STRUCTURAL CHARACTERISTICS OF THE JURASSIC BASIN IN THE WEST PART OF THE NORTHERN MARGIN OF THE QAIDAM PLATE AND THEIR EVOLUTION

The Jurassic distribution was controlled by NW-trending and near EW-trending structures in the west part of the northern margin of the Qaidam Plate.Near EW-trending structures zoned the Jurassic from north to south,and NW-trending structures divided the Jurassic into some blocks from west to east.Several thickness centers formed because of the controlling of NW-trending and near EW-trending structures.The Early-Middle Jurassic basin was an extensional faulted basin,in which major hydrocarbon source rocks were deposited.And the Late Jurassic-Cretaceous basin was a compressional basin.From the Early Jurassic to the Cretaceous,strata deposition migrated from south to north and from west to east.The deposition of the Cenozoic basin superposed on the Jurassic basin played an important role in the pre-servation of the Jurassic,and promoted oil and gas generation.Structure deformation and combination of the Cenozoic provided favorable conditions for the oil and gas pool formation of the study area.