Abstract:

Studies show that the ancient tectonic environment controlled not only the formation and development of Tarim Basin,but also imposed apparent influ-ence on various typical lithofacies of Triassic-Jurassic sediments,for example,the Baicheng and Xinan half-graben depressions,are characterized by narrowlitho facies near the steep escarpments and wide spread lithofacies in shallowslopes;the Tadong downwarping depression is characterized usually by con-centric distribution of lithofacies;while the Minfeng-Jianggesha fault-troughis characterized by symmetrical distribution of lithofacies.On the steeply down-warped side of the half-graben,sediments are predominated by arenaceous-conglomeratic,proluvial and fan-deltaic facies,while on the shallow slope side,they are mainly deltaic,alluvial and shallow water lacustrine facies.Sediments of the fault-trough depression are represented by proluvial and fan-deltaic facies with great number of arenaceous-conglomeratic materials on both sides nearescarpments.Sediments in downwarped region are composed of fine-grained clastics with wide spread deltaic and alluvial facies and a large area of deepwater depocenter.Stratigraphic traps can probably be found in the outer marginof a deltaic structure and tributary channel in the domain of the downwarping region.Traps relative to the proluvial fan-delta might be characterized by fault trough.Whereas in the steeply warped side of the halfgraben,the stratigraphic traps might be discoverd within fan-deltaic and turbidity sediments;while in the gentle slope,traps can mainly develop in the tapering updip sandstones.