ASSESSMENT OF MESOZOIC SOURCE ROCKS AT THE MARGIN OF SOUTH CHINA CONTINENT

The total thickness of the Upper Triassic and Cretaceous are over 10000 meters around the margin of South China continent. No oil seepage has been discovered so far on outcrops. The source rocks are mainly composed of mudstones, carbonaceous mudstones and coal seams. The organic matter is of typeⅡ-Ⅲ. High quality source rocks, which contain 1.17%~5.43% of TOC, have been found in the deep marine deposits of the Xiaoshui Formation of Upper Triassic. The Bianqiaoyuan Formation of Lower Jurassic is a transitional facies, where source rocks have been found with 1.36%~10.37% of TOC. In other Formations of Lower Jurassic there are rocks of neritic -bathyal marine facies with 0.5%~1.76% of TOC. The source rocks are now matured or over matured. Among them, the source rocks in the Xiaoshui Formation and Lantang Group are the best with regard to the high TOC and big thickness. In addition to the Mesozoic source rocks in Northern South China Sea, the source rocks around the margin of South China must be taken into account.