新疆东天山地区白山钼矿床的成因分析  

A genetic analysis of Baishan molybdenum deposit in East Tianshan area, Xinjiang

作　　者：张达玉[1] 周涛发[1,2] 袁峰[1,2] 范裕[1] 刘帅[1] 屈文俊[3] 

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009 [2]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074 [3]国家地质实验测试中心,北京100037

出　　处：《矿床地质》2009年第5期663-672,共10页Mineral Deposits

基　　金：国家重点基础研究发展规划项目(2007CB411304;2001CB409800);国家自然科学基金项目(40772057);安徽省优秀青年基金项目(08040106907)共同资助

摘　　要：白山钼矿床位于东天山觉罗塔格构造带的东部,赋矿围岩为下石炭统干墩组的黑云母长英质角岩,矿化石英网脉发育。文章测得含矿石英脉中的石英流体包裹体δ18OSMOW值为9.1‰~10.0‰,平均9.425‰,与石英相平衡的水δ18OH2O值为3.357‰~4.257‰,平均为3.682‰;δDSMOW值为-105‰^-69%,平均-89.25‰。氢氧同位素组成显示白山钼矿床的成矿流体是岩浆水与发生了水-岩作用的大气降水的混合热液,含矿流体以岩浆水为主,演化大气降水的加入是成矿物质沉淀的重要因素。测得辉钼矿的Re-Os等时线年龄为(227.7±4.3)Ma(MSWD=0.32),指示白山钼矿床形成于中三叠世。矿床地质特征和地球化学特征指示白山钼矿床是斑岩型矿床,推测成矿物质主要来自于矿体下部的矿化花岗(斑)岩体。此外,作者还探讨了白山钼矿床的成矿背景,认为矿床形成于挤压的构造环境,是受到同时代古特提斯洋闭合的陆内远程效应影响而产生的成岩成矿作用。The Baishan molybdenum deposit is located in the eastern Jueluotag tectonic belt of the East Tianshan Mountains. The wall rocks are biotite-felsic hornstone with well-developed mineralized quartz veins, belonging to Lower Carboniferous Gandun Formation （C1g）. The H, O compositions of the hydrothermal fluids in the quartz veins are as follows： δ18OSMOW values are 9.1‰～10.0‰ with an average of 9.425‰, δ18OH2O balanced with quartz are 3.357‰ ～4.257‰ with an average of 3.682‰, and δDSMOW are -105‰～ -69%, with an average of -89.25‰. Characteristics of H, O isotopes indicate that the ore-forming hydrothermal fluid was dominated by magmatic water with the participation of some evolutionary meteoric water that had experienced the water-rock interaction. The magmatic water supplied the main metallogenic materials, and the evolutionary meteoric water served as an important factor for the precipitation of the metallogenic materials. The Re-Os isochronal age of molybdenites is （227.7±4.3） Ma（MSWD=0.32）, suggesting that the mineralization of the ore deposit took place in Middle Triassic. These geological and geochemical characteristics imply that the Baishan Mo deposit is a porphyry deposit, and its metallogenic materials mainly came from deep granitic rock. This paper deals with metallogenic background, and the authors hold that the Baishan molybdenum deposit was formed in a compression environment after the post-collisional stage, and its mineralization was controlled by the distant effect of the Paleo-Tethys Ocean in Triassic. This paper has supplied a solid foundation for further researches on mineralization of granitoids which intruded into the same tectonic background in Jueluotag block as well as in East Tianshan area.

关 键 词：地质学 H、O同位素 RE-OS定年 成矿背景 白山钼矿床 东天山 

分 类 号：P618.65[天文地球—矿床学]