西天山卡特巴阿苏金铜矿床围岩蚀变特征及地质意义

Characteristics of Wall Rock Alteration and Geological Significance in Kateba'asu Au-Cu Deposit,Western Tianshan Mountains,Xinjiang

卡特巴阿苏金铜矿床位于新疆那拉提中天山构造带北缘,是近年来发现的首个特大型金铜矿床。矿体受二长花岗岩体内断层破碎带-节理构造系统及二长花岗岩、闪长质岩脉与大理岩捕掳体接触带的控制。矿区存在2类蚀变:①在二长花岗岩内,从破碎带中心向两侧依次为钾化、硅化-绢云母化、绿泥石化、高岭土化的蚀变;②二长花岗岩体、闪长质岩脉与大理岩捕掳体内、外接触带的矽卡岩化,蚀变矿物主要为石榴石、辉石、角闪石、绿帘石等,具明显分带特征。矽卡岩矿物的电子探针分析结果显示为钙矽卡岩。金矿体、金铜矿体在空间上不完全重叠,结合矿石、矽卡岩结构构造特征,认为本区存在2期成矿作用,分别与二长花岗岩和闪长岩脉岩浆期后热液作用有关,早期以金矿化为主,晚期以金铜矿化为主,且矿化局部叠加于早期矿体之上。矿床类型为矽卡岩-破碎带蚀变岩复合型金铜矿床。

The Au-Cu deposit of Kateba＇asu located in the north of nalati middle Tianshan tectonic belt was the first dis- covered superlarge Au-Cu deposit in nalati tectonic belt in recent years in Western Tianshan Mountains.Ore bodies are mainly controlled by the adamellite shattered fault zone-joint structural system and contace zone of adamellite,dioritic dykes with marble xenolith.The mining have 2 types of alteration： one is within the adamellite, from the center of shat-tered fault zone to the sides are potassium,silicification-sericitization,chloritization,kaolinization,etc;another is skarnization in adamellite,dioritic dykes and marble xenoliths endocontact and exocontact zone,altered minerals are gamet,pyrox- ene,hornblende,epidote,etc,with obvious zoning features.The research on the skarn mineralogy by electron microprobe analysis shows that belongs to the calcium skarn.The gold ore body and gold copper ore bodies are not completely over- lapped in space.The structure characteristics of ore and skarn are displayed that the mine has two mineralization,respec- tively related to adamellite and dioritic dykes,early stage is all about gold mineralization,and later stage is gold and cop- per mineralization,and later ore bodies superimpose on earlier orebody.The deposit belong to the type of skarn-fracture zone alteration rock and compound superposition Au-Cu deposit.