The Study Of Structure In Santanghu Basin

Santanghu Basin is located in the northeast of Xinjiang, which is a north-west extension intermountain basin. In order to study the fault and tectonic characteristics in Santanghu basin. In this research, to acquire the gravity and magnetic anomaly, analytical continuation anomaly map, the derivative anomaly diagrams overall level of anomaly map and the level of total gradient diagrams. According compare this maps to make the qualitative and quantitative calculations, compared with these basis of maps, combined with the data of earthquake, geology,well logging and results of previous studies. The two major faults are in NW direction, a series of NW, NNW, NE, EW and SN direction subsidiary faults in downwarping belt cut off the main faults; its structural framework of one depression between two uplifts resulted from long-term compressional stress within the basin, while as the influence of fault activity, made the downwarping region alternate with concave and convex. After the comprehensive research in Santanghu basin, the fault structure system and the pattern of structural unit have been speculated, the mainly results and conclusions which were obtained as follows:(1) Santanghu Basin have been suffered intense tectonic deformation, so the fracture is developed, The main fault was NW trending, most of the NW secondary faults are compressive faults, NE and near NS secondary faults are shear fault. The main fault controlled the formation of basin, and secondary faults control the formation of depressions.(2) The result of section fixed quantity calculation show that the effect of stress have different nature, different direction and different intensity lead to developed faults, These faults control the distribution and depth of the Mesozoic and Cenozoic sedimentary formation. The basement is the Carboniferous strata and the layer below the Carboniferous strata, the concave with the form of overthrust slice structure after a multiphase transformation(3) The Santanghu basin can be divided into three first grade structural units and five sub-first grade structual units. The three first grade structural units with a direction of NW show the macroscopic structural patterns of one downwarp between two uplifts as a whole. Two uplift belts have strongly structural deformations and nowadays the central abnormality area is the stable region. Between the sub-first grade structural units in the central downwarping region alternate with concave and convex, which is consistent with the structural p at t er ns o f th e S an ta n gh u ba s i n n o w. T h e lo ca l st r u ct u r al un it s em er g in g w it h m aj o r f au lt s ar e u su a l ly co nt r ol l e d b y th e f au l t s an d t h e m aj o ri ty o f it s tr a p s ar e a l so co n tr o ll e d b y th e fau lt s.