LITHOSTRATIGRAPHY, FACIES AND ICHNOFOSSILS OF LOWER- LOWER PART OF MIDDLE ORDOVICIAN OF THE TELETSKOE LAKESIDE ALTAI
N.V. Sennikov1,2, O.T. Obut1,2
1Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: Lower and Middle Ordovician, terrigenous red-color strata, Teletskoe Lakeside Altai, litho- and ichnofacies.
Abstract
Bed-by-bed description of five mainly red-colored terrigenous sections of the lower Ordovician sedimentary complex of the Teletskoe Lakeside Altai is presented. Only ichnofossils were discovered, whereas in the overlain (Darriwilian) strata taxonomically diverse trilobite, ostracod, brachiopod, nautiloid, gastropod and conodont assemblages were recovered. The two new Kalychak –Izhun and Kalalu Bodies characterized by basal conglomerates were defined. The lower body unconformably overlain with a huge stratigraphic gap the Lower Cambrian effusive-terrigenous and carbonate sediments, and the upper Kalalu Body overlain the Kalychak-Izhun Body with azimuthal unconformity. The analysis of lithology has revealed numerous phenomena indicating the formation of the Kalychak-Izhun and Kalalu sediments in eolian (dune), lake, river, and delta facies environments. Ichnofossils recovered from the upper part of the Kalalu Body confirm the conclusion about the continental and transitional to marine sedimentary environments for these two red-colored terrigenous strata.
According to defined stratigraphic succession Kalalu Body with some degree of convention, is aligned with the lower part of Middle Ordovician (Dapingian), and underlain Kalychak-Izhun Body, also conventionally, with the upper part of Lower Ordovician (Floian).
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