Santanghu Jurassic Sedimentary System

SanTangHu Basin, about 2,300Km2, is situated on the northeast edge of mid-asia. Hills and gobi are the main physiognomy. SanTangHu depression and NoMaoHu depression spread in the Basin. The climate is the classical continental climate.The north part of Xinjiang which SanTangHu Basin is lied in is the important part of mid-asia orogentic belt and has been charged by many tectonic movements, Which is influenced by Mesozonic-Cenozonic era Tethyan structure, during the development of later Palaeozonic era-Mesozonic-Cenozonic era incontinental sedimentary basin. The Jurassic period all strata can be drilled and the outcrop can be found in the basin. The Jurassic period strata is composed of Sangonghe-Badaowan Formation, Xishanyao Formation, Toutunhe Formation, Qigu Formation, The lithology of the trata is mainly sandstone and claystone, and there are abundant of ostracales miscrofossils in the strata.The strata subsidence character and the subsidence history of TiaoHu depression and maLang depression was simulated based on the sediment filling pattern,compaction correction pattern and crustal equilibrium pattern by computer. The study shows that the basin is subsidenced in the early Jurassic period and the sedimentation center lied in Tiaohu depression. When it comes to the middle Jurassic period, the subsidence center and the sediment center moved to the Malang depression. During middle-later Jurassic period, the basin subsided stably and the center of sediment and subsidence still lied in Malang depression.The study showed that the sediment of the Jurassic period was all from hills of the two sides of the basin and the composition was complex. In the basin, there were some different sedimentary systems-River sedimentary system, lake sedimentary system, the delta sedimentary system, fan delta sedimentary system and alluvial fan sedimentary system. There is the different system in the different period. It was mainly river sedimentary system in early Jurassic period, lake sedimentary system and delta sedimentary system in middle-later Jurassic period and there are fan delta sedimentary system and alluvial fan sedimentary system in the edge of basin.The whole Jurassic period SanTangHu basin was undergone a sedimental cycle: river-lake-river, the environment changed from warm-wet to drought.