TY - JOUR T1 - Petrogenesis of volcanic rocks in the NW of Bam TT - پتروژنز سنگهای آتشفشانی شمال غرب بم JF - jsci JO - jsci VL - 16 IS - 41 UR - http://jsci.khu.ac.ir/article-1-2271-en.html Y1 - 2015 SP - 1 EP - 2 KW - Rhyolite KW - Andesy Basalt KW - Eocene KW - Metasomatized mantle KW - Bam N2 - In the North of Bam city there were extensive volcanism and outcrops are basic and felsic volcanic rocks that crosscut by various dykes The volcanic rocks have sub alkaline and calc-alkaline to shoshonitic characteristic, however dykes are alkaline and potassic in nature. In the spider diagram all samples show enrichment in the LILEs and depletion and troughs in the HFSs elements that coincide with subduction related and upper crust rocks features. The studied samples represent enrichment in the LREE with various (La/Yb)N ratio and rhyolites show clear trough in Eu. According to geochemical features, studied rocks generated from different sources. Trachy andesy basalts and trachy andesites formed from 1-10% partial melting of metasomatized spinal lherzolite source. Dacitic magma generated from partial melting of mafic source in the lower crust while rhyolites formed from partial melting of metagreywacke source. The olivine basaltic and basaltic dykes generated from less than 1% and 3-5% partial melting of metasomatized garnet- spinel- bearing lherzolitic mantle source, respectively. Eocene volcanism in the Bam area has been occurred during subduction of Neo-Tethys oceanic crust beneath central Iran in the continental volcanic arc tectonic setting. M3 ER -