| Located in the Qitianling, Hunan province, Furong tin allotment is a super-large Sn-polymer-tallic ore filed found in recent years. This allotment can be divided into threenorth-east trending tin ore belts: Bailashui-Anyuan,Heishanli-Maziping and Shangmentou–Goutouling .Rock alternation, ore structure, structural feature, ore type, mineral assemblage and zoningin Bailashui, Goutouling, shanmenkou mines have been researched by works in field and lab.Typomorphic characteristics in essential component, accessory element, unit cell parameterand infrared spectrum of sphalerite and chlorite are the primary researches in this paper.Electron-probe analysis demonstrates two kinds of sphalerite in this allotment: marmatiteand ordinary sphalerite. The content of Fe, main color causing element in sphalerite rises from0.60% to12.28%, correspondingly the color of sphalerite grows deeply. It also showsdependence in Zn-Fe and Zn-Mn. Microelement analysis indicates genetic type of Furong tinallotment is nearly magmatic hydrothermal deposit by content of In, Ga and Cd and thetemperature of mineralization is speculated about 235～248℃ by the value of LogGa/Ge, Zn/Cd,which means sphalerite occurred under mesothermal temperature.Unit cell average dimension of sphalerite in Furong tin allotment is 0.5419 nm, and it islower than the standard 0.5420 nm, which results from isomorphic replacement of Fe,Mn,Cd insphalerite. From infrared spectrum analysis of sphalerite in Furong allotment, we can observethe movement of absorption band along the low frequency.Chlorite in Furong tin allotment can be divided into two stages of mineralization. AndLeptochlorite in Goutouling mine, chamoisite in Bailashui mine and brunsvigite inWuchangping and Shanmenkou mines are concluded by Electron-probe analysis .The content ofFe is richer in this field, which demonstrates forming environment is relatively acid andFe/(Fe+Mg) of different stages of mineralization is regular. The value of Unit cell parameters a0of chlorite is lower than standard, which results from Fe3+;and absorption spectrum of Fe can beobviously observed in infrared spectrum. Forming temperature of chlorite is induced into earlystage (251～387℃) and late stage (120～187℃)by the equation based on the relation of Al~Ⅳ,Fe,Mg and temperature. Finally we get the direct correlation of Al~Ⅳ and temperature, andnegative correlation of SiⅣ and temperature.The research of chemical composition, crystal structure and temperature of mineralizationof sphalerite and chlorite provide typomorphic characteristics for ore genesis and mineralpropecting. |
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