Whole rock and mineral chemistry of hornblenditic xenoliths in volcanic alkaline rocks from the northern part of Uromieh Dokhatar magmatic belt (NW Iran)

An alkaline volcanic activity with a relative Plio-Quaternary age (based on the succession of layers field) occurred in northern part Uromieh Dokhatar magmatic belt, Iran. Hornblendite xenoliths mostly displaying cumulitic texture occur trachyandesites from this episode. The thermobarometric results indicate that these formed within crust. Based mineralogical and chemical characteristics, are divided into two groups. In Group 1, plagioclase (andesine) modal content is less than 10% while amphibole (magnesiohastingsite) biotite main minerals. 2, (labradorite) higher 20% (pargasite) Positive anomalies U, Ba, Ti, K hornblendite probably related to accumulation process biotite. study composition amphiboles indicates crystallization 1 2 host rock under high oxidation conditions. display LREE/HREE LREE/MREE ratios. 86 Sr/ 87 Sr ratios Groups rocks 0.706291, 0.704685, 0.709545, respectively, 143 Nd/ 144 Nd 0.512580, 0.512736, 0.512561, respectively. characterized by negative Eu anomaly positive for 2. Considering REE concentrations distribution patterns, major element compositions amphibole, biotite, as well isotopic ratios, it appears parental melts differ composition. Those theoretical also have different when compared rock. studied commonly located along faults. Therefore seems movement faults (especially North Tabriz Fault, Misho Tasuj faults) has provided path lavas carrying investigated penetrate continental Taken together geochemical characteristics mantle source variably metasomatized subduction event prior collision between Eurasian Arabian continents.