Late Quaternary Paleoclimate in the Eastern Mediterranean Region from Stable Isotope Analysis of Speleothems at Soreq Cave, Israel
The eastern Mediterranean continental paleoclimate during the past 25,000 years was determined by a high-resolution petrographic, stable isotopic, and age study of speleothems from Soreq Cave, Israel. δ 18O-δ 13C trends indicate that all speleothems older than 7000 yr formed under conditions that differ from those of today. The period from 25,000 to 17,000 yr B.P. was characterized by the highest δ 18O and δ 13C values, which indicate deposition at temperatures of 12°-16°C, annual rainfall of 300-450 mm, and vegetation typical of a mixed C 3-C 4type. From 17,000 to 10,000 yr B.P. (deglaciation in northern Europe) δ 18O values dropped progressively, correlative with warming (2°-3°C) and a gradual increase in precipitation. A simultaneous decrease in δ 13C gives a range expected for C 3-type vegetation. This period also shows significant δ 18O and δ 13C "spikes" which are correlatable with global events (e.g., Heinrich events and the Younger Dryas Stade). The speleothems that grew between 10,000 and 7000 yr B.P. have a unique petrography showing irregular thin laminae of various colors and much detritus. They have the lowest δ 18O (corresponding to ∼1000 mm rain) coupled with the highest δ 13C (caused by flooding events which stripped the soil cover). From 7000 to 1000 yr B.P. conditions became closer to those of today. This study demonstrates that global events which were recognized in Northern Europe and North Africa are also evident in the eastern Mediterranean and are reflected principally by large changes in the rainfall rate.