Abstract:

Jurassic deposition was extensively developed in the northern Qaidam Basin. According to sequence stratigraphical analysis of outcrops, the Jurassic profile in the Dameigou area can be divided into 6 sequences. Sequences 1 and 4 consist of lowstand, water transgression and highstand systems tracts, and sequences 2, 3 and 5 consist of lowstand and transgression systems tracts. However, sequence 6 only consists of a lowstand systems tract. The development of depositional sequences is controlled by lake level changes and basement faulting, which continued to be active in the Jurassic. The result of sedimentarytectonic evolution research indicates that Qaidam Basin is fault subsidence. This kind of basin framework determined that the coalforming environment would occur in the north side of northern boundary fault of the Qaidam Basin and the south side of Lingjian fault, and the source rock would develop in the central subsidence belt between the two faults.

Key words: sequence, sedimentary-tectonic evolution, basement fault, Jurassic, Qaidam Basin