Organic Carbon Distribution in Cambrian Deposits of the cis-Yenisei Subbasin

—The study considers the distribution of organic carbon in different formations and facies of Cambrian age identified in the cis-Yenisei subbasin. Two groups of depositional environments were recognized in the deepwater perioceanic and epicontinental basins, which accumulated sediments with elevated and sometimes anomalously high concentrations of planktonic and benthic organic matter. These are 1) local centers in the Tommotian (Oksym Formation) and Botomian stages of the lower Cambrian, Mayan (Elogui and Pudzhelga formations) and Ayusokkanian (Kondes Formation) stages of the middle Cambrian; 2) regional Kuonamka horizon, which is composed of Toyonian and Amgian deposits and occurs along the margins of the Siberian Platform; it is represented by the Inikan and Kuonamka formations in the east of the Siberian Platform and by the Paidugina Formation in the study area. The study shows that the organic matter has undergone a high degree of transformation and reached the apocatagenesis grade. The results of the study assume that the hydrocarbon generation intensity was high in the Cambrian formations of the cis-Yenisei subbasin in the geological past.