| Lengshuikeng deposit in Jiangxi Province, one of the most important Silver-Lead-Zinc deposits in China, consists of two types of mineralization, namely porphyry and stratabound-telescope which has special ore-forming features. On the basis of the field regional geological surveys and ploting a map of Madi-bishan Road section, this paper focus on typical ore sections and sphalerite from Xiabao stratabound mine by microscope indoors. The occurrences characteristics, chemical composition and geochemical characteristics of the sphalerites yielded from Xiabao mine, a typical stratabound-telescoped deposit, were investigated by using electron-microprobe and LA-ICP-MS. Moreover,the mathematical statistics methodology was applied to further analyze the geological conditions of the sphalerites'and in order to study on genesis of Xiaobao ore deposit as well as its ore-forming mechanism. The results show that: (1) According to the content of Fe in sphalerite andthe paragenetic association of the minerals, the sphalerites can be divided into two generations: sphalerites of generationâ… , mostly black-blackish brown, blackish red-fancy red in polarizing microscope, are of high iron content in which galena, pyrite and arsenopyrite inclusions as well as large amounts of chalcopyrite and pyrrhotite exsolutions were observed. However, generationâ…¡generally show brownish red-orange, orange-light yellow in polarizing microscope with low iron content and relatively high internal clarity, in which chalcopyrite and pyrrhotite exsolutions were rare, while natural silver acanthite or argentite were often observed. (2) The crystal chemical formula of sphalerite samples were calculated based on electron microprobe data with a mean of (Zn0.8840Fe0.1121Mn0.0015)0.9976S, lacking of Zn. In addition, the color of sphalerites becomes much lighter with the Fe content decreasing. (3) Electron microprobe data and LA-ICP-MS results detecting both major and trace elements revealed that the variation of Zn and Fe contents in sphalerites showed distinct negative correlation, the correlative relationship RZn-Fe=-0.9827, moreover, the variation of Zn and Cd contents indicated negative correlation (RZn-Cd =-0.6567). The contents of trace elements Mn, Ge, Se, Te, and Bi increased, while the content of In and Cu decreased gradually from generationâ… sphalerites to generationâ…¡. (4) Combining the paragenetic association of the minerals with the Fe contents(evenly 6.27Wt%), the contents of trace elements as well as Zn/Cd, Ga/In and Ga/In ratio in sphalerites, it indicated that the formation temperature of sphalerites concentrated in medium temperature, namely 200300℃. (5) The comparison between the trace element characteristics of sphalerites from this area and from other typical ore deposits and the application of graphic methods (Cd-In,In-Ga+Ge-Se+Te,Zn/Cd-Se/Te-Ga/In)suggested that sphalerites from Xiabao deposit is mainly magmatic-hydrothermal-type, also have the characteristics of the genesis of metamorphism and stratabound type. In summary, the genesis of sphalerites is the superimposition-reformation of sedimentarytype, metamorphic type and magmatic-hydrothermal- type deposits.
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