CALCAREOUS ALGAE AND LOWER BOUNDARY OF CAMBRIAN IN THE WESTERN ALTAI-SAYAN FOLDED AREA
A.A. Terleev, V.A. Luchinina, O.V. Sosnovskaya*, and G.N. Bagmet**
Institute of Petroleum Geology, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia * Krasnoyarskgeols'emka Enterprise, 3 ul. Berezina, Krasnoyarsk, 660020, Russia ** West Siberian Testing Center, Zapsibgeologiya Ltd., 7 prosp. Pionersky, Novokuznetsk, 654027, Russia
Keywords: Vendian, Cambrian, calcareous algae, small shelly fossils, Altai-Sayan Folded Area
Pages: 449-455
Abstract
New data are reported on occurrences of calcareous algae and other concurrent groups of fossils in the transient Vendian-Cambrian deposits of the western Altai-Sayan Folded Area (East Sayans, Gornaya Shoria, Kuznetsk Alatau, and Gorny Altai). There are two successive algal complexes: lower - with Korilophyton, Gemma, Razumovskia, Girvanella, Proaulopora, and Renalcis; upper - the same, supplemented with abundant species of the genus Epiphyton and with the genera Batinevia, Tubophyllum, and Subtifloria. These complexes are compared with the Nemakit-Daldyn (Upper Vendian) and Tommotian (Lower Cambrian) associations of algae of the Siberian Platform. A conclusion is made that the lower boundary of the Cambrian in the Altai-Sayan Folded Area can be tentatively drawn where the lower complex is replaced by the upper one. These inferences receive support from rare findings of small shelly fossils.
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