Features and significance of the Yudai porphyry copper deposit in the Kalatag district,eastern Tianshan,NW China

1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et al.,2006).The Dannanhu belt in eastern part of the area is interpreted as a volcanic arc and forms an important mineralized zone bordered by the Turpan-Hami Basin to the north and Kanggur back-arc basin to the south.

东天山卡拉塔格地区玉带铜矿床地质特征及成因

玉带铜矿床位于东天山大南湖—头苏泉岛弧带北缘的卡拉塔格地区,为近年来发现的中型铜矿床。通过野外地质调查和室内研究,对该矿床地质特征及成因进行探讨,发现矿床含矿地质建造为一套火山岩—火山碎屑岩,成矿地质体为石英闪长玢岩,矿体产于石英闪长玢岩体及其与围岩接触带,受断裂控制,主要呈脉状和透镜状。矿石类型以浸染状和细脉状为主,矿石组构以粒状结构,浸染状和细脉状构造为主,金属矿物主要为黄铜矿和黄铁矿,脉石矿物主要为石英,其次为绿泥石和绢云母。成矿过程可划分为石英—磁铁矿、钾长石—石英—黄铁矿、石英—黄铁矿—黄铜矿—辉钼矿和石英—碳酸盐—石膏4个阶段。矿区普遍发育钾化、硅化、绿泥石化、绿帘石化、绢云母化和碳酸盐化等蚀变,具带状分布特征,水平方向上由石英闪长玢岩中心向外可划分为钾化—硅化带、硅化—绢云母化带、泥化带和绿泥石—绿帘石化—碳酸盐化带;垂向上由石英闪长玢岩中心向外可划分为钾化—硅化带、硅化—绢云母化—黄铁矿化带和绿泥石—绿帘石化—碳酸盐化带。玉带铜矿床的成矿地质条件、矿体特征及围岩蚀变特征均与大南湖—头苏泉岛弧带斑岩型矿床一致,属于斑岩型铜矿床。