THE PRE-DANILOVSKY BREAK IN THE UPPER VENDIAN SECTION OF THE BAIKIT ANTECLISE AND THE EAST OF THE ANGARA ZONE OF FOLDING

N. V. Melnikov

Siberian Research Institute of Geology, Geophysics and Mineral Resources, Novosibirsk, Russia

The division of the Upper Vendian formations into members and layers at the Ilbokichskaya area (the northeastern termination of the Angara zone of folding, the western Siberian Platform) established the presence of the pre-Danilovsky break and the amplitude scouring of deposits. In the Katangskaya Formation of the Danilovsky horizon, overlying the break, the lower part is composed of the carbonaceous Preobrazhenskaya member and the basal Ilbokichskaya member of argillaceous dolomites and marls. The thickness of the members increases from the north (the Baikit anteclise) to the south in the Angara zone of folding. Under the break in the north (the Baikit anteclise), there is no Moshakovskaya Formation and the upper members of the Oskobinskaya and Chistyakovskaya formations of the Tirsky horizon. To the south, the thickness of the formations increases, and apparently there is no break at the Agaleevskaya area of the Angarskaya zone of folding. The Ilbokichskaya member there occurs in the uppermost Moshakovskaya Formation, but pertains to the Danilovsky horizon. The Moshakovskaya Formation includes the upper Tirsky and the lower Danilovsky horizons. In general, there is a typical geological model of the structure of stratigraphic bodies in the areas of a rapid increase in amplitudes of tectonic downwarping.

Keywords: pre-Danilovsky break, Upper Vendian, Baikit anteclise, Angara zone of folding.

DOI 10.20403/2078-0575-2017-3-22-28 ​

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