Sediment provenance analysis of the 8th member of the upper Paleozoic Xiashihezi formation in the southwest area of Ordos basin

With the successive discovering of clasticrock oil-gas reservoirs in Permian of upper Paleozoic in the southwest area of Ordos basin,special attention has been paid to the material sources of these reservoirs.By applying mathematical statistics and in combination with the debris composition,the distribution characteristics of heavy minerals and paleocurrent direction,the source areas of the 8th member of the Xiashihezi formation of Permian in the region have been analyzed in contrast with native rocks.The analysis results show that three provenance exist in the studied area.The provenance of north of the basin is derived from the Archean sedimentary metamorphic rock and the sex volcanic rocks of Yinshan paleoland,the provenance of the southwest of the basin is derived from the senior metamorphic rocks and part of magmatic rocks and a small amount of sedimentary rock of north Qilian and west Qinling and the provenance of the south of the basin is derived from senior metamorphic rocks and part of magmatic rocks and a small amount of sedimentary rock of north Qinling.Besides,three provenance approximately intersect the Huan county-Huachi area.The problems existing in the research on the material sources of upper Paleozoic in the southwest area of Ordos basin not only have been settled,a certain reference to research the sediment provenance of the basin in other parts of the Xiashihezi formation of Permian has been offered as well.