GEOLOGICAL CHARACTERISTICS AND ORE-CONTROLLING FACTORS OF SHIFOSI BAUXITE DEPOSIT IN YICHUAN COUNTY, HENAN PROVINCE

The Shifosi bauxite deposit in Yichuan is one of the medium-sized bauxite deposits newly discovered in Longmen-Gongyi bauxite metallogenic belt in western Henan Province, with the ore-bearing rock series in the middle and lower part of Upper Carboniferous Benxi Formation. The bauxite deposit is occurred on the ancient weathered denudation surface of carbonate rocks of Cambrian Gushan Formation, which is in conformable contact with the overlying Taiyuan Formation. The Benxi Formation is composed of iron-bearing clays and bauxite layers from bottom to top. The immediate roof of bauxite orebody is I₁ coal seam with a thickness of 0.80-1.60 m, and the immediate floor is high ferrallitic clay rock of 1.40-3.50 m thick. The natural types of ores are mainly oolitic, clastic bauxites and their mixtures, with the main bauxite mineral of diaspore, generally containing gallium, which is recyclable. The mineralization is mainly controlled by strata, paleostructure, lithofacies paleogeography, paleoclimate and weathering, genetically belonging to paleo-weathering crust sedimentary type.