Bolkardağı bauxite deposits at Ayrancı, Karaman, Central Turkey. Part 2. Mineralogical and petrographical studies

The studied area is located 15 km southeast of Ayrancı (Karaman) district, covering an area of about 300 km². The aim of this study is the petrographic definition of the bauxite. For this purpose thin and polished sections of over 30 samples from bauxite were examined that and X-ray Diffraction (XRD) analyses were carried out. In the area, there is a Permian - Cretaceous aged rock of the Bolkardağı unit which is one of the tectonic nappes, overburden by Miocene aged formations. The bauxite ore bodies are observed between dolostone and limestone which belong to the Upper Permian Dedeköy Formation. The bauxite is taught because of it became terrestrial emerging during Late Triassic-Early Jurassic (?) period. The bauxite consists of different amounts of diaspore, hematite, and clay minerals. Ore paragenesis is reported as diaspore, hematite, kaolinite, anatase, rutile, sphene, calcite, muscovite, magnetite, quartz, goethite, chlorite, amourphous iron- and aluminum-hydroxide, gibbsite, boehmite, illite, specularite, epidote, chalcedony, amphibole and psilomelane. Inside bauxite, different ore types which have different appearance can be defined. These different appearances emerge essentially depending on the prevalence of diaspore, hematite and clay minerals, and they pass into vertical and horizontal transitions to each other. These ore types are black bauxite, brown bauxite, oolitic bauxite and clayey bauxite.