In situ LA-ICP-MS analyses of mica and wolframite from the Maoping tungsten deposit, southern Jiangxi, China
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ORIGINAL ARTICLE
In situ LA-ICP-MS analyses of mica and wolframite from the Maoping tungsten deposit, southern Jiangxi, China Guanghong Chen1 • Jianfeng Gao2
•
Jianjun Lu1 • Rongqing Zhang1
Received: 16 April 2020 / Revised: 4 June 2020 / Accepted: 15 July 2020 Ó Science Press and Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The Maoping tungsten deposit is located in the Nanling W–Sn metallogenic belt in South China. Greisen and quartz vein types of mineralization developed in this deposit. Protolithionite occurs in the granite. Zinnwaldite is occurs mainly in greisen and wolframite–quartz veins whereas phengite is found in the underground quartz veinlets. In granite and greisen, protolithionite, and zinnwaldite are partly replaced by Li-phengite. LA-ICP-MS trace element analyses of micas and wolframite are employed to characterize the ore-forming source and evolution of ore-forming fluids. Micas show compositional variation trend in vertical directions with a decrease of W, Sn, Nb, and Ta and an increase of MgO, V, Ni, and Co. Wolframite in greisen has higher Mo, Sn, Nb, Ta, and REEs than those in quartz veins. All wolframites show similar REE patterns with enrichment of HREE. Wolframites in greisen and quartz veins have negative Eu anomalies, while wolframites in quartz veinlet display positive Eu anomalies. Compositions of mica and wolframite from different mining levels of the Maoping deposit suggest that the ore-forming fluids are dominated by magmatic hydrothermal fluids in the deep with a slight addition of meteoric water in the shallow. Brittle fractureinduced depressurization and fluid mixing controlled the
& Jianfeng Gao [email protected] 1
State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
2
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
evolution of ore-forming fluids and possibly lead to the wolframite deposition. Keywords Mica Wolframite Magmatic-hydrothermal evolution In situ analysis Quartz-vein type W deposit
1 Introduction Tungsten deposits are widely distributed in South China Block, which accounts for more than 44% of the global W reserves (Mao et al. 2019). They occur as skarn, quartz vein, porphyry, and greisen deposits (Mao et al. 2019). Among them, quartz vein-type tungsten deposits, characterized by a high grade of wolframite, are the most important tungsten sources of the world (Li et al. 2018). The quartz vein-type tungsten deposits are related to granite and are mostly distributed in southern Jiangxi, China. Previous studies have shown that both metals and ore-forming fluids are mainly originated from highly evolved granitic magmas (Mao et al. 2019 and reference therein). However, the evolutionary histories of ore-forming fluids and the process of tungsten mineralization are still not well documented. Mica is one of the most common rock-fo
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