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| 新疆别也萨麻斯矿区钽锰矿的矿物学特征及其TIMS U-Pb定年 | |
| 引用本文： | 何晗晗,艾尔肯&#;吐尔孙,王登红,王瑞江,陈振宇.新疆别也萨麻斯矿区钽锰矿的矿物学特征及其TIMS U-Pb定年[J].岩矿测试,2020,39(4):609-619. |
| 作者姓名： | 何晗晗 艾尔肯&#;吐尔孙 王登红 王瑞江 陈振宇 |
| 作者单位： | 北京市地质调查研究院, 北京 100195;自然资源部成矿作用与资源评价国家重点实验室, 中国地质科学院矿产资源研究所, 北京 100037;新疆维吾尔自治区有色地质勘查局701队, 新疆 昌吉 831100 |
| 基金项目： | 中国地质调查局地质调查项目“中国矿产地质志”项目（DD20190379，DD20160346）；国家重点研发计划项目“我国锂能源金属成矿规律、靶区优选与重点查证”课题（2017YFC0602701）；中国地质调查局中国矿产地质志项目（DD20190379-95） |
| 摘 要： | 钽矿是我国的紧缺资源,近年来对别也萨麻斯地区钽矿取得了找矿新进展,包括新矿点的发现以及花岗伟晶岩型稀有金属资源的找矿突破。区内伟晶岩脉广泛发育,为探究含矿脉体的成矿时代、查明区内典型铌钽矿物的矿物学特征,本文以L18号伟晶岩脉中的钽锰矿为研究对象,对其物理性质、化学成分、地质年代等进行了分析。应用电子探针测试钽锰矿的化学组成,热电离质谱法(TIMS)测定其U-Pb年龄,确定含矿脉体的形成年代。结果表明,研究区钽锰矿中Ta_2O_5含量为51.58%～74.80%,均值68.49%,Nb_2O_5含量为6.15%～27.63%;部分主量元素分布不均,未表现出规律的分带性,但矿物颗粒中心部位的CaO含量较边部低,横剖面上SiO_2含量相对稳定,TiO_2与WO_3显示不规律波动。这种特征表明钽锰矿并非单纯由结晶分异作用形成,而是可能受到了后期交代作用的影响。钽锰矿的U-Pb年龄为160Ma,说明钽锰矿化发生于晚侏罗世早期,与围岩海西期二云母花岗岩相差甚远,后者并非L18号脉体的成矿母岩。 |
| 关 键 词： | 钽锰矿 别也萨麻斯矿区 稀有金属 伟晶岩脉 TIMS U-Pb测年 铌钽矿 |
| 收稿时间： | 2019/12/15 0:00:00 |
| 修稿时间： | 2020/3/1 0:00:00 |
Mineralogical Characteristics and TIMS U-Pb Dating of Tantalite-(Mn) from the Bieyesamas Rare Metal Deposit, Xinjiang |
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| HE Han-han,ARKIN Tulson,WANG Deng-hong,WANG Rui-jiang,CHEN Zhen-yu.Mineralogical Characteristics and TIMS U-Pb Dating of Tantalite-(Mn) from the Bieyesamas Rare Metal Deposit, Xinjiang[J].Rock and Mineral Analysis,2020,39(4):609-619. | |
| Authors: | HE Han-han ARKIN Tulson WANG Deng-hong WANG Rui-jiang CHEN Zhen-yu |
| Institution: | Beijing Institute of Geological Survey, Beijing 100195, China;Key Laboratory of Metallogeny and Mineral Assessment, Ministry of Natural Resources;Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;701 Team of Non-ferrous Geological Exploration Bureau of Xinjiang Uygur Autonomous Region, Changji 831100, China |
| Abstract: | BACKGROUND: Tantalum is a scarce resource in China. A new breakthrough in ore prospecting was obtained on the tantalum ore in the Bieyesamasi area, Xinjiang, including new occurrences as well as the exploration of pegmatite-type rare metal resources. OBJECTIVES: To explore the mineralization age of ore-bearing veins and the mineralogical characteristics of typical columbite-tantalite minerals, tantalite-(Mn) from L18 pegmatite veins, and to evaluate one of the most distinctive minerals in this area. METHODS: Electron microprobe was used to characterize mineralogy of tantalite-(Mn), and TIMS U-Pb geochronology of this mineral was used to constrain the age. RESULTS: The content of Ta2O5 in tantalite-(Mn) from L18 pegmatite veins ranged from 51.58% to 74.80%, with an average of 68.49%, while Nb2O5 contents varied from 6.15% to 27.63%. Some of the major elements were unevenly distributed and did not show regular banding, with the CaO content in the center of a mineral particle lower than at the edge, and the SiO2 content relatively stable in the cross section. TiO2 and WO3 showed irregular fluctuations. This feature indicated that the tantalite-(Mn) was not formed solely by crystal differentiation, but may be affected by later metasomatism. CONCLUSIONS: TIMS U-Pb dating of tantalite-(Mn) yields an age of 160Ma, indicating that the mineralization of L18 pegmatite was formed in the early period of Late Jurassic, different from the surrounding Hercynian granite. It is inferred that Hercynian granite is not the source of L18 pegmatite vein. |
| Keywords: | tantalite-(Mn) Bieyesamasi deposit rare metals pegmatite vein TIMS U-Pb dating columbite-tantalite ore |
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