Abstract: The Hujiajian silver-gold area is located in the southern part of the Wuyuan-Wannian fault-fold zone with the NE-trending compressoshear faults as the leading structural elements.The NE-trending faults have experienced three stages of evolution:in the early stage, they behaved as sinistral compressoshear faults, accompanied by plastic-brittle deformationl in the middle stage, they turned into tensoshear faults characterized by dominantly brittle deformation;in the stage, dextral compressoshear movement occurred with associated plastic-brittle deformation.It is therefore considered by the author that the tectonic activities in the area were governed by NE-treading Cathaysian stress field in the early stage and by NNE-trending Neocathaysian stress field in the late stage, and that the NE-trending faults were produced by the compounding of the NE-trending Taishan-type structures with the Cathaysian structures.
The NE-trending fault zones are the major ore-controlling structures.Silver-gold mineralization in chiefly controlled by the north subzoue of the Hujiajian-Xialing fault zone.There occur silver-gold and tungsten-antimony mineralization in the south subzone.Tungsten mineralization is confined to the Kutian-Tangjiabian fault zone.In addition, the distribution, shape, size, and content of the ore bodies as well as their mineralization pattern and type are closely related to the NE-trending compressoshear faults.There is some synchronism between structural evolution and mineralization.