Geochemical behavior of rare earth elements (REEs) during hydrothermal alteration in the Euch- Palang area (NE Kashmar, East of Central Iran)

The Euch-Palang area located in the NE of the Kashmar city, is part of Central Iran structural Zone. Eocen volcanic and pyroclastics rocks with intermediate composition (andesite to latite) associated with are exposed in the area. Based on field, petrography and geochemistry, propylitic, quartz- phyllic (sericitic) and argillic- silicic alteration zones could be identified in this area. These zones show notable differences in REE behavior. The propylitic alteration zone contains mineral assemblage of chlorite, epidote, carbonate, sericite, apatite, iron oxides, titanite, zeolite, clay minerals and pyrite. It can be divided into two sub-zones of carbonate–chlorite and carbonate–epidote. In the carbonate–chlorite sub-zone, REE are commonly depleted, with the LREE relatively more depleted than the HREE.