Hydroclimatic variability in the Levant during the early last glacial (∼ 117–75 ka) derived from micro-facies analyses of deep Dead Sea sediments

Abstract

Abstract. The new sediment record from the deep Dead Sea basin (ICDP core 5017-1) provides a unique archive for hydroclimatic variability in the Levant. Here, we present high-resolution sediment facies analysis and elemental composition by μXRF scanning of core 5017-1 to trace lake levels and responses of the regional hydroclimatology during the time interval from ca 117–75 ka, i.e. the transition between the last interglacial and the onset of the last glaciation. We distinguished six major micro-facies types and interpreted these and their alterations in the core in terms of relative lake level changes. The two end-member facies for highest and lowest lake levels are (a) up to several meters thick, greenish sediments of alternating aragonite and detrital marl laminae (aad) and (b) thick halite facies, respectively. Intermediate lake levels are characterised by detrital marls with varying amounts of aragonite, gypsum or halite, reflecting lower-amplitude, shorter-term variability. Two intervals of pronounced lake level drops occurred at ∼110–108 ± 5 and ∼93–87 ± 7 ka. They likely coincide with stadial conditions in the central Mediterranean (Melisey I and II pollen zones in Monticchio) and low global sea levels during MIS 5d and 5b. However, our data do not support the current hypothesis of an almost complete desiccation of the Dead Sea during the earlier of these lake level low stands based on a recovered gravel layer. Based on new petrographic analyses, we propose that, although it was a low stand, this well-sorted gravel layer may be a vestige of a thick turbidite that has been washed out during drilling rather than an in-situ beach deposit. Two intervals of higher lake stands at ∼108–93 ± 6 and ∼87–75 ± 7 ka correspond to interstadial conditions in the central Mediterranean, i.e. pollen zones St. Germain I and II in Monticchio, and GI 24 + 23 and 21 in Greenland, as well as to sapropels S4 and S3 in the Mediterranean Sea. These apparent correlations suggest a close link of the climate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern Hemisphere ice shields in the early last glacial period.

Reconstruction of MIS 5 climate in the central Levant using a stalagmite from Kanaan Cave, Lebanon

“…Moreover, Lake Samra records in the DSB are less out of phase with Levantine records further north than suggested for the last 20 kyr (Cheng et al, 2015). The DSB records, recently investigated with a higher chronological resolution (Neugebauer et al, 2015) than previous studies (Waldmann et al, 2009), show minor high levels during MIS 5c and 5a. These wet pulses indicate though wet periods but with smaller amplitude than the wet phase in the northern Levant.…”

“…These wet pulses indicate though wet periods but with smaller amplitude than the wet phase in the northern Levant. The climate picture of the DSB during the glacial inception is related probably to local factors influenced by the Judean rain shadow (Vaks et al, 2006(Vaks et al, , 2013 and, together with other continental records further south, invokes climatic variations driven by the monsoon system (Torfstein et al, 2015) and its boundary shifts (Parton et al, 2015;Bar-Mathews, 2014) or by the North Atlantic and Mediterranean climates (Neugebauer et al, 2015).…”

Seasonal variations of halite saturation in the Dead Sea

“…Hypersaline water bodies were common in the past, precipitating thick evaporitic halite deposits [Kozary et al, 1968;Ronov et al, 1980]. Halite deposits are commonly used as recorders for paleoclimate and paleohydrology [Neugebauer et al, 2014;Kiro et al, 2015;Neugebauer et al, 2015;Torfstein et al, 2015]. Fine lamination of halite deposits may be used for high temporal resolution recorders, provided that the processes governing the temporal and spatial variations of degree of saturation are well explored.…”

Late Holocene hydrology of Lake Maharlou, southwest Iran, inferred from high-resolution sedimentological and geochemical analyses

“…Fewer investigations have reconstructed lake paleohydrology in Iran with sedimentology and major element geochemistry, with the exception of Lake Urmia (Kelts and Shahrabi 1986) and the recent studies on Lake Neor (Sharifi et al 2015). These proxies may provide valuable highresolution data from which lake desiccation and fluvial activity can be reconstructed (Neugebauer et al 2016). In this study, we present new high-resolution sedimentological (dry bulk density, micro-facies analysis, X-ray diffraction) and major element (X-ray fluorescence) analyses of MAH-B, a 3.5-m-long sediment core, to investigate centennial-scale variations in the hydrology of Lake Maharlou for the last 3800 years.…”