Geological and geochemical evolution of the Bolkardagi bauxite deposits, Karaman, Turkey: Transformation from shale to bauxite

Abstract

The Bolkardagi bauxite province is located in the Tauride Belt of southern Turkey. The region hosts many lateritic- and karstic-type bauxite deposits within the Bolkardagi Unit (BU), the Namrun Tectonic Unit (NTU) and the Aladag Unit (AU). The lateritic-type deposits occur on the Upper Triassic sericite-chlorite schist of the BU, on the Lower Triassic slates, and on the Upper Triassic phyllites of the NTU. The gradual transition from the protolith to saprolite and, eventually, to bauxite is observed in the lateritic-type deposits in the field. The karstic-type deposits occur in the carbonates of the BU, the NTU and the AU and were accumulated by clastic transportation from the lateritic material. The deposits within the BU and the NTU are metamorphosed and consist mainly of diasporite, haematite, pyrophyllite, chlorite, chamosite, and anatase; the deposits within the AU are not metamorphosed and consist mainly of boehmite and kaolinite, haematite, goethite, chlorite and anatase.