Investigation on protolith and tectonic setting of metamorphic rocks in the Surian complex using petrographic and geochemical data



The metamorphic rocks of the Surian complex occurred along the Bavanat Valley, northeast of Fars province at the eastern edge of the Sanandaj-Sirjan zone. The complex is located between the Surian fault in the northeast, and Jian fault in the southeast, and consists of chlorite epidote schist, chlorite actinolite schist, quartz chlorite schist, mica schist and andalusite muscovite schist. Geochemical data (Al2O3, CaO, MgO, Ni, P2O5, TiO2 and REE) contents reveal that the primary rocks of andalusite muscovite schist, quartz chlorite schist and mica schist were formed in sedimentary environments, whereas those of the chlorite actinolite schist and chlorite epidote schist have igneous origin. The concentrations of major immobile elements (e.g. Al, Ti), REE and Highs Field Strength Elements (HFSE) (e.g. Nb, Y, Zr), indicate that the rocks of sedimentary origin were formed in active continental margin setting in association with turbidites of deep sea floor and those of igneous origin show tholeiitic basalt nature of rift basins.