北京西山水峪复合型旋扭构造研究

NOTE ON SHUIYU COMPOUNDING VORTEX STRUCTURE IN WEST MOUNTAINS,BEIJING

以北京西山水峪为中心有３条弧形断裂，总体呈涡轮状，且都具有压扭性特征，外旋呈逆时针扭动。组成这个旋扭构造的结构面产状不规则，力学性质较复杂，不易辩认。通过构造复合系统分析，查明该旋扭构造的旋回面大都是追踪早期不同系统、不同性质结构面归并复合的结果，为燕山期新华夏系ＳＮ向对扭构造应力场的派生产物。

There are three arcuate faults that surround Shuiyu in the form of a turbine in the West Mountains,Beijing,forming a vortex structure. These faults are characteristic of compresso-shear structural planes,and their arrangement indicates a counterclockwise rotation of the outer side relative to the inner side of the structure. By an analysis of the compounding relation of the structural elemonts present in the area,we find that the vortical surfaces of the vortex structure were produced by trailing the preexisting structural planes of other systems. So we come to the conclusion that it was derived from a N-S shearing responsible for the Neocathaysian structural system during the Yanshanian movement.