EVIDENCE OF PAST ENVIRONMENTAL CONDITIONS DURING THE EVOLUTION OF AN ANCIENT SALINE LAKE IN THE AL-AZRAQ BASIN, JORDAN USING SEDIMENTOLOGY AND GEOCHEMISTRY

Cored sediments from the Al-Azraq basin, eastern Jordan record the Quaternary evolution of an ancient saline lake, ranging in age from 500–250 ka to the present (Davies, 2000; Khoury 2003; and Turner and Makhlouf, 2005). On the Jordan Plateau, the Al-Azraq is a low lying an endorheic basin draining an area across eastern Jordan, southern Syria and northern western Saudi Arabia of approximately 12,700 km². The basin is bounded to the west and east by silt dunes, and to the northwest by basaltic hills. Multiple proxies such as sedimentology, stable isotopes, ICPMS, magnetic susceptibility characterized the paleolake environments. The results of this investigation demonstrate significant changes in depositional processes and influxes of moisture. Sedimentation is characterized by periods of cyclic deposition, possibly varved, and high evaporation phases. Slumping and liquefaction features indicate possible episodes of tectonic activity. Fluctuations in magnetic susceptibility identify periods of basalt weathering from the northern basalt-rich portion of the drainage. Results indicate periods of moister and drier climate than the present.