emplacement Fatalities Fire Abandonment	Lower Tall Fig. 5.2 Reconstruction of Tall al-Hammam in Early Bronze 2-3. Collins et al. (2015) Fig. S2 Tall el-Hammam showing main excavated areas. Relevant field areas in the main manuscript at arrows are Field LA = ring road near the main gate for the lower tall Field LS = temple complex on the lower tall Fields UA, UB, UC = palace complex on the upper tall The wadi site is not shown Source of base image: "Tall el-Hammam." 31° 50.483, N 35° 40.029 E. Google Earth; CNES/Airbus. Imagery date: 11/26/2019; accessed: 4/4/2021. Permissions: https://about.google/brand-resource-center/products-and-services/geo-guidelines/ Modified by the authors using Adobe Photoshop CC2014 (adobe.com/ products/ photoshop.html). Click on image to open in a new tab Bunch et al. (2021) Supplemental Fig. 7.2 Tall al-Hammam in the MBA Click on image to open in a new tab Collins et al. (2015)	Fig. 7.13 Terminal MBA destruction layer on the Lower Tall Click on image to open in a new tab Collins et al. (2015)	Description(s) "On the lower tall, these general characteristics [of Upper Tall Field UA - MB Palace] also apply. However, the MB II structures, particularly in the south, southwest, and west sectors of the lower city, seem to have suffered greater damage. For example, virtually no mudbricks survive on the stone foundations of lower-city domestic structures, even on the massive stone foundations of the 4–5-m-thick MB II city wall. Additionally, some of the large finishing stones of the city wall and associated pillar-bases of a monumental gateway show signs of heat fracturing. There are several courses of mudbricks surviving on the external towers flanking the MB II monumental gateway, but only to the height of the city wall stone foundations. The remains of the MB II stratum on the lower/outer city are largely exposed at the surface, with little to no evidence of erosional mudbrick detritus across the entire lower tall, similar to what is found on the upper tall. A heavy concentration of salt-laden ash makes up most of the shallow soil that covers the lower tall. More than 98% of the area of the lower tall was never built upon again during the 3600 years after the MB II terminal destruction. Although few-to-no MB II mudbrick courses remain on the lower tall, up to a dozen mudbrick courses remain on their stone foundations on the northeastern sector behind the high-rising upper-city defensive ramparts. This strongly suggests that whatever destroyed Tall el‑Hammam exhibited greater intensity across the southwest-facing sector. This also applies to the upper tall where excavated structures extend only to the height of the rampart and remaining upper-city wall foundations. Inside the depression created by the massive, surrounding defenses, all the MB II walls from 0.5 to more than 2 m in thickness are sheared off at half the height (~1.5 m) of the first story. Excavations across the entire upper and lower talls are consistent in showing the most damage on the southwest exposure of the lower city." - Bunch et al. (2021:3-5) "During Season 6¹³⁹, excavations were conducted in two 6-by-6-m squares along the ring road of the lower tall. Both squares revealed a significant abundance of disarticulated and fragmented human skeletal remains in the MB II destruction layer¹³⁹ (Fig. 44c). In one square, three partially intact skeletons were found. All bones observed were embedded in a loose debris matrix composed of pulverized mudbrick, ash, and charcoal (Fig. 44c). There are no indications of intentional burial, scavenging, accidental death, violence, or battle damage. Two osteologists examined the bones of two adults and one child¹³⁹. Disarticulation of the skeletons was generally severe, and for the adult skeletons, only leg bones were preserved. For one skeleton, ~10 cm of the ends of both femurs showed evidence of charring. The remaining skeleton was represented by many fragmented bones found in the surrounding matrix. Metatarsal bones were abnormally hyper-extended (i.e., joints were over-stretched) and the proximal phalanges were hyper-flexed at almost 90 degrees to the metatarsals. The right knee joint of one skeleton also was hyper-extended¹³⁹. In a nearby child’s skeleton, the legs were hyper-flexed backward and the knee joints were disarticulated. Another skeleton was found buried in a crouching position with the hands raised to the face, a posture commonly adopted for protecting the head, as occurred during the volcanic eruption at Pompeii¹⁴⁰. Bones were also found in another square, ~6 m south of the square containing the skeletons. This square contained ~100 bones/kg with average length of 5.0 mm (range 0.5 mm–4.7 cm) and average width of 1.0 mm (range 0.5–5.0 mm). The largest was a small rib bone (4 by 47 mm), either from a human infant or a small mammal. The bone fragments weighed ~6.0 g/kg. We also observed a 3.5-mm-long charred bone that had been splashed with meltglass (Fig. 45). In one case molten sediment had partially melted and mixed with the bone, flowed, and cooled in place. Previous experiments by Moore et al.¹⁷ suggest that such melting occurs at ≥1500 °C. These bones also were associated with geochemical anomalies. The rib bone is visibly salt-encrusted, measured by SEM–EDS at ~46 wt.% NaCl, and the NaCl content of the attached sediment was very high at ~54 wt.% (Fig. 46a). Anomalously high concentrations of salt were found only associated with the bones and sediment in the destruction layer at 1650 BCE, and not in strata above or below, indicating an unusual influx of salt at that time. The rib bone also exhibits several nuggets of silver and tin oxide (SnO2) (Fig. 46b) with morphologies suggesting that they splashed onto the bone and sediment while molten. Ag melts at ≥961 °C and SnO2 at ≥1630 °C, although elemental Sn melts at ~232 °C. The tin and silver nuggets are also similar to those observed in the surface of melted mudbricks in the palace that were found fused to meltglass in the temple complex (Fig. 46c) and observed splashed across loose sediment (Fig. 46d)." - Bunch et al. (2021:45-46) "A medical doctor (co-author T.W.) inspected the human bones and concluded that the injuries occurred perimortem, including damage to the eye socket of one skull. We propose that the individuals represented by the bones were violently torn apart by a powerful airburst/impact, leaving only a few hand and foot bones still articulated and unbroken. It would not be possible to duplicate these injuries and disperse the bones as found in this layer by warfare or by accidental falls from a great height, e.g., off the adjacent rampart. Although tornadoes (max winds of ~512 km/h or ~318 mph) can cause bone breakage, organ damage, and disarticulation (Supporting Information, Text S3), they are exceedingly rare in Jordan or Israel and typically of low intensity. In any event, no known tornado has been shown to burn bones and break them into small fragments. The most severe known injuries to human bodies result from the impact of airborne high-velocity objects, such as during explosions and tornadoes (Supporting Information, Text S3). In addition, the ground-hugging blast wave from an airburst/impact would be laden with high-velocity missiles, including sand, gravel, pulverized mudbrick, plaster fragments, potsherds, broken branches, and shattered timbers. At tornado-force wind velocities and extremely high ambient temperatures, these missiles would be capable of incinerating or stripping flesh and crushing bones. Current evidence suggests that the human mortality rate at Tell el-Hammam was very high, so that most likely none of the ~8000 inhabitants survived. Based on the distribution of human bones on the upper and lower tall, we propose that the force of a high-temperature, debris-laden, high-velocity blast wave from an airburst/impact incinerated and flayed their exposed flesh decapitated and dismembered some individuals shattered many bones into mostly cm-sized fragments scattered their bones across several meters buried the bones in the destruction layer, and charred or disintegrated any bones that were still exposed. In summary, although man-made explosives and atomic bombs can account for an extreme range of damage to humans, they can be ruled out because of the age of the site. In addition, warfare, accidents, and tornadoes can be eliminated because they are incapable of causing the observed severe skeletal damage at Tell el-Hammam. The circumstances and condition of the human bones and fragments suggest that at the moment of death, these individuals were going about normal activities inside the palace, on the upper ring road, and/or on the rampart above the road, where they were struck by a high-temperature thermal pulse, followed by a hyper-velocity blast wave from a catastrophic cosmic airburst. This event was most likely larger than the airburst at Tunguska, Siberia in 1908, where ~500 reindeer and several herders within the blast radius suffered severe burns and were killed, but suffered no disarticulation." - Bunch et al. (2021:46-47)	VIII+ VIII+ ? ? ? ?

This evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224.

Notes and Further Reading

References

Articles and Books

Bunch, T. E., LeCompte, M. A., Adedeji, A. V., Wittke, J. H., Burleigh, T. D., Hermes, R. E., Mooney, C., Batchelor, D., Wolbach, W. S., Kathan, J., Kletetschka, G., Patterson, M. C. L., Swindel, E. C., Witwer, T., Howard, G. A., Mitra, S., Moore, C. R., Langworthy, K., Kennett, J. P., West, A., Silvia, P. J. (2021) A Tunguska sized airburst destroyed Tall el-Hammam, a Middle Bronze Age city in the Jordan Valley near the Dead Sea. Scientific Reports 11(1): 18632. – open access

Bunch et al. (2021) Supplementary Material – open access

Bunch, T. E., LeCompte, M. A., Adedeji, A. V., Wittke, J. H., Burleigh, T. D., Hermes, R. E., Mooney, C., Batchelor, D., Wolbach, W. S., Kathan, J., Kletetschka, G., Patterson, M. C. L., Swindel, E. C., Witwer, T., Howard, G. A., Mitra, S., Moore, C. R., Langworthy, K., Kennett, J. P., West, A., Silvia, P. J. (2022) Author correction: A Tunguska sized airburst destroyed Tall el-Hammam, a Middle Bronze Age city in the Jordan Valley near the Dead Sea. Scientific Reports 12(1): 3265. – open access

Bunch, T. E., LeCompte, M. A., Adedeji, A. V., Wittke, J. H., Burleigh, T. D., Hermes, R. E., Mooney, C., Batchelor, D., Wolbach, W. S., Kathan, J., Kletetschka, G., Patterson, M. C. L., Swindel, E. C., Witwer, T., Howard, G. A., Mitra, S., Moore, C. R., Langworthy, K., Kennett, J. P.,…Silvia, P. J. (2025). Retraction Note: A Tunguska sized airburst destroyed Tall el-Hammam a Middle Bronze Age city in the Jordan Valley near the Dead Sea. Scientific Reports, 15(1), 14291.

Collins, S., & Scott, L. C. (2016). Discovering the City of Sodom: The Fascinating, True Account of the Discovery of the Old Testament's Most Infamous City . Howard Books. - full access at academia.edu

Gilat A.L. and Vol A. (2015) Sodom and Gomorrah: Fires Created by Ignition of Combustible Gases by Earthquake-Impelled Thermobaric-Hydrothermal Explosions . J Geol Geophys 4:202 – open access

Jaret, S. J., Harris, R. S. (2022) No mineralogic or geochemical evidence of impact at Tall el-Hammam, a Middle Bronze Age city in the Jordan Valley near the Dead Sea. Scientific Reports 12(1): 5189. – open access

Rainey, A. F., Notley, R. S., & Karṭa. (2006). The Sacred Bridge: Carta's Atlas of the Biblical World. Carta.

Silvia, P. J. (2015) The Middle Bronze Age civilization‑ending destruction of the Middle Ghor. Ph.D. thesis, Trinity Southwest University

Sokol, E. V., Kozmenko, O. A., Kokh, S. N., & Vapnik, Y. (2012). Gas reservoirs in the Dead Sea area: evidence from chemistry of combustion metamorphic rocks in Nabi Musa fossil mud volcano . Russian Geology and Geophysics, 53(8), 745–762