萨瓦亚尔顿金矿床成矿地质特征及同位素组成

西南天山的萨瓦亚尔顿金矿床，赋存于中-上石炭统浊积岩系中.矿化受构造破碎带控制，以含矿的石英细（网）脉和含矿的石英-碳酸盐细（网）脉形式产出.矿体呈似层状和透镜状，矿石的矿物组成和矿石类型复杂，矿石中金与黄铁矿、毒砂、黄铜矿等硫化物密切共生，金矿物以银金矿为主.铅、硅、硫同位素组成表明，成矿物质主要来自深部较老的地层和岩石.氢、氧、碳同位素特征显示，成矿作用乃通过大气降水补给的地下水渗入深部，经加热循环并溶滤围岩中的矿质，迁移到减压空间和有利岩性层中而成矿.成矿时代属燕山中-晚期.

METALLOGENIC CHARACTERISTICS AND ISOTOPIC COMPOSITION OF SAWAYARDUN GOLD DEPOSIT,XINJIANG

The Sawayardun gold deposit,located in the west of Xinjiang,is one of the most important gold deposits found in China in the recent years.The deposit occurs in the Middle Upper Carboniferous turbidite sequence,and the mimeralization is restricted to the fracture zones developed in the sequence.With layered or lensoid morphology,the orebodies extend in NE trend,consistent with the extension of the fracture zones.The ore is composed of gold bearing quartz and quartz siderite stringer stockwork with disseminated metal sulfides.The gold in the ore is characterized by microtexture and low fineness and associated with pyrite,arsenopyrite,and chalcopyrite.The lead compositions obtained from the ore are as follows:206Pb/204Pb ranging from 18.645 to 18.382;207Pb/204Pb from 15.470 to 15.659;208Pb/204Pb from 38.752 to 38.062.The δ34S values of the metal sulfides analyzed range between +2.61‰ and -1.02‰. The δD values from quartz and siderite vary from -42.5‰ to -72.2‰; the δ18O,from +2.94‰ to -11.57‰;and the δ13Cco2,from -2.35‰ to -10.50‰.The mineralization dates between 167±18 and 98±9 Ma by K Ar method.Based on the characteristics of the isotopic composition,it is suggested that the Sawayardun deposit was developed during the late Yanshan movement,and the host and underlying strata supplied the source for the mineralization.It could formulate a model of circulating meteoric water becoming a heated hydrothermal fluid in the depth,dissolving gold and other metals from the country rocks through which it traversed,and carrying them up to the pressure reduced environment — the fracture zones,where they were precipitated because of the boiling derived from the pressure reduction.