Event G at Nahal Ze'elim site ZA-1 is a 50 cm thick liquefied sand layer from the uppermost part of the Ze'elim sequence. The seismite was found in the southern gully of Site ZA-1, some distance from where Events A-F were discovered. Its occurrence reflects a change in the depositional environment relative to the older part of the section. By this time the site was dominated by shoreline and nearshore conditions with abundant sandy sediment rather than the predominantly laminated lacustrine deposits that characterize much of the older sequence. As a result, earthquake deformation was expressed by sand liquefaction rather than by the formation of classic intraclast breccias or mixed layers.
Event G was identified in the southern gully of ZA-1. However, its stratigraphic position is defined relative to the northern gully section, where Events A–F were identified. In that reference section, Event G occurs ~600 cm above the base-level. It is situated below Event H. The two horizons are separated by several centimeters of lacustrine sediment composed of alternating aragonite and detrital laminae. This intervening lacustrine unit records a rise in Dead Sea level and is thought to correspond to the relatively high lake stand of the late nineteenth century. The preservation of a distinct liquefaction event in Event G indicates that strong ground shaking affected water-saturated sediments near the shoreline during the most recent phase of deposition represented in the ZA-1 section.
The chronology of Event G is constrained by a series of radiocarbon determinations from the uppermost part of the section. Samples from the sequence yielded, in stratigraphic order from bottom to top, lab ages of 260 ± 24 BP (KIA-8259) from the bottom of the sequence, 135 ± 31 BP (KIA-8261) from inside seismite G, 93 ± 36 (KIA-l1651) from the topmost lacustrine unit, and 279 ± 20 BP (KIA-8260) from seismite H. Calibrated Ages for these samples are 1520-1800 CE, 1670-1960 CE, 1670-1960 CE, and 1520-1670 CE respectively. The calibrated age ranges overlap substantially and the top sample is older than the deeper samples, reflecting potential reworking and the difficulties of dating very young sediments using radiocarbon methods. However, the stratigraphic position of Event G beneath a lacustrine unit associated with a late nineteenth-century CE rise in Dead Sea level, identified by Ken-Tor et al. (2001b) through reference to Klein (1961), indicates that the event predates that lake-level highstand. On the basis of this stratigraphic relationship, Ken-Tor et al. (2001a) and Ken-Tor et al. (2001b) correlated Event G with the 1834 CE Fellahin Revolt earthquake. Although, strictly speaking, the 2σ radiocarbon age range from sample KIA-8261 within Seismite G (1670–1960 CE) is broad enough to permit correlation with a number of historical earthquakes, the combined stratigraphic and sedimentological evidence favors the interpretation proposed by Ken-Tor et al. (2001a) and Ken-Tor et al. (2001b). In particular, the presence of a lacustrine unit separating Events G and H, interpreted as recording the late nineteenth-century highstand of the Dead Sea, and the occurrence of liquefied sands within water-saturated sediments associated with both events, support correlation of Event G with the 1834 CE Fellahin Revolt earthquake.
- Fig. 1c Oblique aerial photo of
SW Dead Sea showing Masada and Zeelim Plain from Agnon et al. (2006)
An oblique air photo looking southward at the southwestern part of the Dead Sea showing faults (solid lines) and locations of studied late Pleistocene sections M and PZ. MFZ—Masada Fault Zone. The photo was taken in 1940 when the lake level was 395 m below sea level. The current level is 420 m below sea level; additional area has emerged, including the Ze' elim fan outcrop.
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Agnon et al. (2006)- Nahal Ze'elim outcrop areas
in Google Earth
ZA-I is a guesstimate
click on image to explore this site on a new tab in Google Earth- Figure 2 Annotated Lithosection
of ZA-1 with interpreted ages noted from Ken-Tor et al. (2001a)
The lithology and chronology of a composite section exposed in Ze'elim Plain. The section is described from two outcrops exposed in different gullies 300 m apart. The correlation between the outcrops is based on the sedimentary sequence, laminae counting, and 14C dates. Ages presented in 14C years B.P. Deformed units (mixed layers and liquefied sands) are marked by capital letters.
slightly modified by JW - red dates as interpreted by JW added
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Ken-Tor et al. (2001a)- Figure 8 Age Model for ZA-1
from Agnon et al. (2006)
A modified age model for the Ze'elim section studied in outcrop (Ken-Tor et al., 2001a) and drill core (Migowski et al., 2004). A–H denote events discussed in the text. The present model was constrained by two rules:
(1) each event horizon (top of each intraclast breccia) matches a historical earthquake of notice.
