Abstract:The stratigraphy of the Taman Peninsula is defined using the sections at Zelensky Hill -Panagia, Popov Kamen, Taman and Zheleznyi Rog. The stratigraphy is constructed from distribution of mollusks, foraminifers, nannofossils, diatoms, and organic-walled phytoplankton, as well as incorporating paleomagnetic data. The occurrence of oceanic diatom species in the Middle-Upper Sarmatian, Maeotian and Lower Pontian makes a direct correlation possible between the sections studied, the Mediterranean basin and oceanic zonation. The new data on planktonic and benthic biotic groups suggests a pulsating connection of the Eastern Paratethys with the open marine basins, especially during transitional intervals within constant environments. Comprehensive studies of the Chokrakian-Kimmerian microbiota provide evidence for several levels of marine microbiotic associations that are related to short-term marine invasions. The biotic and paleomagnetic data of the Taman Peninsula sections give a more comprehensive, but sometimes a controversial picture on the Eastern Paratethys history and the nature of its relationship with the adjacent marine basins.
Three sections (Taman, Popov Kamen, and Zheleznyi Rog) of the Upper Maeotian-Lower Pontian sediments of the Taman Peninsula (Eastern Paratethys) have been studied. The sequences represent continuous successions of the Maeotian and Pontian sediments. The transitional Upper Maeotian-Lower Pontian relatively deep-water sediments were formed at the time when Eastern Paratethys was connected with other marine basins. The facies are represented by thin clay layers interbedded with laminated diatomites and contain unusual diatom and nannofossil associations. The small size of coccoliths and the absence of zonal markers indicate that the influx of marine waters took place in the stressed conditions of a restricted basin. Diatom assemblages are more diverse and include the open-marine species Azpeitia aff. komurae and Thalassiosira maruyamica and marine endemics Actinocyclus aff. paradoxus, Rhizosolenia bezrukovii, Hemiaulus sp., Nitzschia miocenica of the tropical Nitzschia miocenica Zone and -the index species of next Thalassiosira convexa Zone appear in these part of the sections. Three stages of the Mediterranean marine invasion are distinguished; during the first one the connection between basins was rather permanent, for the two others its character became pulsing and not stable. The possible duration of the invasion is estimated from 6.4 to 6.1 Ma and belongs to the Early Messinian -to pre-evaporate deposits and lower part of lower evaporate deposits.
Past hydrological interactions between the Mediterranean Sea and Black Sea are poorly resolved due to complications in establishing a high-resolution time frame for the Black Sea. We present a new greigite-based magnetostratigraphic age model for the Mio-Pliocene deposits of DSDP Hole 380/380A, drilled in the southwestern Black Sea. This age model is complemented by 40 Ar/ 39 Ar dating of a volcanic ash layer, allowing a direct correlation of Black Sea deposits to the Messinian salinity crisis (MSC) interval of the Mediterranean Sea. Proxy records divide these DSDP deposits into four intervals: (i) Pre-MSC marine conditions (6.1-6.0 Ma); (ii) highstand, fresh to brackish water conditions (~6.0-5.6 Ma); (iii) lowstand, fresh-water environment (5.6-5.4 Ma) and (iv) highstand, fresh-water conditions (5.4-post 5.0 Ma). Our results indicate the Black Sea was a major fresh-water source during gypsum precipitation in the Mediterranean Sea. The introduction of Lago Mare fauna during the final stage of the MSC coincides with a sea-level rise in the Black Sea. Across the Mio-Pliocene boundary, sea-level and salinity in the Black Sea did not change significantly.
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