| 内蒙古金厂沟梁金(铜)矿床的PGE、铁族和亲硫元素的地球化学特征与物质来源、形成环境 |
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| 引用本文： | 李怡欣,孙景贵,陈军强,门兰静,聂喜涛,张朋.内蒙古金厂沟梁金(铜)矿床的PGE、铁族和亲硫元素的地球化学特征与物质来源、形成环境[J].地学前缘,2010,17(2):336. |
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| 作者姓名： | 李怡欣 孙景贵 陈军强 门兰静 聂喜涛 张朋 |
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| 作者单位： | 1. 吉林大学,地球科学学院,吉林,长春,130061
2. 天津地质矿产研究所,天津,300170 |
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| 基金项目： | 国家自然科学基金，中国科学院地质与地球物理所开放课题，内蒙古金陶股份有限公司资助项目 |
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| 摘 要： | 首次采用盐酸-过氧化氢封闭熔矿与ICP-MS相结合的方法,对金厂沟梁金(铜)矿床东、西两矿区典型矿石的铂族元素(PGE)、亲铁以及亲硫元素的含量进行了系统测定,结果显示矿石中上述元素的含量均高于实验的检测限;地球化学演化特征显示含矿流体具有岩浆性质,PGE对原始地幔/球粒陨石标准化后的配分曲线均呈强烈左倾斜的分馏模式,其配分曲线和与幔源岩浆有关的富铜硫化物和富铜镍硫化物熔体的形式相似,并与幔源玄武岩、碳酸盐熔体的配分模式基本一致,反映含矿流体具有幔源岩浆属性;从区域构造、岩浆热事件角度出发,结合典型斑岩铜(钼)矿床的PGE特征,初步确定其含矿流体形成于中生代大陆边缘环境,其直接的热动源是中生代底侵的玄武岩浆。成矿阶段富含金、铜矿石的Pd/Pt、Pd/Ir比值接近低钛玄武岩浆以及玄武安山岩,而成矿早阶段贫金、铜样品的Pd/Pt、Pd/Ir比值接近地幔;反映早期含矿流体可能是直接来自中生代幔源玄武质岩浆结晶分异,而富金(铜)流体的形成可能是玄武质岩浆演化晚期被地壳物质强烈混染后的富超临界流体岩浆(低钛熔体)发生岩浆与流体分离而产生;含矿流体演化过程的PGE地球化学行为与Cu或S(As)的饱和度有关,即主要受亲硫(铜)元素或结晶分异的硫化物矿物相所制约。
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| 关 键 词： | 地球化学 铂族-铁族-亲铜元素 金(铜)矿床 金厂沟梁 内蒙 |
The geochemical characteristics of PGE,siderophile- and chalcophile elements of Jinchanggouliang gold (copper) deposits, Inner Mongolia, their provenance and ore-forming tectonic setting |
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| Li Yixin,Sun Jinggui,Chen Junqiang,Men Lanjing,Nie Xitao,Zhang Peng.The geochemical characteristics of PGE,siderophile- and chalcophile elements of Jinchanggouliang gold (copper) deposits, Inner Mongolia, their provenance and ore-forming tectonic setting[J].Earth Science Frontiers,2010,17(2):336. |
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| Authors: | Li Yixin Sun Jinggui Chen Junqiang Men Lanjing Nie Xitao Zhang Peng |
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| Abstract: | In this study, we provide a novel method which combines the technique of ore-melting blocked by HCl(aq) and H_2O_2 with the ICP-MS for the first time to determine the amount of Platinum metal group elements (PGE), siderophile elements and chalcophile elements in the typical ore in the East and West ore fields of Jinchanggouliang gold (copper) deposits. The experimental results show that the content of these elements in the ore is higher than the detection limit of the test technique, especially for the PGE. The geochemical evolution characteristics of these elements indicate the ore-bearing fluid having the magma properties. The characteristics of PGE prove the fact that the primitive mantle-normalized PGE shows a strong left-inclined fractional patterns, which is similar to the copper-rich sulphide melt and nickel-sulphide melt associated with mantle-derived magma, and to the mantle-derived basalt and carbonate melts, so we suggest that the ore-bearing fluid has the properties of mantle magma fluid. Considering the regional structural, magmatic and thermal events, and combined with the geochemical characteristics of reported typical porphyry copper (molybdenum) deposits, we may draw the conclusion that the ore-bearing fluid formed in the Mesozoic continental marginal environment, and the thermal dynamic source may have been derived from the underplating basaltic magma. The Pd/Pt and Pd/Ir ratios of Au and Cu-rich ore samples are close to those of low-titanium basalt and basaltic andesite for the ore-forming stage, but the ratios of the Au and Cu-poor samples are close to those of the mantle end-member for the early mineralization stage, which indicates the early ore-bearing fluid may directly come from the differentiation and crystallization of Mesozoic basalt magma, while the Au and Cu-rich fluid may have been produced by the separation of the fluid from the supercritical fluid-rich magma (low Ti magma), which was formed in the later evolution stage of basalt magma with contamination by crustal materials. The PGE geochemical activity in the ore-bearing fluid evolution process was related to the saturation of copper or sulfur (arsenic), that is, it was controlled by chalcophile elements or crystallized mineral facies of sulfides. |
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| Keywords: | geochemistry PGE siderophile- and chalcophile elements gold(copper) deposits Jinchanggouliang Inner Mongolia |
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