The organic matter of Aiyuvinsky oil shale deposit

The oil shales of Aiyuvinsky deposit are confined to the ammonite zone DorsoplanitesPanderi (J3v2). Maximum concentrations of organic carbon are fixed in the base of shale strata II and IV. The shales are characterized by Corg27.4-28.9 %. The specific feature of distribution of n-alkanes of oil shales bitumen from Aiyuvinsky deposit, although similar to shales from other sections of the Volga- Pechora shale province, is the dominance of odd n-alkanes in the medium (C15, C17) and high molecular area (С23, С25, С27 and С29). The Pr/Ph ratio in shales is significantly less than 1. The distribution of steranes testifies to predominant input of organic matter of plankton nature into the sediment with sometimes significant proportion of terrigenous (humus) material. The elemental composition of kerogen indicates that shales from Jurassic section of the Aiyuva river are characterized by the presence of II type kerogen. Unlike samples from Kashpir, Gorodishche, Sinegorye, Yb sections, the Aiyuva samples are characterized by the presence of isotopically lighter carbon. At the same organic carbon concentrations, δ13C values are 3-4 ‰ less than from other sections. Aiyuva oilshales contain organic matter, the origin of which is quite typical of oil shales from the Volga-Pechora shale province. Its formation is related to the accumulation of marine phytoplankton in sediments with possible small proportion of terrigenous organic matter