CHARACTERISTICS OF THE WAVY MOSAIC STRUCTURES AND THEIR CONTROL OVER THE OIL AND GAS FIELD IN THE QAIDAM BASIN

The frameworks of the wavy mosaic structure of the Qaidam basin were formed by the crossing of the NE-trending outer-pacific structural belts and the NW-trending paleo-Mediterranean belts, on which overlapped the EW and NS trending structures, and thus makes the structural frameworks complicated, wherein the NW-W trending is dominant. In the basin, the NW-W and NE trending structural belts can be subdivided into the second-order and third order crest and trough belts. The Qaidam basin is a stable ancient massif. It was principally a rise before Mesozoic. experienced the stage of minor rift-depressions during the Jurassic and Cretaceous period, and developed gradually into a large scale sedimentary basin of the present-day. An counter-clockwise rotation of the depocentre in this basin took place during the development of the crust-wave. The developments of the crustal movements like waves advancing one upon another and the frameworks of the mosaic structure in the Qaidam basin were in control of the stratigraphic thickness, facies-paleogeography, geological history and structural characteristics, and the distributions of various deposits including oil and gas deposits. This paper discusses these controls in details and evaluates the oil and gas potentials of the basin as a whole.