上扬子地台及其邻区早、中三叠世间绿豆岩沉积前后古地理

以早、中三叠世间绿豆岩为等时面,分析其上下3m 的沉积相,共划分出9种岩石类型,分属5个沉积相带。西部为广阔的萨布哈台地,外圈为盐滩,内圈为干盐湖。东部沉积相呈带状分布,西为干化海湾;东为萨布哈盐滩和浅海海隆。

PALEOGEOGRAPHY OF BEFORE AND AFTER DEPOSITION OF GREEN-BEAN ROCK (ALTERED TUFF) BETWEEN THE EARLY AND MIDDLE TRIASSIC IN THE UPPER YANGTZE PLATFORM AND ITS ADJACENT AREAS

The sedimental facies of 3 m thick around the roof and bottem of the green-bean rock（altered tuff）between the Early and Middle Triassic can bedivided into 9 kinds of rock association,belonging to 5 sedimental facies zones respectively in the Upper Yangtze Plat form and its adjacent areas.The westpart of the studied region is a extensive sabkha platform,the facies zones aredistributed in circles.The outer part is constituted by purphish red clastic rock and massive dolomite of the sabkha;the middle circle consists of striped dolomite and anhydrite rock,striped magnesite,anhydrite intercalated with nodular polyhalite of salt playa;the inner one is made up of striped argillaceous anhy-drite rock.The sedimental facies of the east part are distributed as parallelribbon,which consists of striped argillaceous anhydrite rock,lamellar mudstoneand marl of desiccation bay in the west side,and massive gypsum microdolomite,micrite intercalated with oolitic limestone,dolomite of sabkha salt marsh andshallow sea in the east side.δ