Geochemistry and Petrogenesis of volcanic rocks from the Arousan-e- Kaboudan (NE of Anarak)

The volcanic complex of the (NE Nain) is part of Central Iran (Yazad block). This complex consists of intermediate to acidic volcanic rocks and includes dacite, trachyandesite, shoshonite and potassic trachybasalt Mineralogical characteristics such as chemical composition of clinopyroxene (diopside to augite), and high Mg number of biotites as well as geochemical ratios of Th/Yb, Ce/Yb, and Ta/Yb indicate that lavas are shoshonitic in nature. The lack of Eu anomaly is an indicative of high oxygen fugacity, a diagnostic feature of shoshonitic magmas. The pattern of rare earth elements and spider diagrams show LREE and LILE enrichment and HFSE (Ti, Ta, Nb) depletion which are the characteristics of subduction related magmas. Geochemical studies reveal that in addition to fractional crystallization, crustal contamination and magma mixing affected on the evolution of magma which has produced the volcanic rocks in the studied area.Based on the accomplished modeling, the source rock has possibly been a garnet amphibolite (including 0-10% garnet content) liable for generating the study volcanic rocks.