University of Isfahan Petrological Journal 2228-5210 9 1 2018 05 22 The role of crustal contamination and differentiation in the formation of the Eocene volcanic rocks in Jirande area (Northwest of Qazvin) The role of crustal contamination and differentiation in the formation of the Eocene volcanic rocks in Jirande area (Northwest of Qazvin) 71 90 22503 10.22108/ijp.2017.82007.0 FA Seyede Somayeh Teimouri Department of Geology, Faculty of Earth Sciences, Payame Noor University, Iran Habibollah Ghasemi Department of Geology, Faculty of Science, Shahrood University of Technology, Shahrood, Iran Abbas Asiabanha 1 Department of Geology, Faculty of Science, Imam Khomeini International University, Qazvin, Iran 0000-0002-4652-960X Journal Article 2016 06 16 The Eocene volcanic rocks in Jirande area are dominated by basalt, andesite, trachyt and trachyandesite, which range from basic to intermediate rocks. Plagioclase as major mineral in igneous rocks makes up the largest percentage mineral in these rocks. Clinopyroxene and olivine in basaltic rocks and amphibole in acidic rocks are the prevalent minerals. In petrological studies, the existence of glomeroporphyry, sieve, corrosion gulf, skeletal, and also reaction rims confirm the role of crustal contamination and fractional crystallization in the evolution of the study rocks. Also, variation diagrams of trace elements, spider diagrams together with AFC modeling and ratio-ratio diagrams of trace elements, highlights the role of crustal contamination and magmatic fractionation in the genesis of the rocks studied. The parent magma of  these rocks, have a composition like as the melts derived from enriched mantle, and plots in the field of 10-20 percent partial melting of a garnet-spinel lherzolitic source in the depth of 90 to 110 km. The Eocene volcanic rocks in Jirande area are dominated by basalt, andesite, trachyt and trachyandesite, which range from basic to intermediate rocks. Plagioclase as major mineral in igneous rocks makes up the largest percentage mineral in these rocks. Clinopyroxene and olivine in basaltic rocks and amphibole in acidic rocks are the prevalent minerals. In petrological studies, the existence of glomeroporphyry, sieve, corrosion gulf, skeletal, and also reaction rims confirm the role of crustal contamination and fractional crystallization in the evolution of the study rocks. Also, variation diagrams of trace elements, spider diagrams together with AFC modeling and ratio-ratio diagrams of trace elements, highlights the role of crustal contamination and magmatic fractionation in the genesis of the rocks studied. The parent magma of  these rocks, have a composition like as the melts derived from enriched mantle, and plots in the field of 10-20 percent partial melting of a garnet-spinel lherzolitic source in the depth of 90 to 110 km. https://ijp.ui.ac.ir/article_22503_75a39e85ae259f435e9aa6e2109fc5d0.pdf