LATE PLEISTOCENE - HOLOCENE PALEOENVIRONMENTAL CHANGES FROM THE ROMANIAN BLACK SEA SHELF INFERRED BY MICROFAUNAL AND ISOTOPE FLUCTUATIONS.

The transition of the Black Sea from an inland lake to a marine basin during the last glacial/deglacial episode is still generating discussion in the scientific community. Qualitative and quantitative study of the ostracod and foraminiferal assemblages coupled with isotopic (oxygen) and calcium carbonate (CaCO3), were performed on an AMS 14C dated core, 09 SG 13, collected from the Romanian Black Sea outer shelf (200 m water depth). The present study documents the changes that occur in the Black Sea from the Last Glacial Maximum towards the Present. In the 09 SG 13 core, two lithological units, respectively the youngest Unit 1 (The Coccolith mud) and the oldest Unit 3 (The Lacustrine lutite), were identified. The Unit 2 (The Sapropel Mud) is missing. In the two lithological units identified, four ecobiozones are distinguished based on changes in microfossil assemblages, which reveal climate shifts and oscillations of salinity. The Last Glacial Maximum period is characterized by stable conditions recorded by homogenous ostracod assemblages. However, the onset of the Fennoscandian Meltwater Pulses changed drastically the hydrological conditions of the basin, by lowering the salinity and allowing the fresh water ostracods to thrive. These fresh water pulses are mirrored in the sedimentary record by the reddish-brown clay deposition. This study documents also a core from the shallow area of the Black Sea inner shelf, MN 103_04 (78 m water depth). Based on macro and microfauna assemblages, this core reveals sea level changes that took place during the last approximately 6,000 yr BP. [ABSTRACT FROM AUTHOR]