High Resolution Record of the Last Glacial history in Lake Lisan Sediments (Paleo-Dead Sea)

M Stein (Institute of Earth Sciences The Hebrew University, Givat Ram, Jerusalem ph. 2-6585548;e-mail:motis@vms.huji.ac.il) SL Goldstein (Lamont-Doherty Earth Observatory, Columbia University,Palisades, NY; Max-Planck Institut fur Chemie, Mainz); A Schramm (Max- Planck Institut fur Chemie, Mainz; GeoForschungsZentrum,Potsdam) (AGU Sponser: M Stein)

Lake Lisan, the late Pleistocene precursor of the Dead Sea, evolved through rapid fluctuations in its water level. The lake history reflects fluctuations between wetter and drier climatic conditions in the region. High lake stand conditions (wet periods) were accompanied by development of a layered configuration and precipitation of aragonite from the upper layer. This layer also acted as sulfate accumulator during the lake's high stands. The sulfate was removed, resulting in formation of gypsum beds, upon climatic- induced mixing between the upper and lower layers or even complete overturn of the lake during dry periods. During low lake stands thick clastic layers were accumulated in the shallow shoulders of the lake basin. Precise 230Th-234U ages obtained by TIMS on the aragonites allow us to compare the times of transitions in the lithology and lake configuration with the global climatic record. Lake Lisan existed between ~67 and 17 kyr (Stages 4,3 and 2 in the marine isotope record). We identified twenty two transitions in the lithology of the lake during this time interval (average of one transition in ~2.3 kyr). The low-stand clastic successions are well correlated with the warming events in the marine and ice core records while the lake was at high stands when the N. Atlantic-Arctic climate was cool. Finer structures in the mode of sedimentation appear throughout the section and can be correlated with shorter climatic cycles. Thus, the climate in the region is linked in finer details to the global climatic record.