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. delta(18)O-delta(13)C 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 delta(18)O and delta(13)C values, which indicate deposition at temperatures of 12 degrees-16 degrees C, annual rainfall of 300-450 mm, and vegetation typical of a mixed C-3-C-4 type. From 17,000 to 10,000 yr B.P. (deglaciation in northern Europe) delta(18)O values dropped progressively, correlative with warming (2 degrees-3 degrees C) and a gradual increase in precipitation. A simultaneous decrease in delta(13)C gives a range expected for C-3-type vegetation. This period also shows significant delta(18)O and delta(13)C ''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 delta(18)O (corresponding to similar to 1000 mm rain) coupled with the highest delta(13)C (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. (C) 1997 University of Washington.