The Structural Kinematic Process And The Type Of Basin-prototype Of Qaidamu Basin In Mesozoic-Cenozoic Era

Qaidamu basin is one of the most impotent oil and gas bearing basins in China northwestward.It is a Mesozoic-Cenozoic basin and has been explored for about 60 years. But the degree of exploration in Qaidamu basin is lower than other oil and gas bearing basins. There are a lot of oil fields in westward and northward of Qaidamu basin, so the degree of exploration is higher in western and northern portion than that in eastern portion.In this paper we carefully analyzed the previous work of other experts and particularly studied the structural evolvement, distortion pattern and the type of Mesozoic-Cenozoic basin-prototype of Qaidamu basin. We accomplished our research work through studying the sedimentary characteristic, surveying the structural form and analyzing the apatite and zircon fission tracks, especially the last one. We discussed the structural Kinematic process and the tectonic stress field of Qaidamu basin from the Yanshan movement and ascertained the type of Mesozoic-Cenozoic basin-prototype of Qaidamu basin; put forward the sedimentary and subsident center of the Qaidamu basin moved from the west to the southeast in Mesozoic-Cenozoic; and at last we made use of the information from the apatite and zircon fission tracks, based on the distribution diagram of the length and the distribution diagram of the age, we established the structural Kinematic process of Qaidamu basin in Mesozoic-Cenozoic era and demonstrated the time of the structural movement.From our research we obtained three pieces of the new cognitions: (1)Through the studying of the apatite and zircon fission tracks in the western down-fault zone and synthesizing the datum of the structural history and other geological datum in the Qaidamu basin, we put forward that there were three times structural movement in Qaidamu basin from Yanshan movement: late Jurassic-Cretaceous structural movement(160 ~65?Ma), Paleogene(or Eogene) movement(65 ~25?Ma) and the Neogene- Quaternary structural movement(20? Ma ~Nowadays); (2)We also put forward the switch of the structural Kinematic mechanism in Qaidamu basin and the structural Kinematic controls of the structural evolution and structural form in Qaidamu basin. (3)We ascertained the type of Mesozoic-Cenozoic era basin-prototype of Qaidamu basin in different stages: in Jurassic it is the separate fault block and subsidence in northward and in Jurassic- Paleogene(or Eogene) it is the extrusive basin with regard to the strike-slip, in Neogene- Quaternary Qaidamu basin is an integral down-warped settling basin.