CHEN Deng1,2, LIU Zhi-chen1,2,3*, TANG Zi-cheng1, GUO Yu1, ZHANG Xiao-dong1, ZHONG Yue-li1
(1. 102 Geological Brigade of Guizhou Bureau of Geology and Mineral Resources, Zunyi Guizhou 563000, China;
2. Engineering Technology Innovation Center of Mineral Resources Exploration in Bedrock Area, Ministry of Natural Resources, Guiyang 550009, China;
3. College of Resources and Environment, Guizhou University, Guiyang 550008, China)
Abstract: A large number of fluorite deposits (mineral occurrences) are distributed in the Wuchuan-Yanhe area of Guizhou Province. Most of them are associated with barite deposits. They occurred in carbonate rocks of the Ordovician Tongzi and Honghuayuan formations, and the distribution of their orebodies is strictly controlled by the strata and the NW-trending tensile faults. In this paper, the geochemical study of rare earth elements (REE) of samples from some fluorite deposits such as the Shuanghe, Luping, Yiwanshui and Tongmushui deposits in the Fuyang area of Wuchuan County has been carried out. The results show that the REE distribution patterns of samples from fluorite deposits are all right-declined LREE-enriched ones, with their ∑REE contents ranging from 28.96×10–6 to 115.12×10–6, from 123.10×10–6 to 124.11×10–6, from 14.77×10–6 to 22.35×10–6 and from 20.73×10–6 to 123.69×10–6, respectively. In general, they have relatively strong positive Eu anomalies and negative Ce anomalies, indicating that these fluorite deposits were formed in a relatively oxidized environment. The fluorite deposits in the area belong to a medium-low temperature hydrothermal filling metasomatism type deposit controlled by the NW-trending tensile fault and the carbonate rocks of the Lower Ordovician strata. Combined with the La/ HO-Y /Ho diagrams and geological characteristics of those deposits, it is concluded that those fluorites were formed by the same sourced ore-forming fluid at different stages of the same ore-forming period. Especially, the Shuanghe deposit, a medium-scale fluorite deposit, was formed through the metallogenic superposition of three ore-forming stages. The Luping deposit is a fluorite-barite deposit formed in the early ore-forming stage, and the Yiwanshui deposit is a purple fluorite deposit formed in the late ore-forming stage. In addition, the Tongmushui and Shuanghe deposits have relatively similar geological and geochemical characteristics, suggesting that they have similar metallogenic environment and relatively great prospecting potential.
Keywords: fluorite deposit; Wuchuan; rare earth elements; geochemistry; barite
