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文摘
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安徽繁昌地区作为长江中下游Fe、Cu、Au成矿带中的重要矿集区,发育一系列以桃冲铁矿为代表的磁铁矿型铁矿床。对桃冲矿区分布的岩浆岩、围岩与赋矿矽卡岩的稀土元素地球化学特征对比,表明三者稀土含量及其配分模式存在差异,桃冲铁矿夕卡岩稀土总量较低,轻稀土富集重稀土亏损,呈右倾过渡型配分模式,具明显Eu正异常。通过对桃冲铁矿床内包裹体的岩相学、显微测温、激光拉曼光谱探针分析,桃冲铁矿体中发育有熔融包裹体、气液相包裹体、含子晶多相包裹体、纯液相包裹体4种类型。成矿流体具中高温、高盐度、富水特征,富含Na~+、Ca~(2+)、Mg~(2+)、K~+、Cl~-、SO_4~(2-)离子。结合透岩浆流体成矿理论探讨成矿流体及演化,认为形成铁矿床的物质来源为深部富铁夕卡岩矿浆,侵位过程中受构造环境影响,因温压条件的迅速改变含矿流体与夕卡岩浆发生解耦作用,于构造薄弱部位贯入形成矿体。 |
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其他语种文摘
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The Fanchang District as an important metallogenic cluster district in the Fe-Cu-Au polymetallic metallogenetic belt along the Middle-Lower Yangtze Reaches,develops a series of magnetite deposits represented by Taochong iron deposit.Comparing the REE geochemical characteristics of the magmatic rock,wall rock and ore-bearing skarn in Taochong ore zone,the content and the distribution patterns of REE are significantly different.The skarn has a pattern of LREE enrichment and HREE depletion transitional right-dipping pattern with a positive Eu anomaly.Four types of fluid inclusion: melt inclusion,liquid-gas two-phase inclusion,daughter-minerals bearing polyphase inclusion and liquid phase inclusion,have been found in minerals from Taochong iron deposit on the basis of the petrography,microthermometry and Raman spectrum analyses.Ore-forming fluids are medium-high temperature,high salinity,water-rich,and rich in Na~+,Ca~(2+),Mg~(2+),K~+,Cl,SO_4~(2-).Ore-forming fluid features and developments are discussed combining with the theory of transmagmatic fluids.It is considered that the origin of iron deposit is Fe-rich skarn ore-magma from the depth.The decoupling of ore-forming fluid and skarn took place in the process of emplacement.The deposit was formed by injection in the weak tectonic belt caused by structural processes. |
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来源
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地学前缘
,2012,19(4):82-95 【核心库】
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关键词
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夕卡岩
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矿床成因
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透岩浆作用
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桃冲铁矿
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长江中下游成矿带
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地址
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1.
西安地质矿产研究所, 陕西, 西安, 710054
2.
中国科学院广州地球化学研究所, 广东, 广州, 510640
3.
中南大学地球科学与信息物理学院, 有色金属成矿预测教育部重点实验室, 湖南, 长沙, 410083
4.
华东冶金地质勘查研究院, 安徽, 合肥, 230088
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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1005-2321 |
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学科
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地质学 |
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基金
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中国科学院知识创新工程重要方向项目
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安徽省公益性地质工作项目
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文献收藏号
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CSCD:4576880
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