摘要
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 evolution of ore-forming fluids and possibly lead to the wolframite deposition.
基金
the National Key R&D Program of China(2016YFC0600207)
Key Program of Natural Science Foundation of China(41830428)
the"CAS Hundred Talents"Project to JF Gao.We are grateful to Dr.Juan Li at the School of Earth Sciences and Engineering,Nanjing University for taking BSE images.We also thank the staff of the Nanjing FocuMS Technology Co.Ltd.for their kind help in in situ LA-ICP-MS analysis.Finally,thanks for Helene Legros,Lili Chen,Guanglai Li,and Zeying Zhu's help and advice.