MAGNETO- AND CARBON ISOTOPE STRATIGRAPHY OF THE LOWER-MIDDLE BATHONIAN of the SOKUR TRACT SECTION (Saratov, Central Russia): IMPLICATIONS FOR GLOBAL CORRELATION
O.S. Dzyuba1, A.Yu. Guzhikov2, A.G. Manikin2, B.N. Shurygin1,3, V.A. Grishchenko2, I.N. Kosenko1,3, A.M. Surinsky2, V.B. Sel’tser2, O.S. Urman1
1A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
2Saratov State University, ul. Astrakhanskaya 83, Saratov, 410012, Russia
3Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
Keywords: Bathonian, magnetostratigraphy, chemostratigraphy, Boreal-Tethyan correlation, paleotemperature, Russian Plate
Abstract
The Bathonian Stage in the Sokur Tract section on the periphery of the city of Saratov (Central Russia) contains both Tethyan and Boreal fossils. This makes the section a key object of research aimed at solving the problems of detailed correlation of the Bathoman between different paleobiogeographic provinces and calls for integrated studies involving both paleontological (based on different groups of fauna) and physicochemical (paleomagnetic and isotope-geochemical) methods. The results of study of carbon isotopes in belemnite (Cylindroteuthididae) rostra from the Sokur Tract section show that the Subboreal Oraniceras besnosovi Zone and Boreal Arcticoceras harlandi Subzone are correlated with the standard Zigzag Zone, whereas the Boreal A. ishmae Subzone is totally or mostly comparable to the standard Tenuiplicatus Zone. We have recognized analogs of the chrons of the geomagnetic-polarity time scale (GPTS): e-Bath N, M-Bath R, and lt-Bath N, corresponding to the Lower-Middle Bathonian and, possibly, lower Upper Bathonian.
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