Geochemical characteristics of the Arbanos karst-type bauxite deposit, NW Iran: Implications for parental affinity and factors controlling the distribution of elements

The Arbanos bauxite deposit is located in the Iran-Himalayan karst-type bauxite belt and about 25 km northeast of Bukan city, northwestern Iran. The bauxite ores occur as layers and lenses along the contact of the carbonate (limestone and dolomite with intercalations of shale) of the Ruteh Formation (Upper Permian) and dolomite of the Elika Formation (Triassic). Hematite, kaolinite, and diaspore are the major rock-forming minerals in the ores, accompanied by lesser amounts of chlorite, montmorillonite, chamosite, siderite, goethite, boehmite, calcite, rutile, anatase, zircon, and quartz. Mass balance calculations indicate that the distribution of Ni, V, and Cr is controlled by the iron oxyhydroxides, whereas the distribution of Ba and Sr is controlled by kaolinite. The bivariate diagrams of the Sm/Nd versus the conservative elemental indices such as TiO2/Al2O3, Al2O3/Hf, Al2O3/Nb, and Nb/Ta reveal that the shale of the Ruteh Formation is the most plausible parent rock for the bauxite ores. The factor analysis method indicates that the paleo-environmental changes, soil redox state, and water activity in the pedogenic environments played a fundamental role in distribution of the major, minor, and trace elements.