Petrology of gabbroic- dioritic intrusions in the Parishan Mountain (south of Qorveh), Kurdistan


1 Department of Geology, Faculty of Sciences, Bu-Ali Sina University, Hamedan, Iran

2 همدان- خیابان شهید فهمیده- دانشگاه بوعلی سینا- گروه زمین شناسی


The gabbroic intrusion of the Parishan Mountain in the south of Qorveh (Kurdistan province) is located between the villages of Zarrineh to Tekyeh-bala and based on structural divisions, it is a part of the Sanandaj-Sirjan zone. Based on petrographic features it consists of hornblende-pyroxene gabbro, gabbro, quartz-gabbro, dioritic gabbro, diorite and quartz-diorite rocks. Geochemical studies indicate that magma has metaluminous and calc-alkaline nature with medium potassium. Variation diagrams trends don’t confirm the continuous chemical between the samples. The negative correlation between the variations of SiO2 against oxides of Mg, Fe and Ca suggest fractional crystallization process for both of magmas. Tectonic setting discrimination diagrams indicate that magma depends to volcanic arc in active continental margin of related subduction zones. LREE enrichment in comparison to HREE and LILE enrichment and depletion of elements (i.e. Ti, Zr, Nb and Ta) can be due to crustal contamination and dependence of the body to subduction zones. The low Mg# value, high SiO2 contents, positive Yb and negative Ho anomalies suggest that mafic magma was originated from a metasomatized mantle, which it has melted lower crust. The linear and positive trends of incompatible elements against each other, suggests the role of fractionation crystallization in the mafic-intermediate magmas. Furthermore, field relationship and petrographic evidences show that mingling process of two magmas, including mafic and felsic magmas (intermediate), which are consistent with the tectonic setting of the studied area.