CAMBRIAN GASES, OILS, AND CONDENSATES IN THE AREAS OF INTENSE FLOOD-BASALT MAGMATISM WITHIN THE SIBERIAN PLATFORM

This article deals with the composition and characteristics of gases, oils, and condensates from the halmeic-sulfate-carbonate sedimentary c omplex of the South Tunguska petroliferous region, one of the regions of the Siberian platform where flood basalts are abundant. It is shown that the investigated fluids, especially condensates, can be classifi ed as a separate group of hydrocarbons (HC), distinguished by a high s ulfur content and significant concentrations of aromatic HC in low-boi ling fractions. An analysis of the province evolution provides evidenc e that the reactivation of flood-basalt magmatism (in the Late Permian -Early Triassic) was the governing factor in shaping the present-day p etroleum potential of the western part of the Siberian platform. Uneve n distribution of intrusions within the sedimentary cover resulted in the formation of an unusual kind of zoning, wherein the transformation of HC fluids does not follow the usual patterns.