Most of the intracontinental foreland basins in western China were the results of intracontinental subduction (C-subduction)

which was a unique tectonic form in western China and developed in the conjunction areas between intracontinental folded mountain systems and foreland basins after the matching of the continents. Tectonics in mainland China resulting from matching of micro-continental blocks was the major cause of the complex structures of foreland basins in western China. Intracontinental subduction (C-subduction) was the intrinsic cause of circulation of mass flow and energy flow in type-C foreland basins and type-C orogenic belt (thrust belt). Closing of Tethys and continuous compressing and squeezing of Indian plate were the tectonic dynamics background for the formation of foreland basins in western China. The foreland basins in western China are very different from those typical foreland basins in respects of genetic mechanism

basin types

geologic features and hydrocarbon accumulation. Foreland basins of intracontinental subduction type (type-C) are characterized by continental source rocks

low poroperm sandstone reservoirs

various traps and multiple reservoiring stages mainly in Himalayan period.