ISOTOPIC AND GEOCHEMICAL SURVEY OF POTENTIALLY OIL-AND-GAS SOURCE DEPOSITS OF THE RIPHEAN IN THE SOUTH-EAST OF THE SIBERIAN PLATFORM

Based on the study of the carbon and oxygen isotopic composition of the carbonate constituent of rocks (CCR) and carbon of dispersed organic matter (DOM), the facies conditions of sedimentation of the Middle Riphean Totinskaya and Malginskaya formations and Lakhandinian series of the Upper Riphean in the southeast of the Siberian Platform were revealed. The main isotopic criteria of the Middle Riphean domanicoid formation within the Aldan-Maya sedimentary basin of the Siberian Platform have been determined. The exogenous and endogenous factors necessary for the formation of domanicoid deposits of the Malginskaya Formation are considered. A mechanism leading to the formation of abnormally low 13C content in the Middle and Upper Riphean sediments with a range of –33.0...–35.0 ‰ is proposed. On the basis of isotopic data potentially-enable source-bed horizons within the Aldan-Maya depression are examined.