The last interglacial-glacial transition as recorded in sediments from the deep Dead Sea basin

The Dead Sea and its Pleistocene precursors act as amplifier lakes of climate change affecting the eastern Mediterranean region. The ~460 m long sediment core 5017-1, retrieved from the deepest part of the lake, ideally mirrors the climate variability of the last approximately 200-250 ka. In the current study, we focus on the upper part of the last interglacial Samra Formation (~135-70 ka BP; Waldmann et al., 2009) and the transition into the last glacial Lisan Formation (~70-14ka BP; e.g. Bartov et al., 2002). Overlying the ca 45 m thick main salt layered sequence deposited during the last interglacial, the analyzed ca 30 m thick interval in core 5017-1 is characterized by a lower ~20 m thick interval of predominant alternating aragonite and detrital marl (aad) with occasional intercalations of mass movement deposits, accumulated during temporary humid climatic conditions. The entire sequence is topped by an upper ~10 m thick interval of predominantly layered massive halite, reflecting a dryer climate. Micro-facies analysis on large-scale petrographic thin sections, XRF element scanning, grain size and magnetic susceptibility measurements have been carried out on this interval for detailed and high-resolution characterization of the sediments and interpretation in terms of depositional processes and their value as paleoclimate proxies. The finding of a most likely millennial-scale dry interval just before the beginning of the stratigraphically defined humid Lisan interval falls in agreement with a previously identified depositional hiatus and associated erosional unconformity in the shallower areas outcropping at the margins of the lake (Stein, 2001). However, the deposition of glacial-like aad sediments prior to this pronounced dry period stands in contrast to previous analyses on outcrops (Waldmann et al. 2009). Investigating sediments from the deep Dead Sea basin will hence allow understanding and better deciphering the depositional processes in relation with climatic change during the last interglacial-glacial transition on centennial and millennial time-scales. References: Bartov, Y., Stein, M., Enzel, Y., Agnon, A., and Reches, Z., 2002. Lake Levels and Sequence Stratigraphy of Lake Lisan, the Late Pleistocene Precursor of the Dead Sea: Quaternary Research, v. 57, p. 9-21. Stein, M., 2001. The sedimentary and geochemical record of Neogene-Quaternary water bodies in the Dead Sea Basin - inferences for the regional paleoclimatic history: Journal of Paleolimnology, v. 26, p. 271-282. Waldmann, N., Stein, M., Ariztegui, D., and Starinsky, A., 2009. Stratigraphy, depositional environments and level reconstruction of the last interglacial Lake Samra in the Dead Sea basin: Quaternary Research, v. 72, p. 1-15.