A Geochemical and Geostatistical Approach to the Origin of the Sarfaryab Bauxite Deposits, Kohgiloyeh-va-Boyrahmad Province, SW Iran

The Sarfaryab bauxite deposits occur in karstic depressions at the top of the limestones of the Cenomanian to Lower Turonian Sarvak Formation, which are overlain by the limestones of the Santonian Ilam Formation. In order to determine the possible source rocks of the Sarfaryab bauxite deposits, a few samples were collected from Sarvak Formation, terra rossa and bauxite ore and geochemically and geostatistically analyzed. Plots of chemical data and correlation coefficients show that Al, Ti, Zr, Nb, Cr and V were immobile during the bauxitization process. In the scatter diagrams of Zr and TiO2 versus Al2O3, regression lines pass through the origin and terra rossa falls between the Sarvak Formation and bauxite. Based on this research, it can be stated that the source rock of the Sarfaryab bauxite deposits is the Sarvak Formation and terra rossa is an intermediate product during limestone-bauxite transformation. Post-Turonian uplift had exposed recently deposited limestones of the Sarvak Formation to karst weathering, and a layer of argillaceous debris accumulated on its surface and was partly converted to bauxite. Subsidence followed, and the bauxite was preserved by the deposition of limestones of the Ilam Formation. Uplift in Pliocene time, with ensuing erosion, exposed the bauxite deposits to their present situation.