XU Yang-dong, QI Lian-su, YIN Ting-long, CHEN Zhi, DONG Shu-hui^*, ZHENG Qian-fei

(Institute of Geophysical and Geochemical Prospecting, Bureau of Geology and Mineral Resources Exploration and Development of Guizhou Province, Guiyang, 550018, China)

Abstract:. The Donggualin fluorite deposit is a representative medium-sized fluorite deposit newly discovered in the southeast of the Dachang antimony deposit in Qinglong City of the southwestern Guizhou. There is a small amount of associated antimony ore in the deposit. In this paper, on the basis of the geological survey of the fluorite deposit, we have analyzed geochemical characteristics of trace elements and rare earth elements of fluorites and wallrock samples, and have made comparitive study with the trace element compositions of associated fluorites of the Dachang antimony deposit, in order to analyze the origin of the Donggualin fluorite deposit and to explore its source of ore-forming materials. The results show that all fluorite samples have significantly enriched Sb and Ti, and relatively enriched Y, but depleted other elements compared with the upper crust. All fluorite samples have similar REE distribution patterns, and relatively low total contents of the REE. Their ∑REE contents vary from 12.7×10^-6 to 32.7×10^-6, with the average value of 18.5×10^-6. They have similar REE compositional characteristics of the associated fluorites in the Dachang Antimony Mine of Qinglong City. Meanwhile, all fluorite samples have weakly negative Eu anomalies (δEu: 0.79-0.96, average of 0.87), and obviously negative Ce anomalies (δCe: 0.65-0.79, average of 0.71). Their REE distribution patterns are similar to those of associated fluorites in the Dachang Antimony Mine of Qinglong City. It is speculated that the Donggualin fluorite deposit and the Dachang antimony deposit could be formed in a same metallogenic system which is of the low temperature hydrothermal origin. The fluorite and antimony mineralization could be formed in a relatively reduced environment. In addition, the ore-forming materials of the Dongguanlin fluorite deposit could be mainly sourced from all kinds of wallrocks (carbonates and basalt). The interaction between the ore-forming fluid and wallrocks, that is, the water/ rock reaction could be an important factor leading to the enrichment and precipitation of fluorite in this area.

Keywords: Donggualin fluorite deposit; trace elements; rare earth elements; ore genesis; Qinglong