Discovery of high-level terraces of Last Glacial Lake Lisan (Dead Sea) and Eastern Mediterranean paleoclimatic implications

Abstract

Series of lake terraces were discovered on unconsolidated Cambrian siltstones in Al-Tayan Wadi along the eastern escarpment of the Dead Sea Rift (DSR). Altitudes were studied with DGPS and calcareous stromatolitic crusts were U/Th-dated and analysed for microstructure, mineral composition and Mg/Ca ratios. These terraces represent high stands of the glacial Lake Lisan, ~100 m higher than previously known.Terraces up to −19 m (with respect to present sea level) were discovered and dated to the early MIS 5a. At 79.2 ± 3.3 to 76.5 ± 5.6 ka, Lake Lisan stood at −56 to −66 m, indicating extraordinary humid conditions in the Levant during MIS 5a. Then the lake level dropped dramatically to −350 m at ~63.6 ± 0.56 ka, implying drier conditions during H6 and MIS 4. Just before 32 ka the lake recovered to > −137 m, suggesting a higher water input to Lake Lisan during MIS 3. At ~30 ka, during early MIS 2, the lake receded to −148 m associated with H3, further dropping to −152 m at ~27 ka BP and to −154 m at ~23 ka. Afterward, the lake receded sharply to −200 m at ~22.5 ka, consistent with dry conditions of H2. During LGM, Lake Lisan recovered to −160 m at ~19 ka, which implies a return to a positive water balance. Correspondence of Lisan regressions to MIS 4 and 2, and to Heinrich events of the North Atlantic 6, 5, 4, 3 and 2 indicates a dry climate of the Levant during these periods. Otherwise, the highest lake stands during MIS 5a and the sharp transgression of the lake during MIS 3 suggest wet climate of the Eastern Mediterranean during aforementioned periods.