新疆西天山伊尔曼德金矿矿床地质及成矿机理初步研究

Study on Geology and Metallogenic Mechanism of Yelmand Gold Deposit in West Tianshan, Xinjiang

伊尔曼德金矿位于吐拉苏盆地奥陶系灰岩与中上泥盆统火山-沉积岩间的不整合面,赋矿围岩为蚀变凝灰岩、岩屑凝灰岩和凝灰质砂岩,矿石为热液角砾岩。矿石角砾成分复杂,胶结物为石英、黄铁矿和白铁矿。据矿石中脉体的切穿关系,将成矿作用划分为:硅化、黄铁矿化和绢云母化阶段(I);角砾化、硅化、黄铁矿-白铁矿阶段(II)及重晶石-方解石阶段(III)。两期流体作用叠加形成高级泥化带的过程对应着金矿成矿过程。在研究伊尔曼德金矿成矿作用的基础上,建立新的成矿模式。

Yelmand gold deposit locates in Tulasu volcanic-sedimentary basin.The orebody lies on the unconformity between the basement and Middle-Late Devonian volcanic-sedimentary strata. The wall-rocks are tuff, lithic tuff and tuffaceous sandstone.The orebody consists of hydrothermal breccias which were cemented by quartz and sulfides. Fluid evolu- tion can be divided into three stages：silicification,pyritization and sericitization （stage I）;brecciation,silicification,and crystallization of pyrite and marcasite （II）;crystallization of barite and calcite （III）.The advanced argillization resulted from the combination of two-stage fluid,and this process plays a primary role in the formation of gold deposit.We established a metallogenic model for the Yelmand gold deposit based on previous studies and our new data.