Study on Tectonic Evolution of Junggar Basin

Junggar Basin is one of the biggest oil and gas bearing basins in China. Junggar Basin lies among the Altaiorogen on south flank of Siberia plate, the Kazakstan plate and the Tianshan fold belt. It is a Late Paleozoic, Mesozoic, and Cenozoic compressional superimposed basin, experienced the effects Hercynian orogeny, indosinian, Yanshannian and Himalayan orogenisms and was rsulted in a complex tectonic frame work. Junggar Basin developed on the basis of Junggar terrain. The terrain consists of Precambrin crystal basement which was formed before 800Ma at least. It consists of dual basement and four-layers structure. The crust thinning took place in some parts of the basin. So, the evolution falls into two stages i. e. the first stage, the evolution of the Junggar terrane and the second stage, the evolution of the basin. During the whole Lower Paleozoic, the terrane was in the stable evolution of the terrane. The terrain passed through three stages and came into being the Junggar Basin: (1) the terrane evolution; (2) the oceanic crust comsumption; (3) the accretion and collage of the terrain and the plates. Based on the structure-layers and the progress of the basin research, the formation and evolution of the J unggar Basin has divided into six stages: (1) the formation of the terrain; (2) the evolution of the terrain; (3) the collage of the terrain and the plates and the formation of the enbryonic; (4) foreland basin stage; (5) the intacontinental depression stage; (6) the regeneration foreland basin. The latter three stages are related to the accumulation of petroloum and nature gas.