河南省陕州区五门沟铝土矿成矿规律及控矿因素分析

五门沟铝土矿位于河南省西部，是在中国首个实施的煤矿下部铝土矿整装勘查项目过程中发现的中深部大型隐伏铝土矿床。该矿床为产于奥陶系碳酸盐岩古风化侵蚀面上的沉积型岩溶铝土矿，其含矿岩系为上石炭统本溪组，为一套含铁富铝的铁铝质泥岩组合，形成于晚石碳世。本区铝土矿石结构以碎屑状、致密状和豆鲕状为主。成矿环境为泻湖或海湾，以及其近岸，沉积相为泻湖或海湾相。区内共发现铝土矿体3个，矿体规模为中-大型，总体形态呈似层状，局部呈透镜状，呈单斜产出，矿体厚度不稳定。矿体厚度与含矿岩系厚度、Al2O3含量、A/S值均呈较明显正相关。矿体以多种矿石类型分层产出时，垂向上表现为下粗上细的粒序特征和下富上贫的品位特征。矿体品位与埋深并无直接关系，其品位更多依赖于与原生沉积物源和沉积环境。成矿物源风化剥蚀程度越高，越容易形成品位较富的矿体。基底溶洞、洼地、溶斗等负地形控制着铝土矿的矿体形态、产状、规模；低洼处会沉积更多的含矿物质，往往形成厚大的矿体，品位较高。矿体的赋存标高对硫含量影响较大，后期构造运动可使铝土矿体标高抬升，当标高位于当地侵蚀基准面之上时，铝土矿体处于氧化环境，脱硫作用发生，硫含量显著降低，有利于提高矿石质量。

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.