Sm-Nd isochronal age and trace element geochemistry characteristics of scheelite in Xingluokeng tungsten deposit,Fujian Province
The super giant Xingluokeng tungsten deposit is located in the eastern part of Ninghua County,Fujian Province.It is the largest tungsten deposit in the Wuyishan metallogenic belt,and it has the characteristics of large reserves,low grade,similar resources of wolframite and scheelite.As a tungsten-bearing mineral,the forma-tion age of scheelite can represent the metallogenic age of the deposit,and its geochemistry characteristics reflect the metallogenic environment and process.Based on the investigation of the characteristics of tungsten veins and the occurrence of scheelite and wolframite in the Xingluokeng tungsten deposit,the separated scheelite were used for Sm-Nd isochron dating and trace element testing.The results show that the crystallization age of scheelite is(142.6±2.8)Ma,which is slightly smaller than the in situ U-Pb age of(150.5±8.1)Ma of wolframite and the Rb-Sr isochronal age of quartz fluid inclusions of(147.5±2.9)Ma,it is consistent with the forming age of 143.5～149.5 Ma of the concealed intrusion within errors and with the temporal relation of mineral crystallization,both belong to the product of Late Jurassic magmatic activity,indicating that tungsten mineralization has the same age as or a little later than the concealed intrusive rock body.The characteristics of trace and rare earth elements in scheelite show that the first generation ore-forming fluid contains Eu3+＜＜Eu2+,indicating that the stage 1 ore-form-ing fluid is reductive fluid,and the second generation ore-forming fluid contains Eu3+＞＞Eu2+,indicating that the ore-forming fluid evolved to oxidizing fluid in stage 2.The mineralization of the Xingluokeng tungsten deposit is closely related to the Mesozoic large-scale mineralization in South China with specific tectonic setting and dy-namic environment.
scheelitemetallogenic agetrace element characteristicscharacteristics of ore-forming fluidsXingluokeng tungsten deposit
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