鄂尔多斯盆地西南部地区盒八段物源区分析及划分

Analysis and Identification of Provenance of 8^(th) Member of Shihezi Formation in the South-western Ordos Basin

通过对古水流方向、砂岩碎屑组分、岩屑组合、重矿物特征及粒度等的综合分析,结合盆地周边露头剖面的研究,对鄂尔多斯盆地西南部地区石盒子组八段的物源及其母岩特征进行了深入剖析。结果表明:研究区可划分出3个物源区,即西南部、南部以及北部,西南部的沉积物物源主要是来自盆地西南缘的北祁连、西秦岭等地,而南部的沉积物物源主要来自北秦岭地区,北部的沉积物物源区为盆地北缘的阴山地区。

A comprehensive analysis including palaeocurrent direction,sandstone clastic composition,cutting combination,heavy mineral characteristics and grain size was made,combined with the study of outcrops surrounding the basin,the provenance and characteristics of parent rocks in the 8th member of Shihezi Formation in the southwest of Ordos Basin were deeply analyzed.The result shows that the south-western Ordos Basin can be divided into three provenances in the southwestern,southern and northern directions.The provenance of the south-western area is from the northern Qilian Mountains and the Western Qinling Mountain in the South-western Ordos Basin.The provenance of the southern area is from the northern Qinling Mountain.And the provenance of the northern area is the Yinshan Area in the north of the basin.