摘要
造山型金矿形成于汇聚板块边缘,俯冲增生或碰撞造山体制,是现代矿床学研究的热点之一.西准噶尔地区有几十个造山型金矿,但其究竟形成在洋壳俯冲增生造山过程还是洋盆闭合后的碰撞造山过程,尚不清楚.本文系统总结了西准噶尔地区造山型金矿的时空分布及地质、地球化学特征,发现它们主要赋存于达拉布特断裂西北侧,可分为安齐(包括哈图金矿)和萨尔托海(包括萨Ⅰ金矿)两个成矿带;成矿作用受控于达拉布特走滑断裂引发的区域变质变形事件,矿体主要赋存于中晚石炭世变质火山沉积岩或蛇绿岩中,发育NaCl—H2 O—CO2±CH4±N2流体包裹体体系,成矿温度为170~380℃,成矿流体主要为变质热液,晚期为大气降水热液;成矿同位素年龄为271~300 Ma,已有资料显示西准噶尔地区存在多期次俯冲增生作用,并于晚石炭世—早二叠世消减完毕.而造山型金矿广泛发育的达拉布特西北侧古洋盆闭合于308~328 Ma,此后为大陆碰撞造山体制,因此西准噶尔造山型金矿形成于大陆碰撞造山体制,适合于碰撞造山成岩成矿和流体作用模式.晚石炭世—早二叠世,达拉布特地区陆—陆或弧陆碰撞过程中,大规模的韧脆性剪切变形及区域变质事件导致地层及围岩中不稳定组分发生变质活化,形成含矿变质流体,流体向上运移至韧—脆性转换带内形成了西准噶尔造山型金矿成矿系统.
Orogenic gold deposits were formed in the subduction-accretion or collision period on the convergent plate margin. Currently,it is one of the hottest topics in economic geology researches. Numbers of orogenic deposits have been discovered in the western Junggar,however,the geodynamic setting and timing of the deposits are poorly constrained. In this paper,we aim to figure out the evolution and mechanism of the mineralization,and provide constrains for the geodynamic settings. Located on the northwestern side of the Dalabute fault,the orogenic gold deposits in the western Junggar are hosted in the Carboniferous Metamorphic volcanic sedimentary rock or metamorphic ophiolite and controlled by the NW or/and EW-secondary faults that related to the Dalaubute fault event. The fluid inclusions are characterized by the presence of dominant CO2 and minor CH4 fluid,with metallogenic stages yield total homogenization temperatures of 170~380 ℃. The oxygen and hydrogen isotope compositions of water from fluid inclusions in quartz indicate that ore fluids comprised dominantly metamorphic water with a minor contribution of magmatic or meteoric water. Available isotopic ages of these mineralized systems cluster in Late Carboniferous to Early Permian(271~300 Ma),reflecting the metallogenic episodes that occurred during post-subduction collision regimes. The late Carboniferous to Early Permian geology of the Dalabute is interpreted as an collision zone developed between two arcs,which lead to the mineralization of the Anqi and Sartohay metallogenic belt.
作者
丁嘉鑫
韩申
黄柏诚
吴艳爽
张博
肖飞
王永
DING Jiaxin;HAN Shen;HUANG Bocheng;WU Yanshuang;ZHANG Bo;XIAO Fei;WANG Yong(School of Earth and Space Science,Peking University,Beijing,100871;Xinjiang Research Center for Mineral Resources,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi,Xinjiang,830011;Western Gold Karamay Hatu Gold Mining Co.,Ltd.,Karamay,Xinjiang,834000)
出处
《地质论评》
CAS
CSCD
北大核心
2019年第6期1439-1461,共23页
Geological Review
基金
国家自然科学基金资助项目(编号:U1803242及41602087)
国家深地资源计划项目课题(编号:2017YFC0601203)的成果~~
关键词
造山型金矿
流体
碰撞造山作用
西准噶尔
orogenic gold deposit
fluid
collisional orogeny
Western Junggar
