山东沂南金铜铁矿床同位素地球化学研究 |
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引用本文:LI Ke,GU XueXiang,DONG ShuYi.2009.Isotopic geochemistry of Yinan Au_Cu_Fe deposit in Shandong Province[J].Mineral Deposits,28(1):93~103 |
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基金项目:国家自然科学基金(40772060)、中国地质调查局危机矿山接替资源找矿项目(200637035)、高等学校学科创新引智计划(B07011)、中国地质大学地质过程与矿产资源国家重点实验室基金(GPMR0531) |
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中文摘要:山东沂南矽卡岩_热液型金铜铁矿床位于沂沭断裂带西侧,矿床受控于 燕山期中酸性杂岩体与围岩的接触带及围岩中的构造薄弱带(不整合面、层间破碎带、滑脱 带),矿体围绕岩体呈环带状产出。文章在成矿地质条件分析基础上,系统研究了沂南金矿 床的氢、氧、碳、硫、铅同位素以及钕锶同位素的组成特征,探讨了成矿热液类型和成岩成 矿物质来源。研 究表明,成矿热液早期以岩浆热液为主,后期有部分大气降水的加入,且两者均与围岩发生 了同位素交换作用;热液中碳主要为深源岩浆来源,少量来自海相碳酸盐岩的溶解作用;硫 化物矿石中的硫同位素组成特征反映了硫源具有深源岩浆硫的特征;铅主要为放射性成因的 “J型铅”,其源区年龄(2.37 Ga)暗示了矿床的成矿物质来源于结晶基底(新太古代泰山 群);铷锶同位素组成特征表明,含矿中酸性岩体的成岩物质来源为幔壳混合型。 |
中文关键词:地球化学 矽卡岩_热液型金铜铁矿床 同位素 中酸性杂岩体 中生 代 鲁西 |
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Isotopic geochemistry of Yinan Au_Cu_Fe deposit in Shandong Province |
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Abstract:The Yinan Au-Cu-Fe deposit located west of the Yishu deep fault zone in western Shandong Province is a skarn and hydrothermal type ore deposit. The ore bodies occur in the contact zones between the Yanshanian intermediate-acidic composite intrusions and their surrounding wall rocks. Based on metallogenic settings, this paper has analyzed the composition characteristics of H, O, C, S, Pb and Rb-Sr isotopes and the indicative meaning of these isotopes to chemistry of the ore fluids and the sources of the ore-forming materials and intrusions. The composition of H and O isotopes shows that ore fluids were most likely composed of magmatic water mixed with limited meteoric water at the late ore-forming stage. Sulfur and carbon isotopic data suggest that the ore-forming materials were mainly d erived from the deep magma and subordinately from the dissolution of wall rocks. The significant Pb isotopic values of the ore might have resulted from the interfusion with a large amount of radioactive anomalous Pb (“J" type Pb), whose calculated age (2.37 Ga) implies that the ore-forming materials had close genetic relations with the crystalline basement (Taishan Group). It can be deduced from the composition of Rb-Sr isotopes that the ore-forming stocks might have been the remelting products of high-maturity crustal materials or have resulted from the mixture of crustal materials with limited mantle components. |
keywords:geochemistry,skarn and hydrothermal type Au_Cu_Fe deposit, isotope, intermediate_acidic composite intrusions, Mesozoic, western Shandong |
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