Geochemical and mineralogical properties of karst types bauxite, Catkoy, Taurus Mountains, Turkey

Abstract In recent years, studies on the geochemical, mineralogical properties and ore types of bauxite have become a significant area of research. The study area is situated within the boundaries of Catkoy within the Taurus Mountains region. The aim of this study is to determine the mineralogical and petrographic properties of bauxites and to classify bauxite ores based on macro observations. It also aims to determine the parent material of bauxite ores by analyzing the geochemical properties of bauxite, terra rossa, and the adjacent rocks. The samples were subjected to chemical analysis using inductively coupled plasma-mass spectrometry and mineralogical investigation using X-ray diffraction and microscopic techniques. The bauxite is composed of varying proportions of diaspore, hematite, and clay minerals. The ore paragenesis study has been observed to comprise diaspore, hematite, kaolinite, anatase, rutile, sphene, calcite, muscovite, magnetite, quartz, goethite, chlorite, amorphous iron- and aluminum-hydroxide, gibbsite, boehmite, illite, specularite, epidote, chalcedony, amphibole, and psilomelane. The internal composition of bauxite allows for the identification of distinct ore types, characterized by varying appearances. The ore types under consideration are black bauxite, brown bauxite, oolitic bauxite and clay bauxite. The chemical composition of bauxites is typically 54% Al 2 O 3 , 26% Fe 2 O 3 , 5% SiO 2 , 3% TiO 2 and less than 1% other major oxides. The modulus values of these bauxites exhibit a range of 1.4–91.2, with an average of 34.66. It is therefore concluded that they are of first quality. The geochemical data lend support to the hypothesis that limestone was transformed into terra rossa, which in turn was transformed into bauxite. It is believed that bauxite ores were formed before metamorphism and continued to be formed for a long time after metamorphism. Bauxites were formed during the Late Triassic to Early Jurassic interval on Upper Permian-aged carbonate rocks and Lower Triassic-aged shale, sandstone, and limestone units. Subsequently, they were deposited in caves and dolines within the carbonate rocks.