The composition of the major minerals in the Nasrand intrusive rocks and its dikes


1 School of Geology, College of Sciences, University of Tehran, Tehran, Iran

2 کردستان سنندج دانشگاه کردستان


The Nasrand intrusion, in the central part of Uromieh-Dokhtar magmatic belt is mainly composed of granite and granodiorite. The intrusive rocks are hosted by various dikes trending NW-SE. The granites and granodiorites are dominated by plagioclase, K-feldspar, quartz, biotite, amphibole, whereas the dikes are characterized b similar mineralogy in addition to pyroxene. The amphiboles are calcic with (Na+K)A≤0.5 and magnesio -hornblende composition in the granitic rocks with (Na+K)A>0.5 and AlIV3 are magnesio-biotites. The pyroxenes in the studied dikes are clinopyroxene with augite composition. The mineral chemistry of the biotites, amphiboles and pyroxenes indicate that this intrusion is calc-alkaline and have been crystallized in a subduction zone setting.