本区岩体位于西乡县之北、扬子准地台西北边缘、洋县一西乡一南郑早元古代晚期基性岩出露区的中部,第一期侵入的韵律性层状岩体。区内主要由下元古界变质岩及其中的基性、酸性岩组成结晶基底;其上不整合覆以震旦系及以后的未变质地层。下元古界在西乡地区出露较为完整, The rock mass is located in the north of Xixiang County, the northwestern margin of the Yangtze Platform, and the rhythmic stratiform rock invaded by the first phase in the middle of the late Early Early Proterozoic basement rock outcropping in Yangxian County. The area is mainly composed of the Lower Proterozoic metamorphic rocks and the basic and acidic rocks which form the crystalline basement; the unconformity covers the Sinian and the later unmetamorphic formations. Lower Proterozoic exposed in Xixiang more complete,