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The composition and distribution of phenanthrenes (polyaromatic compounds) have been studied in chloroform extracts from dispersed organic matter (OM) of clayey, siliceous, carbonate, and terrigenous rocks of different ages and facies and from some oils of the Siberian Platform. Phenanthrenes have been analyzed by gas chromatography–mass spectrometry. High contents of 1,7,8-trimethylphenanthrene and 1,1,7,8-tetramethyl-1,2,3,4-tetrahydrophenanthrene are present in the OM of Vendian and Cambrian carbonate-shale deposits and in ancient oils of the Nepa–Botuobiya and Anabar anteclises. The OM of Permian continental deposits and oils of the Vilyui syneclise is dominated by 1-methyl-7-isopropylphenanthrene (retene). A triangular diagram for identification of the types of original OM of rocks and classification of genetically related oils has been constructed based on the assessment of phenanthrene biomarker distribution. Putative pathways of the formation of phenanthrene biomarkers are discussed.

The results of comparison geological-geochemical study of the Upper Jurassic-Lower Cretaceous sediments of the Preverkhoyansky and Indigiro-Zyryansky basins are considered from the positions of uniform sedimentary basin evolution. Based on lithologic-petrographic data the differences were established in the catagenetic transformations degree of the organic matter (OM) of the Upper Jurassic-Lower Cretaceous deposits from MC3 within the Preverkhoyansky basin and up to MC5 - in the Indigiro-Zyryansky. The distinctions are due, mainly, by a post-collision stage of development of the territory of the Indigiro-Zyryansky basin. The geochemical characteristic of organic matter is given. The identity of composition and distribution of hydrocarbons-biomarkers indicates a common source of the initial OM formed in the conditions of continental facies in the Preverkhoyansky basin. Contrary, OM accumulation of the Upper Jurassic deposits of the western part of the Indigiro-Zyryansky basin occurred in sea and lagoon facies. OM enriched by sapropel material that indicated more oil generation potential of rocks. Based on analysis of the received results the map of prospects of oil-and-gas bearing with allocation of sites for conducting prime exploration works on oil and gas is constructed for the Upper Jurassic-Lower Cretaceous deposits of the Preverkhoyansky and Indigiro-Zyryansky basins.

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