NOTE ON SHUIYU COMPOUNDING VORTEX STRUCTURE IN WEST MOUNTAINS, BEIJING

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.