鄂尔多斯盆地东南部延长探区上古生界物源分析

Provenance analysis of Upper Paleozoic in Yanchang Blocks,the Southeast Ordos Basin

为查明鄂尔多斯盆地延长探区上古生界的物源方向及物源分区,揭示该地区沉积体系的分布格局,应用碎屑组分、重矿物、稀土元素分析等多种研究方法,在对物源区构造演化背景分析的基础上,对延长探区上古生界各层段的物源特征及影响范围进行了系统研究。结果表明,研究区主要受到北、南两个方向的物源控制,其中北部物源是控制区内沉积的最主要物源,南北物源大致在甘泉—富县—宜川一带交汇。本溪组至山西组山23沉积期,南部物源并未影响到研究区;从山22沉积期始,南部物源开始影响研究区,至石盒子—石千峰期,南部物源的影响逐渐增大,成为研究区主要的物源之一。

To determine the sedimentary source and division of Upper Paleozoic in Yanchang Blocks of Ordos Basin, and prove the sedimentary distribution pattern in the target area, through the abundant analysis test da- ta such as detrital minerals, heavy minerals and rare-earth elements, and based on the study of provenance tectonic evolution, the sedimentary source and division of the sub members of Upper Paleozoic in Yanchang Blocks are analyzed systematically. The results indicate that two source directions can be recognized： north and south, and the north direction is the main one controlling the sediments. The sediments coming from the two directions converge in the area of Ganquan-Fuxian-Yichuan. It was not until the period of Shan22 did the south sedimentary source begin to have an influence on Yanchang Blocks. The influence of the south sedimen- tary source grew with time, and it became one of the main sources till the period of Shihezi and Shiqianfeng.