High resolution environmental conditions of the last interglacial (MIS5e) in the Levant from Sr, C and O isotopes from a Jerusalem stalagmite

The southern Levant region at the fringe of the Saharan-Arabian deserts is particularly vulnerable to warming and desertification, therefore reconstruction of the hydroclimate conditions of this region during periods of past climate change provide important insight on what may occur in the future. Here we report on high temporal resolution Sr-87/Sr-86, delta C-13 and delta O-18 isotope data of a stalagmite from the Har Nof cave in Jerusalem, demonstrating major climate changes during the last interglacial MIS5e between similar to 131-116 ka. We combine also data from other caves in Israel and the ICDP Dead Sea deep drill core. The following palaeoenvironmental history is observed: At 131-127.5 ka, Jerusalem experienced moderate Mediterranean climate conditions. Desert dust accumulated above the cave, while salt deposition occurred in the Dead Sea. At 127.5-122 ka, across the MIS5e insolation peak and Sapropel S5 interval in the Mediterranean, highly negative speleothem delta O-18 indicate both Mediterranean and southern (tropical) derived rains. Surface cover diminished, and by 122 ka the Sr-87/Sr-86 and delta C-13 values indicate complete soil removal above the cave. Very high temperatures and intensive fires caused the removal of C-3 vegetation. The rainfall season shifted from winter to summer with tropical-sourced precipitation. At 122-120.5 ka, the Sr-87/Sr-86 ratios indicate contributions of sea salts. Extremely high speleothem delta C-13 values indicate no vegetation. At similar to 120.5-118 ka there was higher rainfall and lower temperatures, associated with reestablishment of vegetation, including savannah-like C-4 pioneer grasses that appeared on soil patches. At 118-116 ka, the sedimentation rate of Har Nof AF12 stalagmite is extremely low, indicating regional aridity, coinciding with massive salt deposition in the Dead Sea.

Automated summary

This study reconstructs the hydroclimate conditions of the southern Levant region and provides insights into future climate change. By analyzing stalagmite isotope data, the study reveals the climate changes in the region, including shifts in rainfall season, vegetation changes, and alterations in surface cover.