Geochemistry Characteristics And Genesis Of Madiu Fluorite Deposits In Luanchuan Region, Henan

Luanchuan Mo-W-Pb-Zn-Ag polymetallic metallogenic concentration area is not only abundant with metallic mineral resources but also with large amount of fluorite resources. Geotectonically, this area is located in the southern margin of North China Craton, with Middle Proterozo Xiong’er Group largely exposed and fluorite deposit normally hosted in Heyu granite. Based on the analysis of detailed geological research and lab tests, this article researches Madiu fluorite deposits by adopting modern metallogenic theory, and focuses on analyzing geological characteristics, geochemical characteristics, and geological genesis of fluorite deposits. The main results and conclusions are summarized as follows:1. This article bewrites the ore bodies characteristics of Madiu fluorite deposit, ore material components, ore texture and structure, wall rock alteration, and other geological features. Luanchuan Madiu fluorite deposit in Henan Province, which is strictly controlled by fractures, belongs to hydrothermal-type deposit.2. The geochemical results of rare-earth element(REE) show that the fluorite deposit is low in REE but high in LREE. It forms from the third to the second to the first middle mining tunnel, with all the tunnels equipped with similar characteristics: negative in Eu, strong reducibility in ore-forming fluid and lack of Ce.3. Fluid inclusion research shows that pure liquid inclusions and liquid inclusions are two main types of inclusions, which are big in size, clear in periphery and clustered in forms. Microthermometry results suggest that the average temperature of the three mining tunnels ranges between 140 ~ 180 ℃,that the salinity ranges between 0.18%~2.07%NaCleqv, that the density ranges between 0.76~0.94g/cm3, and that the depth of mineralization ranges between 0.747~1.028 km. By adopting the geochemical results and geological characteristics, it shows that the fluorite deposits in these three middle mining tunnels probably come from the same epoch and homologous fluid, and that Madiu fluorite deposit is low temperature hydrothermal type deposit.4. By analyzing the rare-earth element(REE) and geological evolution, it is proposed that the material F forming fluorite deposits mainly comes from the surrounding rocks, that the material Ca mainly comes from the surrounding rocks and stratum and that water-rock reaction is probably the principal mechanism of fluorite precipitation.