Geological And Geochemical Studies Of Bauxite Metallogenic Belt Of Sanmenxia, Henan

China is abundant of bauxite deposit resources which located in northern andsouthern of the country. Henan is one of the most important sources which producebauxite resources. Bauxite deposits in this province, which showed as classical karstbauxite deposits, distributed in the middle-low member of Benxi formation inCarboniferous strata and above the fossil erosion surface of middle Ordoviciancarbonatite.Successions of ore-bearing strata varied in our research area. The successions ofore-bearing strata consequence, which showed obvious changes and classifications ofstrata from east to west, was controlled by paleo-karst terrain obviously. Karstdepression and karst funnel were the main kinds of deposits controlled by paleo-karst.Generally there were two layers of bauxite distributed in the Karst depression, Ore-bearing horizon sequence is generally in order from bottom to top: underlyingcarbonate, weathering crust of ferric, ferric claystone, bauxitic claystone, bauxite,bauxitic claystone, bauxite, claystone/mudstone, coal seams/coal line, roofsandstone or limestone;while only one in the karst funnel, Ore-bearing horizonsequence is generally in order from bottom to top: underlying carbonate, weatheringcrust of ferric, ferric claystone, bauxitic claystone, bauxite, claystone/mudstone, coalseams/coal line, roof sandstone or limestone.Due to observations in outdoors andunder microscopes, we found out the structure of bauxite ores is simple, mainlymassive ores. Cryptocrystalline texture is the majority texture, with much less oolitic and clastictextures.According to feasible testing methods results, we learned that diasporite was themost important ore minerals. Clay minerals were mainly glimmertons and kaolinites,some chlorites, also, with oysanite and minor amount of goethite, zircon.Terrigenousperiod， syngenetic, mineralizing, late mineralize and hypergene periods wererecognized as the five main ore-forming stages.Geochemical analyses revealed that Al₂O₃, Fe₂O₃, SiO₂and TiO₂are the maincomponents of the bauxite ores and trace elements such as Zr、Hf、 Nb、 Ta、 Th and U were enriched during the bauxitization process. Al₂O₃vs. Fe₂O₃displays anegative correlation and Al₂O₃vs. TiO₂displays a positive correlation. TiO₂vs. high-intensity magnetic field element（Zr, Hf, Nb and Ta） show a positive correlation. Itillustrates that Ti and high-intensity magnetic field element（Zr, Hf, Nb and Ta） has thesame geochemical behaviour and all of them are stabilized during the weatheringprocess.The weathered residues in mineral, Immobile elements ratios such as Zr/Hf,Nb/Ta, bivariate plots of Eu/Eu*and TiO₂/Al₂O₃, and REE patten suggest thatQinling-Dabie orogenic belt were the main source of materials for the bauxiteformation.Besides, while the bottom plate carbonate rocks are also involved in theformation of bauxite.