We present the updated Holocene section of the Sofular Cave record from the southern Black Sea coast (northern Turkey); an area with considerably different present-day climate compared to that of the neighboring Eastern Mediterranean region. Stalagmite δ13C, growth rates and initial (234U/238U) ratios provide information about hydrological changes above the cave; and prove to be more useful than δ18O for deciphering Holocene climatic variations. Between ∼9.6 and 5.4 ka BP (despite a pause from ∼8.4 to 7.8 ka BP), the Sofular record indicates a remarkable increase in rainfall amount and intensity, in line with other paleoclimate studies in the Eastern Mediterranean. During that period, enhanced summertime insolation either produced much stronger storms in the following fall and winter through high sea surface temperatures, or it invoked a regional summer monsoon circulation and rainfall. We suggest that one or both of these climatic mechanisms led to a coupling of the Black Sea and the Mediterranean rainfall regimes at that time, which can explain the observed proxy signals. However, there are discrepancies among the Eastern Mediterranean records in terms of the timing of this wet period; implying that changes were probably not always occurring through the same mechanism. Nevertheless, the Sofular Cave record does provide hints and bring about new questions about the connection between regional and large scale climates, highlighting the need for a more extensive network of high quality paleoclimate records to better understand Holocene climate.
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The authors would like to thank Frank McDermott, A.M.Celal Şengör, Daniel Rufer, Naki Akçar, Sally Lowick and the two anonymous reviewers for their constructive comments on the manuscript. Marc Luetscher, Yaman Özakin and Martin Schneider are thanked for their support in the cave. We also thank Ahmet Sevinç for collecting, and Peter Nyfeler for his help with the preparation of rainwater samples. This work was supported by the Swiss National Science Foundation (grant PP002-110554/1 to D. F.), the U.S. National Science Foundation ( ESH 0502535 to R.L.E. and H.C.), the Gary Comer Science and Education Foundation ( CP41 to R.L.E.), and Istanbul Technical University .
- Black Sea
- Sea surface temperature