鄂尔多斯盆地上石炭统—中二叠统砂岩物源分析*

对区域地质、地层接触关系、砂岩组分、重矿物及微量元素等的综合分析与研究结果表明，鄂尔多斯盆地北部上石炭统—中二叠统砂岩的物源区主要为再旋回造山带物源区，并可划分出乌海—银川、杭锦旗—东胜及准格尔旗—府谷3个物源区。受物源分异的影响，盆地内部石英砂岩分布以杭锦旗—东胜为界，具有明显的东西分区性。其中石英砂岩主要分布于盆地西部，古水流、重矿物及砂岩组分指示物源来自阿拉善古陆。而盆地东部总体上是岩屑砂岩的覆盖区，物源主要来自盆地北部和东北部阴山地区。盆地西南部及南部砂岩的物源区为克拉通地块和再旋回造山区，物源区与秦祁造山带的演化关系密切，具有稳定与活动的双重特性，可划分出海原、同心—中宁，平凉—固原、环县及耀县—宜君、富县3个主要物源区。南北物源汇水区在环县—富县—乡宁一带，呈北西西向狭长带状延伸，并从山西期—盒8期呈逐渐南移趋势。盆地西部物源到下石盒子组沉积时期才提供粗碎屑物质补给，以含有较多的长石石英砂岩为特征。周至柳叶河石炭—二叠系砂岩的物源区为再旋回造山带物源区和陆块物源区，为北秦岭造山带内山间盆地，属于盆地外缘，并与鄂尔多斯盆地呈连续过渡的关系。

Provenance analysis of sandstone of the Upper Carboniferous to Middle Permian in Ordos Basin

Based on comprehensive study of regional geology,stratigraphic contact relations,sandstone fragment components,heavy mineral and trace elements,the Upper Carboniferous to Middle Permian provenance area for the north Ordos Basin mainly come from recycling orogeny area,and can be divided into three provenance areas that are Wuhai-Yinchuan,Hangjinqi-Dongsheng,Zhungeer-Fugu.But affected by variation provenance and bounded by Hangjinqi-Dongsheng,the distribution of quartz sandstone of Ordos Basin that was derive...