西秦岭地球物理场的地质解释

西秦岭及邻区，由区域重力异常反映的地壳深部构造和剩余重力异常反映的区域地质构造呈明显的立体交叉。以通渭—武都近南北向重力梯级带反映的隐伏深断裂是划分东、西秦岭和祁连、北秦岭构造单元的分界，亦是秦岭复合型造山带向西拓展为祁连、西秦岭和松潘—甘孜各造山带的转折枢纽。西秦岭北缘断裂带在不同地质历史阶段，其边界位置、断裂性质不同，深部产状和浅部产状不同，因此伴随Ａ型俯冲形成大陆碰撞型花岗岩，并出现岩体磁性分带现象。

EXPLANATION OF THE GEOPHYSICAL FIELD OF THE WEST QINLING

The crustal deep seated structure reflcted regiona gravity anomalous,and the regional geological structure reflected residual gravity anomalous appeared obvious grade separation in the west Qinling and its adjacent areas.Buried profound fault reflected the gravity stepped zone on N S direction naerly at Tongwei Wudu is a demarcation line diveded into the east Qinling,the west Qinling,Qilian and the north Qinling structure units,and is hinge of Qilian,the west Qinling and Songpan Ganzi orogenic belts.The hinge hed been developed toward the west by Qinling compound type orogenic belt.The northern margial fault zone at the west Qinling during geological historical stages was not alike at its border positions,fault features,deep seated structures and shallow structures.For this reason,following A type subduction the continental collision type granite had been formed,magntic zonality phenomenon of rock bodies had been showed elso.