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THE ROLE OF THE BYSKARIAN SERIES IN GEOLOGICAL STRUCTURE AND HISTORICAL DEVELOPMENT OF THE MINUSA TROUGH

V. I. Krasnov 1, G. S. Fedoseev 2,3, L. S. Ratanov 1

1 Siberian Research Institute of Geology, Geophysics and Mineral Resources; 2 V. S. Sobolev Institute of Geology and Mineralogy of SB RAS; 3 National Research Novosibirsk State University, Novosibirsk, Russia

The Byskarian series has been and remains the one of the most complex mappable lithostratigraphic subdivisions during the medium-small-scale State Geological Survey in the Altai-Sayan Region. Its composition displays the extreme facies variability of the continental Early Devonian formations of the Minusa trough. The typification of formations including in the series has been made on the material basis. It has been noted that the sedimentary-volcanogenic character of the Byskarian series should be changed to volcanogenicsedimentary, in connection with another assessment of quantitative relationships of the main formationcomposing components (terrigenous, volcanic and volcanogenic). It is established that the general chart of the Early Devonian magmatism in the process of the Byskarian series formation was antidromous as basite stratal bodies identified everywhere by way of lava paleoflows are actually sills and should be excluded from the series. In connection with this circumstance, the problem of the formation validity is touched on, in such formations stratal basitic bodies were erroneously referred formerly to effusive units. Also the problem of absence in the trough not only bimodal but also other volcanic series, which initial members are basalts and dolerites is broached.

Keywords: Byskarian series, Lower Devonian, basalt-dolerite sills, volcanoclastic rocks, Minusa trough, Krasnoyarsk Territory.

DOI 10.20403/2078-0575-2018-4-8-21