ON CONTINENTAL DEPOSITIONAL PATTERN OF OIL AND GAS BASINS IN CHINA

According to the depositional conditions,the Weso一Cainozoic continental sedi-ments are suggested to be divided into three kinds of environment in 12 facics:(1)Underwater depositional environment including deeplake facies,semi-deep lake facies,shallow lake facies.near-lake facies,salt lake facies and turbiditc facies;(2)transitional depositional environmeat including deltaic facies and marsh facics;(3)Subaerial depositioaal environment including fluviatile facies,pluvial facies,piedmont facies and aeolian facies.A map of depositional pattern for some of the Meso-Cenozoic oil and gas basins in China is、worked out based on the distribution of sedimentary facies of their oil-bearing rock series.The study of the continental depositional patterns of any oil and gas basins is of great significance to their exploration.Oil pools in any basins occur mostly in the oil-generation depressions and their environs,while the deep-lake facies and the semi-deep lake facies are both the region of distribution of source rocks and the center of deposition.so the research work serves as a useful guide to the discover of oil.丁he author believes that climate and tectonic movements are the two factors controlling the distribution and development of sedimentary facies.As for the tectonic movement occurring in the Meso一Cenozoic time,the author tries to classify the basins into three types:compressive, tensile and transitional,and gives a brief description of the distributional characteristics of sedimentary- facies in various types of basin.