新疆东天山地区白山钼矿床的成因分析 |
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引用本文:屈文俊.2009.A genetic analysis of Baishan molybdenum deposit in East Tianshan area, Xinjia ng[J].Mineral Deposits,28(5):663~672 |
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基金项目: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)和安徽省优秀青年基金项目(08040106907) |
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中文摘要: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。 |
中文关键词:地质学 H、O同位素 Re-Os定年 成矿背景 白山钼矿床 东天山 |
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A genetic analysis of Baishan molybdenum deposit in East Tianshan area, Xinjia ng |
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Abstract: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. |
keywords:geology, H, O isotope, Re-Os isotopic dating, metallogenic background, Baishan molybdenum deposit, East Tianshan area |
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