SHEAR VEIN SYSTEM IN JIAPIGOU GOLD BELT OF EASTERN SEGMENT OF NORTHERN MARGIN OF NORTH CHINA BLOCK

The auriferous veins occurring in the Jiapigou Gold Belt are almost within shear zones of varied orientations and scales.Our study indicates that the regional NS-trending major shear zone had experienced a long-term right-lateral shearing,which resulted in the formation and progressive straining of the secondary shear folding and vein systems along the major shear zone.It is suggested that regional right-lateral shearing controls the general shapes and orientations of the veins,and progressive straining controls their internal structural details of vein systems.Based on these criterions,different vein types,such as R,R',D,T defined by Riedel shear shstem,could be identified within in the Jiapigou shear zone,which may have practical usefulness in mineral prediction and exploration.