The Siberian Craton covers an area of about 4.5 million sq. km in northern Russia, of which up to 3.5 million sq. km may be prospective for hydrocarbons. The craton was consolidated in the Early Proterozoic. and above the basement granitoids and gneisses is a variable thickness of sedimentary strata ranging in age from Riphean (Middle-Late Proterozoic) to Quaternary. Reservoir rocks are known to occur in the interval between the Middle Riphean and the Upper Cretaceous; those of Riphean age have produced oil commercially since 1973. Geochemical data indicate that the oil within the Riphean reservoir rocks was generated by source rocks of Riphean age. Riphean reservoir rocks include both carbonates and siliciclastics, but commercial volumes of hydrocarbons have only been discovered within the carbonates. Three petroleum-bearing "provinces" or megabasins are located on the Siberian Craton: Lena-Tunguska, Lena-Vilyuy and Yenisey-Anabar. The Yurubchen-Tokhom Zone in Lena-Tunguska Province is potentially the most important oil-producing area in the craton, and comprises a number of distinct fields. Reservoir rocks here consist principally of thick Riphean dolomites. Both the development of reservoir characteristics within these dolomites and the formation of stratigraphic traps are related to an episode of emergence and karstification at the end of the Riphean.