Download PDF

ISOTOPIC-GEOCHEMICAL RESEARCHES OF ORDOVICIAN AND LOWER SILURIAN SEDIMENTS OF THE NORTH-WESTERN PART OF THE SIBERIAN PLATFORM

S. I. Golyshev 1, P. N. Sobolev 2, N. L. Padalko 1, P. F. Yavorov 1, E. V. Chernikov 1, M. I. Prazdnichnykh 1

1 Tomsk branch of the Siberian research institute of geology, geophysics and mineral resources, Tomsk, Russia; 2 Siberian research institute of geology, geophysics and mineral resources, Novosibirsk, Russia

Based on the isotopic composition of dispersed organic carbon (DOM) carbon and carbon and oxygen in the carbonate component of rocks, the facies features of sedimentation in the Ordovician and Lower Silurian deposits of the northwestern part of the Siberian Platform are revealed. It has been established that in the deep-sea marine, coastal-marine facies, DOM of isotope-light composition is formed, which is typical for type II kerogen, and in shallow and coastal facies, DOM of isotope-heavy composition is present, which is characteristic of humic type III kerogen or oxysorbosapropelites. In graptolitic schists of the Lower Silurian, the isotopic composition of the carbonate component with small variations reflects a stable sedimentation regime in the deep sea basin and low temperature environment.

Keywords: biocenosis, graptolites, isotopic composition, carbonates, oxygen, sedimentation, Ordovician, sediments, dispersed organic matter, regimes, Silurian, carbon, facies.

DOI 10.20403/2078-0575-2020-2-81-86