阿舍勒铜锌块状硫化物矿床地质特征和成因

GEOLOGICAL CHARACTERISTICS AND GENESIS OF THE ASHELE COPPER ZINC MASSIVE SULFIDE DEPOSIT,XINJIANG

阿舍勒矿床与早—中泥盆世双峰式火山活动有着成因联系，产于火山洼地中，它在喷气－沉积阶段形成，后又经历了变质改造和岩浆热液叠加。矿床具有双层结构、很好的矿化分带和蚀变分带。成矿流体的温度、压力和酸碱度等物理化学条件变化引起了围岩蚀变和矿石堆积，在海底界面上下形成了具有成因联系的两套矿化。成矿物质既来自深循环的海水，也来自岩浆热液。

The Ashele massive sulfide deposit occurs in the Ashele Devonian volcano sedimentary basin lying on the southern margin of Altay orogenic belt.The basin was formed as a result of rift evolution on the basis of Proterozoic Early Paleozoic continental crust,and experienced deformation of regional nappe structure.Mineralization took place at the interval between Early Middle Devonian volcanic activities of the bimodal spilite keratophyre volcanic suite.The deposit has two layer structure:a massive sulfide orebody in the upper part and a disseminated sulfide orebody in the lower part.In the massive sulfide orebody there exists vertical zonation of S→Cu,S→Cu,Zn,S→Cu,Pb,Zn→Cu,Zn,Pb,BaSO 4 which is a reflection of ore accumulation sequence at the bottom of the sea.Around the disseminated sulfide orebody are well developed wall rock alterations,which exhibit from the inside outward the zonation of sericite quartz metasomatite→chlorite sericite metasomatite→weakly hydrolytic pyroclastic rocks,suggesting characteristics of acid leaching.Studies of ore deposit geology,temperature pressture geochemistry and stable isotope geochemistry indicate that the ore forming fluids were composed of deeply circulating sea water and magmatic water,and that the ore forming materials were derived from the lower crust.In addition,the ore forming process has been discussed and a metallogenic model of mixed fluids comprising deeply circulating sea water and magmatic water has been established.