Mineralogy and geochemistry of major, trace and REE elements, Pirashkaft Bauxite Deposits, Mamasani, Fars Province

The Pirashkaft bauxite deposit is located in north of the Paskuhak anticline in the Fars Province. The bauxite deposit present between Sarvak and Gurpy Formations, and formed during the Late Turonian time as a consequent of the Laramid orogeny phase. According to the geological investigations, the Pirashkaft bauxite is  Karstic type. The residual ore studied in the Pirashkaft can be classified into three groups: 1) kaolinite bauxite, 2) bauxite and 3) ferrite bauxite. Petrographically, pisolithic–oolithic is the most important texture. Mineralogically, the main minerals include boehmite, hematite, diaspore and kaolinite and minor minerals comprised of: gibbsite and rutile. The major oxides in the bauxite horizons mainly included: Al2O3 (37.88- 55.45wt%), SiO2 (2.01- 30.49wt%), Fe2O3(10.14- 36.71wt%) and LOI ( 9.72- 15.32wt%). There is a strong positive correlation between Al2O3 and TiO2, and also an enrichment of LREE (136.49- 928.56 ppm) relative to HREE (16.48-59.5 ppm) is observed in the bauxitic horizons.  The Eu / Eu* anomaly of the bauxite samples ranges between 0.26 and 0.99. Positive anomaly of Ce / Ce* between 1.2 and 2.33, indicates the dominant oxidation during bauxitization.