| 相山铀矿田成矿流体特征:来自微量、稀土元素地球化学证据 |
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| 引用本文： | 刘斌,陈卫锋,方启春,毛玉锋,唐湘生,严永杰,魏星,凌洪飞.相山铀矿田成矿流体特征:来自微量、稀土元素地球化学证据[J].岩石学报,2019,35(9):2774-2786. |
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| 作者姓名： | 刘斌 陈卫锋 方启春 毛玉锋 唐湘生 严永杰 魏星 凌洪飞 |
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| 作者单位： | 内生金属矿床成矿机制研究国家重点实验室, 南京大学地球科学与工程学院, 南京 210023,内生金属矿床成矿机制研究国家重点实验室, 南京大学地球科学与工程学院, 南京 210023,核工业二七〇研究所, 南昌 330200,核工业二七〇研究所, 南昌 330200,核工业二七〇研究所, 南昌 330200,核工业二七〇研究所, 南昌 330200,核工业二七〇研究所, 南昌 330200,内生金属矿床成矿机制研究国家重点实验室, 南京大学地球科学与工程学院, 南京 210023 |
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| 基金项目： | 本文受国家重点研发计划专项（2017YFC0602601）和中国铀业有限公司"高校铀矿地质科研项目"联合资助. |
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| 摘 要： | 相山铀矿田的成矿流体性质和来源存在争议,为进一步探讨相山铀矿田成矿流体的性质和来源,本文对相山铀矿田西部的居隆庵铀矿床和北部的沙洲铀矿床中的新鲜围岩、蚀变围岩及矿石的微量、稀土元素含量及其变化进行了研究。结果显示:在含较多热液成因萤石的居隆庵铀矿床中,从新鲜围岩到蚀变围岩到矿石,Zr、Hf含量先降低再升高;而在含少量热液萤石的沙洲铀矿床中,新鲜围岩、蚀变围岩和矿石的Zr、Hf含量基本一致。鉴于富F流体易汲取岩石中的Zr、Hf,因此,这两个矿床中不同类型样品Zr、Hf含量的不同变化趋势,可能与居隆庵铀矿床的成矿流体富F、而沙洲铀矿床的成矿流体相对贫F有关。这两个铀矿床中矿石的稀土配分曲线与其各自的新鲜及蚀变围岩的稀土配分曲线形态相似但又存在差异,说明每个矿床的新鲜围岩、蚀变围岩和矿石之间的稀土元素既具有继承性、又受到不同性质的流体的影响。居隆庵铀矿床中矿石显示Eu负异常,可能主要是继承了围岩的Eu负异常;沙洲铀矿床中矿石Eu显示弱负异常至弱正异常的特征,可能与围岩中斜长石因热液蚀变作用而释放出的Eu的进入流体有关。基于新鲜围岩、蚀变围岩及矿石的U和REE研究,推断居隆庵铀矿床成矿流体中U和REE均以F的络合物形式迁移;但沙洲铀矿床中铀矿石品位较低,可能是与流体中相对贫F有关。
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| 关 键 词： | 微量元素 稀土元素 成矿流体 居隆庵和沙洲铀矿床 相山铀矿田 |
| 收稿时间： | 2019/3/18 0:00:00 |
| 修稿时间： | 2019/7/27 0:00:00 |
Characteristics of ore-forming fluids in the Xiangshan uranium ore-field: Constraints from trace elements and rare earth elements |
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| LIU Bin,CHEN WeiFeng,FANG QiChun,MAO YuFeng,TANG XiangSheng,YAN YongJie,WEI Xing and LING HongFei.Characteristics of ore-forming fluids in the Xiangshan uranium ore-field: Constraints from trace elements and rare earth elements[J].Acta Petrologica Sinica,2019,35(9):2774-2786. |
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| Authors: | LIU Bin CHEN WeiFeng FANG QiChun MAO YuFeng TANG XiangSheng YAN YongJie WEI Xing and LING HongFei |
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| Institution: | State Key Laboratory for Mineral Deposit Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210023, China,State Key Laboratory for Mineral Deposit Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210023, China,Research Institute No. 270, CNNC, Nanchang 330200, China,Research Institute No. 270, CNNC, Nanchang 330200, China,Research Institute No. 270, CNNC, Nanchang 330200, China,Research Institute No. 270, CNNC, Nanchang 330200, China,Research Institute No. 270, CNNC, Nanchang 330200, China and State Key Laboratory for Mineral Deposit Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210023, China |
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| Abstract: | The origin of ore-forming fluids in the Xiangshan uranium ore-field are still controversial. In order to constrain chemical characters and origin of the ore-forming fluids for the Xiangshan uranium ore-field, we analyzed trace elements and REE of the ores, altered wall rocks and fresh wall rocks from the Julong''an and Shazhou uranium deposits, in western and northern parts of the Xiangshan uranium ore-field, respectively. The results show that the concentrations of Zr and Hf decrease from fresh wall rock to altered wall rocks, and increased from altered wall rocks to ores in the Julong''an uranium deposit. In contrast, in the Shazhou uranium deposit, the concentrations of Zr and Hf are basically similar among ores, fresh wall rocks and altered wall rocks. As F-rich fluid is able to leach Zr and Hf in rocks during hydrothermal fluid-rock interactions, it is inferred that the hydrothermal fluid in the Julong''an uranium deposit may have been rich in F, while the fluid in the Shazhou uranium deposit is relatively poor in F. There are similarities in REE distribution patterns among fresh wall rocks, hydrothermal altered wall rocks and ores in each deposit studied, but HREE in ores show enrichment to different extents. It indicates that in each deposit the REE characters of the ores may have been mainly inherited from the pre-alteration fresh wall rocks, but with modifications and HREE additions by the hydrothermal fluids during the alteration and mineralization. The negative Eu anomalies of ores in the Julong''an deposit may also have been inherited from the fresh wall rocks of the deposit. However, the ores in the Shazhou uranium deposit show weak negative to weak positive Eu anomalies. This may have been related with Eu release during hydrothermal alteration of plagioclase that may have been originally rich in Eu. Based on U and REE composition of fresh wall rocks, altered wall rocks and ores in the Shazhou and Julong''an uranium deposits, we advocate that U and REE in the Julong''an uranium deposit co-migrated in the form of complex with F in the hydrothermal fluid. The lower ore grade of the Shazhou uranium deposit may have been related to less F in the ore-forming fluid. |
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| Keywords: | Trace elements Rare earth elements Ore-forming fluid Julong''an and Shazhou uranium deposits Xiangshan ore field |
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