Composition of Middle Riphean Strelnye Gory Formation Bitumen–Turukhansk Uplift–Lower Tunguska River

The Turukhano-Norilsk ridge, Siberian platform, is the area of Paleozoic and Precambrian natural outcrops. Several fields and bitumen shows dated to the caverns and fissures are discovered within its limits, that testifies on present oil and gas systems in the study area. One of the main objects for characterization of petroleum systems is determination of source rocks. The Strelnye Gory formation (Middle Riphean) is one of most enriched in organic matter and could be considered as one of major source formations in the north-western part of the Siberian platform. TOC volumes in the claystones are in average 1.2 %, in separate samples reaching up to 3.4-4.2%. High maturity level of these deposits gives the opportunity to conclude that these concentrations are residual. Initial TOC values have been evidently 2-3 times higher, that is characterizing the studied deposits as highly enriched source rocks. Different forms of organisms took part in formation of petroleum potential of these rocks. In Late Strelnye Gory time the benthic forms appeared. This statement is made based on the study of n-alkane distribution. The view of n-alkanes distribution in the bitumen of source rocks gives the opportunity to draw correlations «oil – source rocks»