Search

Paleogeography and depositional environments in the zone of junction of the Crimea and the Greater Caucasus, as well as adjacent areas of the West Kuban Basin, the Sea of Azov and the Western Ciscaucasia are described based on the results of drilling works, seismic studies and multidisciplinary research. Paleogeographic maps are compiled for the early Oligocene, middle Miocene (Karaganian and early Sarmatian) and late Miocene (late Maeotian and early Pontian). The maps represented show gradual sediment filling of the deep West Kuban trough during the Maikopian and middle Miocene, and its gradual closure in the Kerch-Taman area. The deep-water connection of this trough with the Black Sea basin through the Sorokin trough had been closed by the mid-Sarmatian. The entire Kerch-Taman region became shallow by the end of the Maeotian. Significant sea level falls occurred at the end of the Tarkhanian and Sarmatian as well as in the middle of the Pontian. Large erosion channels from these times are traced on the geological and seismic profiles of the northern Scythian shelf. • Paleogeographic maps are compiled for early Oligocene, middle Miocene (2) and late Miocene (2). • The maps show sediment filling of West Kuban trough and closing in Kerch-Taman area. • Erosion incisions are result of two significant sea level falls. [ABSTRACT FROM AUTHOR]

This study presents new data on the orbitally calibrated Maeotian/Pontian and Pontian record of the Black Sea Basin (Paratethys) obtained by time-series analysis of magnetic susceptibility (MS) data from relatively deep-water Upper Miocene sediments exposed in the Zheleznyi Rog section (Taman Peninsula, Russia). In the studied interval, a ∼145-m-long sedimentary sequence, spectral analysis revealed statistically significant signals with 6.1–8.2 m and 3.0–4.0 m wavelength. These signals correspond to the obliquity and precession cycles, respectively. This study correlates the main steps of Messinian Salinity Crisis (MSC) of the Mediterranean to the Black Sea Pontian record based on astronomical tuning of the study sequence and evaluation of integrated biostratigraphic, paleomagnetic and sedimentological data. Based on cyclostratigraphic results, Maeotian/Pontian beds with Actinocyclus octonarius accumulated from ∼6.3 to 6.1 Ma. Most of the Novorossian sediments correspond to the first MSC step. The TG 22 (5.79 Ma) and TG 20 (5.75 Ma) glacial events occur in the uppermost Novorossian record and are marked by extraordinary high values of MS. The Portaferian, dated at the base as ∼5.65 Ma and the top as ∼5.45 Ma, corresponds to the second MSC step. The Novorossian/Portaferian transition is marked by the hiatus of approximately 150–160 kyr, which agrees well with the concept of the intra-Pontian unconformity in the Black Sea Basin and a sea-level drop in the Mediterranean from 5.6 to 5.46 Ma. The ages for the base and the top of the Bosphorian were estimated as ∼5.45 Ma and ∼5.27 Ma, respectively. The base of the Bosphorian corresponds to the third Lago Mare episode caused by the high sea-level connection between the Mediterranean and Eastern Paratethys. [ABSTRACT FROM AUTHOR]