SLIPPING UP? ESR DATING MOLLUSCS FROM MARINE TERRACES IN HATAY PROVINCE, TURKEY

Large earthquakes centered on the Dead Sea Fault Zone and its branches have destroyed Antioch (now Antakya) and devastated all Hatay Province several times during the historic period. Between Antakya and Samandağ on the Mediterranean coast, a NE-trending fault system, namely the Antakya-Samandağ Fault, connects Dead Sea Fault Zone to the Cyprean Arc. Although time-equivalent late Quaternary terraces across the fault system differ by ~ 15 m in elevation, late Cenozoic vertical displacements have uplifted the southeastern side by up to 150 m, relative to the northwestern side, producing a large fault scarp that parallels the Asi (Orontes) River. Tectonic uplift coupled with Quaternary sealevel fluctuations has produced several stacked marine terraces stranded above the current sealevel. Northwest of Çevlik and Mağaracık, at least four Quaternary terraces can be recognized, while near Meydan and Tekebaşı at least three terraces are clearly visible. Since ESR can date molluscs between 0.5 ka and 2 Ma, > 50 mollusc samples from > 15 locations on these marine terraces were independently dated by standard ESR. Ages were calculated using time-averaged and volumetrically averaged external dose rates, modelled by assuming typical water depths for the individual species and sedimentation rates estimated from geological criteria. The D420 deposit, 50 m Tekebaşı and 30 m Mağaracık terraces date to 76 to 115 ka in Marine Isotope Stage (OIS) 5, but some Mağaracık sites contain shells reworked from older, higher terraces. Although it formed earlier, probably by 45 ka, in OIS 3, the 8 m terrace at the Meydan Dump was buried by a landslide, probably some time after 17 ka, in late OIS 2. The oldest shells from the 170 m Tekebaşı terrace date to late OIS 11. Therefore, the tectonic uplift appears to have averaged ~ 1.1 and ~ 2.1 m/ky on the Mağaracık and Tekebaşı sides respectively.