干旱区生态环境知识资源中心

The Qiangtang catchment basin is a large Mesozoic marine sedimentary basin located in the plateau of the northern part of Qingzang, where multiple evaporation sets are being developed. On site observation and thin section investigation, the evaporation of Buqu formation mainly includes slab tower dolomite gypsum rock with wire structure of gypsum, salt rock and poultry houses. Two calcareous association types were identified in Buqu formation, including desert-type macroporous limestone - dolomite - gypsaris and mineral - carbon mudstone - gypsaris. The former was deposited on the carbonate lagoon setting and the latter was deposited in the local closed gulf setting. Two deposited sequences containing Buqu sequence 1 and Buqu sequence 2 were distinguished. Gypsum and carbonate salt lake mainly appear in the Lowstand system tract (LST) of Buqu sequence 1 and Buqu sequence 2, and gypsum and salt of locally closed ores are mainly composed of Highstand system tract (HST) of Buqu sequence 2. It is possible to judge from anhydrous gypsum, salt distribution and sediment distribution to find the most advantageous storage place for seawater hydrocarbon exploration. The investigation of evaporites in the middle Jurassic Buqu Formation of Qiangtang is in favour of the exploration and development for fossil energy in the future.