Geochemical and Mineralogical Findings of Pertek (Tunceli) Fe-Skarn Mineralization: Preparation to Its Origin

Abstract

The Southeast Anatolian Orogenic Belt (SAOB), one of the most important belts in Turkey, is located north of the Bitlis-Zagros Suture Zone. Major iron mineralizations are also observed along this belt. The Pertek (Tunceli) region is one of the dominant Fe-Skarn mineralisations. Keban Metamorphites of Permo-Carboniferous age forms the basement of the region. It is mainly represented by metacarbonates, marbles and schists, respectively. This unit is also cut by intrusive rocks from the Upper Cretaceous Elazığ Magmatic Complex (EMC). Tertiary volcanic rocks and sedimentary rocks also overlie both units with angular unconformity. Fe-Skarn was formed at the contact of carbonates belonging to Keban Metamorphites and diorites belonging to EMC. Macroscopically, magnetite crystals and garnet can be observed in the skarn formation, which is easily distinguished by its colour. Polarizing microscopy revealed quartz, calcite, garnet, pyroxene, chlorite and opaque minerals. X-ray diffraction (XRD) analysis revealed that the garnet is andraditic, and the ore minerals are magnetite and hematite. In the ore microscopy, it was determined that magnetite was first transformed into hematite and then hematite into goethite. Regarding the major oxide concentrations of the samples taken from the region, it was determined that the Fe2O3 value reached a maximum of 60% (average 21.94%), SiO2 (average 38.20%) and CaO (average 23.58%) concentrations were high, and Al2O3 concentration was generally low. Al2O3 concentration reaches 17.96 % in the sample where clayification is common. The findings of this study provide a baseline for identifying the origin of the Pertek Fe-Skarn formation.