Geological And Geochemical Studies Of Bauxite Ore Deposits Metallogenic Belt, SW Henan, China

Bauxite deposits in the SW Henan region are mainly distributed in the area among Jiaozuo, Sanmenxia and Pingdingshan. Bauxite ores were occured in the carboniferous carbonate middle in Benxi group which was on the top of weathered ordovician (or Cambrian) carbonate sequences, and they are referred to as karst-type deposits. The character of the sequence obviously was controlled by the ancient karst topography, and the sequence from the bottom to up basically is iron, silicon, aluminum, and silicon aluminum (iron) alternating layers. From west to east the distribution of mines shows obvious zonality. Doline funnel and karst depression are the most common types of ancient karst ore in the studied area. We can find that aluminium mineral is given priority to with diaspore in every mining area of Sanmenxia-Mianchi-Xin’an ore belt and Yiyang-Ruyang-Lushan ore belt. But they contain the different main clay minerals, the former is given priority to with kaolinite, the latter mainly is illite from the analysis of X-ray diffraction mineral rock samples.Geochemical analyses indicate that there are some obvious differentiations among trace elements which are in carbonate rocks and in aluminum rock series, and there are also small differences among trace elements which are from different cell layers. Element B has obvious correlation with some of the elements which are in bottom of the limestone and iron clay rocks, and this can explain that iron clay stone formed in sea facies environment, and it also indirectly explains that the bauxite formed in sea facies environment. But the enrichment of element B in bauxite shows that carbonate rocks which are low of containing aluminum rock series and are rich in B were likely plausible source materials from which the bauxite deposits were formed.The content of REE in bauxite is low in the whole SW Henan, which can show that parent rock of bauxite is likely to be from the backplane carbonate, because the amount of rare earth elements in carbonate is the lowest in the sedimentary rocks. In the order of highest to lowest amount of rare earth elements in rocks is that bauxite> other containing aluminum rock series> the weathering crust of carbonate rocks or iron-base, which suggests that the amount of rare earth elements is gradually enriched during the weathering process, and the content of rare earth elements in ore-bearing rock series has positively proportional relationship with the content of rare earth elements in clay mineral. During the process of bauxite to mineralize, the activity and proportion of light rare earth elements are much stronger and more than heavy rare earth elements’. Eu negative anomaly shows the relative consistency in ore-bearing layer of the whole region department units.