The wuchuan county locating the ecological vulnerable region of northern foot of yin mountain was studied and divided by the principal components cluster into the four ecological economical regions of returning farmland to forest land , southeast mountain agricultural region , north hillside agricultural region , northwest wind erosion and sandy region of joining agriculture and herbage , and southwest region of joining agriculture and herbage 本文以位于阴山北麓生态脆弱带的武川县为研究对象，通过主成份聚类分析将武川县划分为东南部山地农业区、北部丘陵农业区、西北部风蚀沙化农牧结合区和西南部山地农牧结合区等四个退耕还林生态经济类型区。
Based on the variation of light / heavy mineral components of sedimentary rocks , the typomorphic characteristics of various debris , the cathodoluminescence color of quartzes , the direction of paleocurrent and the extension of sedimentary facies , two source direction of the studied area in carboniferous and permian can be recognized , one is in bayanwusu , wulan ' ge ' er and hetaoyinshan area north of hangjinqi in the north margin of ordos , another is alashan area in the northwest margin of ordos 在深入研究本区沉积岩轻、重矿物组分的变化、各种岩屑的标型特征、石英阴极发光颜色、古水流方向及沉积相带展布等基础上，认为研究区石炭?二叠纪的物源方向主要有两个，分别为：北缘杭锦旗以北的巴彦乌苏、乌兰格尔及河套阴山地区；以及研究区西北缘的阿拉善地区。
