Volcanic rocks in the permian system sections of kuzbass

The issues of improving stratigraphic scheme of coal-bearing deposits of the Permian system of Kuznetsk Carboniferous trough are considered. It is shown that current version of the scheme, adopted in 1979 and formally compared with the national scale of the Permian system division, does not guarantee its reliability compared with the international scale. The main reason is endemicity of the fauna and flora of the Angarsk paleofloristic (and paleozoogeographic) region. This does not allow scientists to determining relative geological age of deposits using traditional methods. To solve the outlined problem, the authors propose to use radiological dating of zircons from volcanogenic-sedimentary formations (tonsteins in coal seams and ash tuff interlayers in terrigenous varieties of rocks of the coal-bearing strata). Wide distribution of such formations throughout the entire section of the Permian system of Kuzbass is shown. Despite the fact that presence of such deposits in the coal-bearing strata is not disputed, their number and position in the section remains unknown. In the current situation, it is proposed to start search and study of volcanogenic-sedimentary deposits from coal seams. Because of their extremely small thickness (a few centimeters), study of ash interlayers in the rocks hosting coal seams are supposed to be carried out along the way at the second stage of the coal-bearing section study. To facilitate the search for tonsteins, it is proposed to use the results of spectral analyzes for zirconium and, first of all, to focus on layers with abnormal and increased content. Such a correlation is confirmed by the example of tonsteins in seam XI of the Raspadskoye and seam 78 of the Talda coal deposit. Currently known absolute dates of tuffs at the base of the Maltsevskaya formation (20 m above the coal seam 103 of the Beregovoye section in the area of Babiy Kamen) show that the rocks belong to the Permian system, this leads to radical revision of the stratigraphic scheme of the entire section of the Permian system. The work we started made it possible to detect zircons in tonsteins of the seam 78 (the base of the Tailugansky regional horizon) and in the interlayer of ash tuff of the section of the Starokuznetsk horizon in the vicinity of Novokuznetsk (their dating is currently being completed). Implementation of the approach proposed by the authors to improve stratigraphic scheme of coal-bearing deposits of the Permian system of Kuzbass will enable obtaining of a framework of accurate absolute dating of almost all horizons of the regional scale, which will allow us to correlate it reliably with the national and international stratigraphic scale of the Permian system. Dating can also be used for intra-regional correlation of sections of different geological and economic regions of Kuzbass.