PALEONTOLOGICAL CHARACTERISTICS, AGE, GEOCHEMISTRY OF ORGANIC MATTER AND PALEOENVIRONMENTS OF THE LOWER CRETACEOUS DEPOSITS OF THE BELAYA GORA SECTION (CENTRAL TRANSBAIKALIA)
I.N. Kosenko1, A.P. Rodchenko1, E.B. Pestchevitskaya1, E.V. Bugdaeva2, P.A. Yan1, V.D. Efremenko1, E.K. Metelkin1, O.S. Dzyuba1, B.N. Shurygin1, X. Teng3, D. Zheng3, B.L. Nikitenko1, V.A. Timofeeva, A.A. Kungurova1, E.P. Kopystka1, P.G. Borodin1, P.D. Kotler4,5, A.V. Kulikova4,5
1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far Eastern Branch of Russian Academy of Sciences, Vladivostok, Russia
3Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, Nanjing, China
4Kazan Federal University, Kazan, Russia
5Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Barremian, Aptian, Jehol Biota, Transbaikalia, fossil flora, spores and pollen, microfossils, geochemistry of organic matter, chemostratigraphy, U-Pb zircon dating
Abstract
The age of the Doronino Formation in the Belaya Gora section is defined as latest Barremian – earliest Aptian based on faunistic, floristic and microfossil assemblages. This age is also supported by the obtained δ13Corg curve, which correlates with most of the C2 segment and at least the beginning of the C3 segment of the Barremian-Aptian isotope curve. Results of the petrographic and geochemical analysis as well as microfossil studies showed that sediments accumulated in a shallow flowing lake with low-energy hydrodynamics. Climate features (seasonal temperate warm climate) and type of vegetation (coniferous forests with admixture of hardwoods) are reconstructed taking into consideration the composition of palynological and floristic assemblages.
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