Studies On Lithoficies And Geology-Geochemistry In Qinglong Antimony Deposit, Guizhou Province

In recent years, with the advanced of prospecting and exploring work of deep and periphery in Qinglong antimony deposit of Guizhou province and Dachang tin polymetallic deposit of Guangxi province , work has been made a significant breakthrough. The explanations were a little insufficient to that antimony was coexistent and associated with the other minerals (pyrite, fluorite, gold and silica) in Qinglong antimony deposit, the same as Dachang tin polymetallic which melti-minerals(Sn, Cu, Pb, Zn, Ag, Sb, In) were coexistence. Thus, the metallogenic mechanism of antimony deposit for metal’s coexistence and association in Guizhou-Guangxi region has become to one of an important issue. The paper is researching on the coexistence-association discipline and forming mechanism taken Qinglong antimony mine for example.Ore-bearing rocks-"Dachang Layer" and the upper and lower stratas were studied systematically in terms of lithofacies and geology-geochemistry. Completed with petrographic mapping, petrography mapping in tunnel, petrography mapping of core drilling etc., lithoface-types in Qinglong area were determined, especially the lithoface’s spatial distribution of "Dachang Layer ".Combined with microscope observation, the characteristics of rock and mineral were determined. Through the analysis of petrochemistry of Gulu and Sanwangping areas, geochemical characteristics were found. In this paper, we tried to use the approach of lithofacies to study characteristics of ore-bearing rocks, establish the division standard in Qinglong area and summarize the relationship between lithofacies and mineralization.Studies indicated that lithofacies of Qinglong region can be divided into volcanic outpouring facies, fall-out (air-fall) accumulation facies (tuff subfacies, tuff breccia subfacies), pyroclastic flows facies (volcanic breccia subfacies, tuff breccia subfacies), volcanic exhalatice (hydrothermal) sedimentation facies (hydrothermal synsedimentation subfacies, hydrothermal synreplacement subfacies, hydrothermal fluid pressure-fracturing and explosion subfacies, hydrothermal filling subfacies),hydrothermal filling and replacement (transformation) facies (fluorite microfacies, quartz-sulfide microfacies, pyrite microfacies, gypsum-barite microfacies) and platform of carbonate facies (open platform subfacies, marginal of platform subfacies). Emeishan basalt, tuff, tuff breccia, silicified tuff breccia, pyritized tuff, basaltic conglomerate, siliceous rock, chert, siliceous limestone, limestone and biological limestone etc. are the mainly rock types. The results of major and trace elements together with REE analysis showed that SiO2 content in "Dachang Layer" was generally high, and other components changed greatly, while some rocks had the chatracteristics of hydrothermal sedimentation.Volcanic exhalatice (hydrothermal) sedimentation widely developed on diagenetic stage, and then affected by hydrothermal filling and replacement. Silicification, pyrited rocks and carbonation were hackneyed. Therefore, author believes that volcanic exhalatice (hydrothermal) sedimentation facies and hydrothermal filling and replacement (transformation) facies played a decisive role in the relative mineralization, while the pyroclastic flows facies and fall-out (air-fall) accumulation facies played a predetermination role. The breccia’s uniformizable extent was critical to the development of mix-hydrothermal sedimentation and hydrothermal filling and replacement (transformation) function.