On peculiarities of composition and properties of ancient hydrocarbon source rocks

Precambrian rocks are widespread within all continents of the Earth; that said, sedimentary associations of these deposits are of special interest in search for oil and gas fields. A wide range of paleontological, lithological and geochemical methods is utilized for conducting integrated geological-geochemical analysis and evaluating the initial hydrocarbon generating potential of organic matter of Precambrian source rocks. Investigated were peculiarities of depositional environments of the organic matter, specific features of its composition in sedimentary rocks and its generation characteristics. Own research efforts were performed in combination with generalization of other authors’ publications focused on Precambrian sequences enriched in organic matter – their occurrence, isotopic and biomarker characteristics and realization schemes of the hydrocarbon generation potential of Precambrian organic matter in the process of catagenesis. Geochemical peculiarities of initial organic matter are illustrated on various examples, type of the organic matter is determined together with the character of evolution of realization of its initial generation potential.