Petrography and geochemistry of Cretaceous bauxites from Jajce, Bosnia and Herzegovina

Abstract

The study presents petrographic and compositional data of Late Cretaceous bauxite deposits in the area of Jajce, Bosnia and Herzegovina. Results indicate that bauxites exhibit ooidic to pisodic textures enclosed within a pelitomorfic matrix. Most of the deposits are boehmitic but in some localities, a considerable quantity of diaspore is identified. Hematite is the dominant Fe-mineral, while kaolinite, goethite and calcite are minor. The accessory minerals are represented by anatase, rutile and zircon. Al2O3 content ranges between 54.32–61.05 wt % and is negatively correlated to Fe2O3. Rare earth elements (REE) show variable concentrations, reaching up to 1353 ppm. The chondrite normalized patterns reveal negative Eu anomaly in all and positive Ce anomaly in almost all samples. Ce anomaly shows negative correlation with REE. Bauxites from the Jajce area represent valuable mineral resource with potentially valuable quantities of REE and Sc. Mineralogy and geochemical signature indicate a complex petrogenetic history.