Abstract:

The Yushan bauxite ore deposit in the western Henan Province is a large concealed deposit discovered by Henan Institute of Geological Survey in 2005, which belongs to layer-G bauxite of North China Platform. The deposit-bearing strata of the Upper Carboniferous can be divided into two facies and further to four microfacies according to the systemic analysis of drilling data, i.e. lithologic association, sedimentary structure and chemistry feature of the allite series. The allite series of Yushan bauxite is formed in sedimentary environment of the shallow marine such as the coastal, the tidal flat or the lagoon, and the bauxite is mainly developed with the microfacies of oolitic (or classic) deposit that is formed in the upper part of restricted subtidal zone. Importantly, the allite series of the Yushan bauxite is the product resulting from a complex process of three cycles from the rapid transgression to the slow regression that form three bauxite sequences from the bottom to the upper part correspondingly, and the bauxite sequence with the large-scale distribution is formed in the last large-scale transgression-regression cycle. Therefore, this study is a good complement for the theory of bauxite formation in Carboniferous Benxi Formation in the North China Platform.

Key words: sedimentary environment, Yushan bauxite ore deposit, western Henan Province