FAULT FINDING: ESR DATING MOLLUSCS FROM MARINE TERRACES IN HATAY PROVINCE, TURKEY

In Hatay Province, Turkey, the strike-slip East Anatolian, Cyprean-Antakya, and Dead Sea Fault Zones separate the Anatolian, Arabian, African, and Cyprean Plates. Repeatedly, large earthquakes located on all three fault zones have destroyed Antioch (now Antakya) and Hatay. Near Samandağ, south of Antakya, three subparallel faults (= the Cyprean-Antakya Fault Zone) rim a hemi-graben where large vertical displacements have uplifted the southeastern side of the fault zone by > 150 m higher than the northwestern side during the Quaternary. Coupled with Quaternary cyclic sealevel fluctuations that reworked glacial sediment, coastal uplift has stranded several marine terraces high above the modern sealevel. Northwest of Çevlik and Mağaracık, at least four Quaternary terraces can be traced laterally for several kilometres, while near Meydan and Tekebaşı the lowest four terraces are visible, but less continuous laterally. Since ESR can date molluscs between 0.5 ka and 2 Ma, > 60 mollusc samples from 28 locations on these marine terraces were independently ESR dated to match the terraces across the graben in order to measure uplift rates. ESR ages were calculated using volumetrically averaged external dose rates. Time-averaged cosmic and sedimentary dose rates were modelled assuming typical water depths for individual species and sedimentation rates estimated from geological criteria. All the terraces have incorporated older reworked molluscs into their sediment, including molluscs > 1.8-2.0 Ma. Near Tekebaşı and Meydan, the 7-8 m terrace was constructed during 22-13 ± 1-2 ka in late MIS 2, while a slump that occurred on the terrace formed at 14 ± 1 ka. The 57 m terrace near Tekebaşı was constructed during late MIS 5 and 4 and correlates with the 30 m terrace near Mağaracık, suggesting that the Tekebaşı side of the graben is uplifting about twice as fast as the Mağaracık side. Also near Tekebaşı, the 170 m terrace correlated with OIS 9-11.