University of Isfahan Petrological Journal 2228-5210 8 30 2017 08 23 Petrology, geochemistry and petrogenesis of volcanic band rocks in North of Tabriz, NW Iran Petrology, geochemistry and petrogenesis of volcanic band rocks in North of Tabriz, NW Iran 15 30 21947 10.22108/ijp.2017.81968 FA Mahdiyeh Fazelihagh Department of Earth Sciene, Natural Science Faculty, Tabriz University, Tabriz, Iran Nasir Amel Department of Earth Sciene, Natural Science Faculty, Tabriz University, Tabriz, Iran Ahmad Jahangiri Department of Earth Sciene, Natural Science Faculty, Tabriz University, Tabriz, Iran Journal Article 2015 12 04 The studied volcanic rocks are located in 35 km North West of Tabriz and consists of dacite, andesite, basalt and basaltic andesite. Based on structural geology evidences, this area is part of west Alborz – Azerbaijan zone. Plio - Quaternary volcanism is started with explosive eruptions of acidic and intermediate materials and in last and young stage basaltic lava erupted from faults and fractures that are visible with layered structure. Prismatic basaltic lavas covered pyroclastic rocks and andesitic lavas. The main constituent minerals in these rocks are olivine, plagioclase, amphibole and pyroxene. In the diagram to determine the magmatic series, samples belong to two magmatic series calc-alkaline and alkaline and show characteristics of bimodal magmatism. Studied volcanic sequence show a reverse volcanic series that it is results of characteristics of bimodal volcanism. In spider diagrams which normalized with chonderite and primitive mantle  amounts, these rocks show enrichment of HREE and HFSE elements and depletion of LREE and LILE like Ti, Nb and Ta (TNT). According to the trace elements diagrams La to La / Sm and La / Yb to Yb ratio, magma genesis can be formed from a low rate of partial melting of garnet lherzolite mantle and with ascending and emplacement of magma in the upper level of the crust partial melting of crustal rocks produced acidic and intermediate volcanic materials. Tectonomagmatic diagrams show that these rocks formed in post collision volcanic arcs.  The studied volcanic rocks are located in 35 km North West of Tabriz and consists of dacite, andesite, basalt and basaltic andesite. Based on structural geology evidences, this area is part of west Alborz – Azerbaijan zone. Plio - Quaternary volcanism is started with explosive eruptions of acidic and intermediate materials and in last and young stage basaltic lava erupted from faults and fractures that are visible with layered structure. Prismatic basaltic lavas covered pyroclastic rocks and andesitic lavas. The main constituent minerals in these rocks are olivine, plagioclase, amphibole and pyroxene. In the diagram to determine the magmatic series, samples belong to two magmatic series calc-alkaline and alkaline and show characteristics of bimodal magmatism. Studied volcanic sequence show a reverse volcanic series that it is results of characteristics of bimodal volcanism. In spider diagrams which normalized with chonderite and primitive mantle  amounts, these rocks show enrichment of HREE and HFSE elements and depletion of LREE and LILE like Ti, Nb and Ta (TNT). According to the trace elements diagrams La to La / Sm and La / Yb to Yb ratio, magma genesis can be formed from a low rate of partial melting of garnet lherzolite mantle and with ascending and emplacement of magma in the upper level of the crust partial melting of crustal rocks produced acidic and intermediate volcanic materials. Tectonomagmatic diagrams show that these rocks formed in post collision volcanic arcs.  https://ijp.ui.ac.ir/article_21947_a6d6b1c7fc73151356ef4a57e9b7421b.pdf