江西虎家尖银金矿区构造特征与矿化研究

GEOLOGICAL STRUCTURES AND THEIR CONTROL OF SILVER-GOLD ORES IN HUJIAJIAN AREA,JIANGXI

虎家尖银金矿区位于华夏系婺源—万年断褶带的南段，以ＮＥ向压扭性断裂带为主要构造型式。ＮＥ向压扭性断裂的成生演化，大体经历了３个阶段：早期为左行压扭活动阶段，主要表现为塑—脆性形变；中期阶段以张扭性的脆性形变为主；晚期则显示出右行压扭的塑—脆性形变特征。笔者认为，矿区构造活动早期受华夏系应力场的控制，晚期受新华夏系应力场的制约，并认为矿区ＮＥ向断裂是新华夏系泰山式构造与华夏系构造复合的产物。ＮＥ向断裂带也是矿区最重要的成矿控矿构造，其中虎家尖—峡岭（水库）断裂带北亚带控制矿区主要的银、金矿化带，南亚带则以银金和钨锑矿化为主；而库田—唐家边断裂带主要控制钨矿化．此外，矿体的分布、形态、规模、富集程度、矿化形式及矿化类型，均与ＮＥ向压扭性断裂的形变阶段有关，显示构造演化与成矿作用的同步性。

he 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.