Organic Geochemistry of Jurassic Sedimentary Deposits in the Sysola Shale-Bearing Region, Komi Republic

摘要

Data on 23 samples from Upper Jurassic sedimentary deposits in the Poing area, Sysola shale-bearing region, are reported. The deposits are characterized by wide ranges of orgnaic carbon content and kerogen composition. Aliphatic and polycyclic biomarkers of chloroformic bitumen A of the shales were analyzed in detail. For the first time, sterenes (unsaturated precursors of steranes) and their molecular-weight distributions in the bitument were time, sterenes (unsaturated precursors of steranes) and their molecular-weight distributions in the bitumen were identified and studied using chromatography-mass spectrometry. Our data on the distribution of biomarkers point to (1) protocatagenesis of the organic mater, (2) its deposition under reducing conditions, and (3) a mixed type of the initial organic matter.