Dead Sea drawdown and monsoonal impacts in the Levant during the last interglacial

Abstract

Sediment cores recovered by the Dead Sea Deep Drilling Project (DSDDP) from the deepest basin of the hypersaline, terminal Dead Sea (lake floor at ∼725 m below mean sea level) reveal the detailed climate history of the lake's watershed during the last interglacial period (Marine Isotope Stage 5; MIS5). The results document both a more intense aridity during MIS5 than during the Holocene, and the moderating impacts derived from the intense MIS5e African Monsoon. Early MIS5e (∼133-128 ka) was dominated by hyperarid conditions in the Eastern Mediterranean-Levant, indicated by thick halite deposition triggered by a lake-level drop. Halite deposition was interrupted however, during the MIS5e peak (∼128-122 ka) by sequences of flood deposits, which are coeval with the timing of the intense precession-forced African monsoon that generated Mediterranean sapropel S5. A subsequent weakening of this humidity source triggered extreme aridity in the Dead Sea watershed and resulting in the biggest known lake level drawdown in its history, reflected by the deposition of thick salt layers, and a capping pebble layer corresponding to a hiatus at ∼116-110 ka. The DSDDP core provides the first evidence for a direct association of the African monsoon with mid subtropical latitude climate systems effecting the Dead Sea watershed. Combined with coeval deposition of Arabia and southern Negev speleothems, Arava travertines, and calcification of Red Sea corals, the evidence points to a climatically wet corridor that could have facilitated homo sapiens migration "out of Africa" during the MIS5e peak. The hyperaridity documented during MIS5e may provide an important analogue for future warming of arid regions of the Eastern Mediterranean-Levant.

Stable isotope compositions of speleothems from the last interglacial – Spatial patterns of climate fluctuations in Europe

“…10). At the same time the Dead Sea had elevated water levels (Torfstein et al, 2015), in agreement with the humid climate inferred for the eastern Mediterranean and increased Nile floods, leading to the formation of sapropel S5 (Grant et al, 2012). For the period of 128 to 123 ka Milner et al (2012) have suggested pronounced seasonality with increased summer aridity and winter precipitation on the basis of acicular aragonite formation (indicating enhanced evaporation) in an otherwise aquatic phase of the Tenaghi Philippon peatland (NE Greece).…”

Middle Palaeolithic find spots with Nubian cores from the Southern Negev and the Arava, Israel

“…The mean annual precipitation is 50 mm, usually falling in a few rainfall events per year. Past climatic records indicate that during glacial and interglacial periods between MIS 6 and MIS 4 the central Negev was mostly dry (Amit et al 2006;Vaks et al 2007), whereas short humid episodes (Negev Humid Periods, (2017) NHP), possibly resulting from a northern shift of the African Monsson system, occurred during interglacial times (Blome et al 2012;Kutzbach & Liu 1997;Larrasoaña et al 2013;Torfstein et al 2015;Vaks et al 2010). The last of the NHP (NHP-1) is dated to 142-109 ka and was synchronous with pluvial periods in the Sahara, the Egyptian Desert and the Arabian Peninsula (Osborne et al 2008;Osmond & Dabous 2004;Petit-Maire et al 2010;Rosenberg et al 2011;Yehudai et al 2017;Vaks et al 2006;.…”

Subsurface Seawater Intrusion, an Additional Factor Influencing the Limnological History of the Dead Sea Basin

“…A 40 m halite-dominant core was dated to 110-120 ka at a level of 235 m below the DS bottom ("blb"). Torfstein et al (2015a) related this to a sudden and rapid drawdown of the DS level. Katz and Starinsky (2015) commented by rejecting this interpretation, based on geochemical parameters.…”