Geochemical particulars of "immature" hydrocarbon accumulations pelagic fachcses
Geochemical particulars of "immature" hydrocarbon accumulations of pelagic facieses are examined in the present article. The accumulations of the following pelagic facieses with sapropel OM are studied: terrigenous-siliceous - oils of Sakhalin, W. Kamchatka, Japan, California and terrigenous-carbonate - oils of Pripyat trough of Belorussia and Australia. The various genetic indices of hydrocarbon and trace element composition are attracted. It is demonstrated that the following chemical types of oils are characteristic for investigated HC accumulations: for terrigenous-siliceous facieses - A-2 and A'-l, for terrigenous-carbonate facieses - B-2 and A<sup>b</sup>-1. In the most of oils low concentrations V and Ni; the predominance Ni over V; the straight correlation dependence between these elements are observed. However, in heavy and sulphureous oils of California, which generated OM of Monterey formation, more high contents V and Ni are revealed as compared with oils of other regions. This fact is explained by more reductive conditions of sedimentary environments.