(2) each continuous deposition segment shows a uniform deposition rate.
Two outcomes support the model. Two of the breccia layers match pairs of earthquakes (64–31 BCE; 1202–1210 CE) such that the earlier event horizon is within the breccia layer and the later event matches the top. With these assignments for the event horizons, the model gives a uniform sedimentation rate of 0.5 cm/yr during the three periods separated by hiatuses.
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Agnon et al. (2006)- Figure 3 Age Model for ZA-1
from Ken-Tor et al. (2001a)
Table 1
- Chronology of the deformed units (seismites) in the Ze'elim section. Solid dots represent 14C ages in years B.P. Error bars represent the ranges in the calibrated ages (2σ) of all samples in each stratigraphic horizon. Vertical thin lines represent historical earthquakes in the Dead Sea area, which were correlated to the deformed units in the Ze'elim section. Horizontal dashed arrows are drawn from the deformed units (listed in capital letters) to the correlative earthquakes.
- Sedimentation rates calculated for the lower part of the composite section. The longest calibrated range was used for calculating the minimum sedimentation rate, and the shortest range for calculating the maximum sedimentation rate. Two clear unconformities are evident. The upper one is dated to 1290-1420 A.D., and the lower one to 1030-1210 A.D. The lower unconformity is marked by a sharp decrease in the sedimentation rate. Vertical dashed lines represent earthquakes that lie within the sedimentological hiatuses. Sedimentation rate of the upper part of the section was not calculated because datable samples were insufficient.
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Ken-Tor et al. (2001a)- Figure 4c. Calibration Curve Event G
from Ken-Tor et al.(2001b)
The calibration curve from Stuiver et al. (1998) and the intersection of the 14C age of the samples collected from the seismites of the Ze'elim sequence. Thick dashed lines represent the 2σ error (68.2% confidence) and fine dashed lines the 1σ error (95.4% confidence). The uncertainty in the ages of samples collected from the seismites is reduced by overlapping calibrated ranges of stratigraphically lower samples and by correlating with historical earthquakes (in gray).
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Ken-Tor et al. (2001b)- Table 1 Radiocarbon Table
from Ken-Tor et al. (2001b)
AMS results of 14C dating. Calibrated dates according to Stuiver et al. (1998). The samples are listed by stratigraphic height, from top to bottom. Samples collected from seismite units are shown in bold.
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Ken-Tor et al. (2001b)- Table 1 Radiocarbon Table
from Ken-Tor et al. (2001a)
AMS Results of Radiocarbon Dating
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Ken-Tor et al. (2001a)- Table 2 Refined Radiocarbon Table
from Ken-Tor et al. (2001a)
The 14C Chronology of the Deformed Layers (Seismites)
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Ken-Tor et al. (2001a)- Figure 4e Calibrated Radiocarbon Ages
from Ken-Tor et al. (2001b)
Chronology of the seismite record
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Ken-Tor et al. (2001b)- Fig. 2 Sediment Core comparisons
and Age-Depth Models for Ein Gedi, En Feshka, and Nahal Zeelim from Migowski et al. (2004)
Lithology of the sediment cores and the established age-depth models of the different profiles. The Ze'elim coring profile is paralleled by the Ze'elim gully wall. The Ein Gedi chronology is based on 20 radiocarbon dates and on the varve-counted section (black line) in the upper part.
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Migowski et al. (2004)- Correlated Trench Logs used
to Produce Composite ZA-1 Litholog from Revital Bookman (née Ken-Tor)
The final lithosection of Bookman (née Ken-Tor) is a composite litholog derived from multiple sites located up to approximately 300 m apart. ZA-1 refers to the location from which a large portion of the composite lithosection was constructed. More landward gullies were used to capture the most recent earthquakes, including Events G (1834 CE) and H (1927 CE). Bookman referred to site ZA-1 as Site 2.
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Revital Bookman (née Ken-Tor)