Abstract:

The bauxite deposits in southeastern Yunnan Province are typical karst bauxite deposits. The orebo-dies occur in the Upper Permian Wujiaping Formation (Longtan Formation). It is significant to analyze geochemical characteristics of this deposit for the material source of bauxite ores. Whole rock analysis reveals Al₂O₃, Fe₂O₃ , SiO₂ and TiO₂ are the main components of the bauxite ores. And Al₂O₃ has a negative relationship with Fe₂O₃ and SiO₂. Trace elements such as Cr, Zr, Hf, Ta, Th, U and REE were enriched during the bauxitization process. Elements of Zr and Hf, Nb and Ta display significant correlation with each other. Studies of bivariate plots of lgCr-lgNi, immobile elements ratios such as Zr/Hf, and REE pattern suggest that the Emeishan basalts are the major source of materials for the bauxite formation. And the underlying limestones may provide some source of materials for the formation of bauxite ores.

Key words: geochemistry, source of ore-forming materials, southeastern Yunnan Province