Metallogenic Regularities and Ore Controlling Factors of Wumengou Bauxite in Shanzhou District, Henan Province

Wumengou bauxite deposit in the west of Henan Province is found to be a deep large-scale bauxite deposit in the process of the bauxite integrated exploration project under coal mines. The deposit is sedimentary karst bauxite on the surface of the paleoweathering erosion of Ordovician carbonate rock. The ore-bearing rock series is the Upper Carboniferous Benxi Formation, which is the Fe-Al mudstone combination in the Late Carboniferous. The bauxite structure of this area is mainly clastic, dense and pisolitic. The ore-forming environment is lagoon, bay, or their shore nearby. The sedimentary facies are lagoon or bay. Three medium or large- scale bauxite ore bodies are found in the area. The whole shape is layer-like, with the local being lenticular, monoclinic and not stable in thickness. The thickness of ore body is positively correlated with the thickness of ore-bearing rock series, Al₂O₃ content and A/S value. The ore bodies are characterized in vertical direction by coarse-to-fine grain sequence and rich-to-poor grade from bottom to top. The grade is not more directly related to the burial depth than the original sediment sources and sedimentary environment. The higher the degree of weathering and denudation of ore-forming provenance, the easier it is to form rich ore body. Negative topography such as karst cave, depression and karst bucket in basement affected the shape, occurrence and scale of bauxite. The occurrence elevation of the ore body influences the S content, in the later tectonic movement the elevation may raise. When it is above the local erosion datum, the bauxite ore body is in oxidation environment. Desulfurization occurs, and the s content is significantly reduced，which is conducive for the ore quality.