The Late Mesozoic-Cenozoic Sedimentary Basins at the Continental Margin of Southeastern Russia: Geodynamic Evolution and Coal and Petroleum Potential

摘要

The diverse geodynamic settings of the intraplate riftogenic, convergent, and transform origin existed in eastern Russia in the Late Mesozoic and Cenozoic. In the Late Triassie-Early Jurassic, a thick accretionary prism was formed in the convergence zone between the Izanagi-Farallon and Eurasian lithospheric plates, whereas the rigid cratons located westerly were framed by spacious shelf seas populated by diverse fauna and filled with terrigenous sediments. The Middle Jurassic collision of the Siberian and Chinese cratons was followed by formation of postcollision sedimentary basins extending along the Mongolian-Okhotsk Suture. These basins were filled with terrigenous coal-bearing molasse in the west and with near-shore marine sediments in the east (Uda and Torom basins). The disintegration of Pangea and opening of oceans in the Late Jurassic are correlated with the northeastward motion of the Farallon Plate and formation of a roughly N-S-trending rift system at the Asian margin, along which the Songliao and Amur-Zeya basins started to subside. The Andean-type continental margin existed at this time in the east. The margin of the Bureya-Jiamusy-Khanka Superter-rane was rimmed in the Late Jurassic by foreland basins (Bureya, Partizansky, Razdol'ny) and the flexure-shaped Sanjiang-Middle Amur Basin. In the Valanginian-middle Albian, oblique subduction of the Izanagi Plate controlled formation of the transform margin, reactivation of left-lateral displacements, and formation of pull-apart basins filled with turbidites. In the Aptian, reorganization of lithospheric plates' motion resulted in formation of epioceanic island arcs, as well as forearc (in the western Sakhalin) and backarc (in the Sikhote-Alin) basins that accumulated coal-bearing sediments enriched in volcaniclastic material. In the mid-Albian, the terranes accreted to the continent, granites were emplaced, and the imbricate structure was formed. In the Late Cretaceous, the frontal subduction of the Kula Plate resulted in formation of the East Sikhote-Alin volcanic belt. The shelf terrigenous sediments continued to accumulate in the fore- and backarc basins while the rift stage in intracontinental basins gave way to the stage of postrift subsidence (Amur-Zeya Basin). The general regional uplift took place in the Maastrichtian. Extension with a substantial strike-slip component dominated in the Cenozoic, as is evident from a system of grabens traceable from China to the Sea of Okhotsk. The grabens are filled with lacustrine-fluvial sediments that host coal and petroleum fields and occurrences.