新疆乌拉根铅锌矿床地质特征与成因

新疆超大型远景规模的乌拉根铅锌矿床的发现是近年来我国有色金属矿地质勘查的重大进展之一。矿床位于塔西南凹陷北部,围岩为下白垩统克孜勒苏群厚层砂砾岩,上部盖层为古新世阿尔塔什组膏盐层,属砂岩容矿的铅锌矿床。矿体呈似层状分布于砂砾岩层的顶部,矿化带长度3km,厚度10～50m,最大厚度100m。矿体为灰白色砂砾岩的一部分,是紫色砂砾岩褪色蚀变矿化的结果。褪色蚀变带分布于克孜勒苏群顶部,东西长度超过140km,厚100～300m。矿体顶板直接围岩为角砾岩,是由膏盐层溶解坍塌形成的。矿石主要类型为砂砾岩型,砂砾成分与围岩砂砾岩一致,硫化物呈浸染状分布于胶结物中,少量块状矿呈脉状分布于走向断层中。主要硫化矿物为闪锌矿、方铅矿,含少量白铁矿,微量的黄铁矿、黄铜矿等;脉石矿物含量少,主要是方解石、白云石、少量绢云母、伊利石等。闪锌矿淡黄褐色,粒度细小,几乎全部呈胶状或环带状;方铅矿主要也呈微细粒状,少量颗粒见有环带,块状方铅矿矿石中方铅矿呈粗晶状。铅锌矿化与油气活动关系密切,矿石中广泛含有机质液泡。成矿作用与区域盆地卤水作用有关,形成于渐新世—中新世喜马拉雅运动早期,古地中海向西退却与塔里木盆地分隔时期。卤水中的金属物质与自膏盐层溶解并经生物还原提供的低价态硫的混合导致硫化物的沉淀。乌拉根铅锌矿床属于与盆地卤水作用有关的低温热液矿床。

The Geologic Characteristics and the Genesis of Wulagen Lead-zinc Deposit,Xinjiang, China

Wulagen lead-zinc deposit is located in the northern part of the southwest depression of Tarim basin,Wuchia County,Xinjiang.It is considered as a sandstone-hosted type deposit with the proved and prospective Pb-Zn reserves >10 Mt(Pb-Zn of 3.62%).The layered orebodies more than >3km long and 10~50m wide occur between the Lower Cretaceous Kizilsu Group(K1kz)of the red sandstone and the thick gyprocks of Paleocene Aertashi Formation.It's grey in color,mainly due to decolored alteration and mineralization of re...