Late-Pleistocene rise of the Sedom diapir on the backdrop of water-level fluctuations of Lake Lisan, Dead Sea basin

摘要

During the last glacial between ～70 and 15 kyr B.P., large parts of the Dead Sea rift were inundated by Lake Lisan. We use the established history of Lake Lisan water-level fluctuations as a tool for determining the rates and styles of the salt-tectonic uplift of the Sedom salt diapir. Our reconstruction is based on new, accurate MC-ICPMS U-Th ages of Lake Lisan deposits overlying the top of Mount Sedom, the surface expression of the Sedom diapir. These sediments range in age between 46.4 and 15.5 kyr B.P. Comparison of the present elevations of the studied Lisan sediments to the Lake Lisan level curve indicates that these sediments were uplifted to their present elevations due to the diapiric rise of Mount Sedom during the late Pleistocene. Lisan sediments older than 46.4 kyr B.P. were not found yet on Mount Sedom, suggesting that it was exposed prior to that time. We correlate the exposure phase of Mount Sedom with the lowest stand of Lake Lisan between ～48 and 43 kyr B.P., during which previously deposited sediments were eroded. The age of the top of the Lisan Formation on Mount Sedom is ～15.5 kyr B.P. and it has been uplifted by 75m since then.