Whole rock chemistry of Shahindezh metapelites, provenance and mineral parageneses

In order to identify the provenance of metasediments of the Shahindezh Metamorphic Complex (SMC), NW Iran, we have studied the bulk chemistry of the metapelites in the mentioned area. The geochemistry of these rocks suggests that the parent sedimentary rocks are classified as shale. Major and trace elements concentration (e.g. TiO2, K2O, Ni, Rb) indicates that the primary igneous rock was acidic (andesite to rhyodacite). The chemical index of alteration (CIA) show that the source rocks have undergone moderate to high degree of chemical weathering and plagioclase composition varies from andesine to oligoclase. Using major oxides elements, the continental active margin is considered for SMC metapelites source. In comparison with average upper continental crust, the SMC metapelites show strong negative Ca and Sr anomalies and slight depletion in Nb and Mn but moderate enrichment in Y, Ba, Al and transitional elements. The similarity in the trends of multi-elements diagrams for all studied samples shows that bulk chemistry factor was constant variant at the different mineral paragenesis appearance process. Based on the standard PT pseudo sections, drown by scientists for average metapelitic composition, Ms+Bt+St and Ms+Bt+St+Ky paragenesis were in equilibrium at the PT conditions estimated, previously.