Tyre started out as an island known as Sur which was eventually joined to the mainland. It has been occupied since the Bronze Age ( Marriner et al, 2005). Marriner et al (2005) provides the following background

Mother of Carthage and one of the greatest Phoenician city-states, Tyre’s golden age spanned between the 9th to 6th centuries BC, during which period it enjoyed an extensive zone of influence incorporating large areas of the Mediterranean basin. Although Tyre lost its hegemony after 572/3 BC, when it fell under Persian influence, the city continued to prosper through the Hellenistic, Roman and Byzantine periods as attest the many impressive archaeological remains today visible in the city.

William A. Ward in Meyers et al (1997) relates the following

Classical tradition states that King Hiram (969-936 BCE) joined the two reefs with landfill, enlarging the city to about 40 acres. In succeeding reigns, further enlargement allowed the creation of ports on the northern and southern sides of tire island. This island stronghold was joined to the mainland by Alexander the Great in 332 BCE, who constructed a causeway from the mainland in order to subjugate the city. By Roman times sand from sea currents quickly built up against this causeway, forming the present isthmus. Tyre was essentially an administrative and religious center dependent on food and water supplies from its "sister town," Ushu, on the coast, which stood amid rich and well-watered agricultural land. Ushu is known only from literary references as it lies beneath the modern city.

• Fig. 3 Macrofauna core TV
  Fig. 3
  
  Macrofauna core TV.
  
  Marriner et al (2005)
  from Marriner et al (2005)
• Fig. 4 Ostracoda core TV
  Fig. 4
  
  Ostracoda core TV.
  
  Marriner et al (2005)
  from Marriner et al (2005)
• Fig. 8 Grain size analyses
  Fig. 8
  
  Grain size analyses core TIX.
  
  Marriner et al (2005)
  core TIX from Marriner et al (2005)
• Fig. 9 Grain size analyses
  Fig. 9
  
  Grain size analyses core TI.
  
  Marriner et al (2005)
  core TI from Marriner et al (2005)
• Fig. 10 Macrofauna core
  Fig. 10
  
  Macrofauna core TIX.
  
  Marriner et al (2005)
  TIX from Marriner et al (2005)
• Fig. 11 Macrofauna core
  Fig. 11
  
  Macrofauna core TI.
  
  Marriner et al (2005)
  TI from Marriner et al (2005)
• Fig. 12 Ostracoda core TI
  Fig. 12
  
  Ostracoda core TI.
  
  Marriner et al (2005)
  from Marriner et al (2005)
• Fig. 13 Foraminifera core
  Fig. 13
  
  Foraminifera core TI.
  
  Marriner et al (2005)
  TI from Marriner et al (2005)
• Cross-correlation of stratigraphic
  Fig. 16
  
  Cross-correlation of stratigraphic units from cores in the northern harbour.
  
  Marriner et al (2005)
  units from cores in the northern harbour from Marriner et al (2005)

Marriner et al (2005) undertook a litho and biostratigraphical study of four core sequences from the landward edge of the current harbor. AMS radiocarbon dating was performed on dateable material found in the cores. They attributed missing 1st millennium BCE strata to dredging activity undertaken in the Roman and Byzantine periods.

Marriner et al (2005) undertook a litho and biostratigraphical study of four core sequences from the landward edge of the current harbor. AMS radiocarbon dating was performed on dateable material found in the cores. The cores appeared to capture harbor sediments and showed a clear break in sedimentaion at the end of the Byzantine era noting the following :

4.6. Unit A - Exposed beach environment (post-Byzantine)

The transition to unit A is dated to between the 6th to 10th centuries AD. The unit comprises a grey, shelly sand unit with textures of between: 3% to 31% for the gravels, 58% to 83% for the sands and 9% to 18% for the silts and clays.

Cerithium vulgatum and Pirenella conica dominatethe macrofauna suite, with numerous secondary species from diverse biocenoses (Ringicula auriculata, Nassarius pygmaeus, Gibberula miliaria ), consequence of an environmental opening. The increase in coastal ostracod taxa such as Urocythereis sp. and Aurila woodwardii, is to the detriment of the formerly abundant lagoonal taxa of unit B. This translates a re-exposure of the environment to the influence of the marine swell and currents. For the foraminifera, the dominant taxa are Ammonia convexa, Peneroplis planatus and Cellanthus craticulatum. The tests of many of these individuals have been broken by waveaction, confirming a rise in energy dynamics, due to the collapse of harbour maintenance. This is linked to the demise of Tyre as a Mediterranean commercial centre.

Core profiles were presented and tsunamites were not found in the parts of the cores dated to the 6th - 10th centuries CE but a loss of harbor maintenance (e.g. continuous dredging operations) was evident.

Morhange et al (2006:90) noted that

In Tyre, port opening may have been amplified by approx. 3 m collapse of the island after the 6th century AD (Marriner et al. 2005). Its northern Persian (?) mole is currently 2.5 m below present sea level (Descamps, pers. commun.), translating a subsidence of approx. 3-3.5 m. On the southern shore, drowned quarries at -2.5 m below MSL have also been discovered, and similar subsidence is translated in the city's coastal chronostratigraphy.