University of Isfahan Petrological Journal 2228-5210 9 2 2018 06 22 "Mineralogy, geochemistry and tectonic setting of paleogenic volcanic lavas in southwest of Basiran, South of Lut Block, Eastern Iran" "Mineralogy, geochemistry and tectonic setting of paleogenic volcanic lavas in southwest of Basiran, South of Lut Block, Eastern Iran" 183 204 23498 10.22108/ijp.2018.108759.1067 FA Siavash Omidianfar Department of geology, Faculty of earth science, University of shahid Beheshty, Tehran, Iran Mohammad Rahgoshay Professor, Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University of Tehran, Tehran, Iran Iman Monsef Assistant professor, Department of Geology, Institute of advanced studies in basic sciences of Zanjan, Zanjan, Iran Journal Article 2017 12 27 The Paleogene volcanic rocks in southwest of Basiran belong to the Lut Block volcanic–plutonic belt in eastern Iran. The studied rocks range from basaltic to rhyolitic compositions (basalt, andesite, dacite and rhyolite) with a peak in intermediate compositions. These rocks are dominated by porphyritic and glomeroporphyric textures with microlitic groundmass. Geochemical evidence reveals that they have typical features of calc-alkaline, high-K calc-alkaline to shoshonitic rocks. Generally, enrichment in LILEs (like Cs, K, U and Th) rather than HFSEs (like Nb, P, Zr and Ti), negative anomalies of Nb and Ti and high LREEs/HREEs ratio in these rocks are similar to magmatic rocks in subduction zones. Positive anomalies of Pb show involvement of continental crust in evolution of parental magma. However, geochemical difference of acidic and basic-intermediate rocks may be resulted from more evolved nature of acidic magma compared to basic-intermediates or alteration effects. Based on geochemical characteristics and tectonic discrimination diagrams the studied volcanic rocks presumably formed in an immature to normal continental arc setting. Furthermore, primitive magma of basic-intermediate associations could be generated by low degree partial melting (less than 5%) of mantle peridotite (garnet lherzolite) in depth of 90-110 km. The Paleogene volcanic rocks in southwest of Basiran belong to the Lut Block volcanic–plutonic belt in eastern Iran. The studied rocks range from basaltic to rhyolitic compositions (basalt, andesite, dacite and rhyolite) with a peak in intermediate compositions. These rocks are dominated by porphyritic and glomeroporphyric textures with microlitic groundmass. Geochemical evidence reveals that they have typical features of calc-alkaline, high-K calc-alkaline to shoshonitic rocks. Generally, enrichment in LILEs (like Cs, K, U and Th) rather than HFSEs (like Nb, P, Zr and Ti), negative anomalies of Nb and Ti and high LREEs/HREEs ratio in these rocks are similar to magmatic rocks in subduction zones. Positive anomalies of Pb show involvement of continental crust in evolution of parental magma. However, geochemical difference of acidic and basic-intermediate rocks may be resulted from more evolved nature of acidic magma compared to basic-intermediates or alteration effects. Based on geochemical characteristics and tectonic discrimination diagrams the studied volcanic rocks presumably formed in an immature to normal continental arc setting. Furthermore, primitive magma of basic-intermediate associations could be generated by low degree partial melting (less than 5%) of mantle peridotite (garnet lherzolite) in depth of 90-110 km. https://ijp.ui.ac.ir/article_23498_f8f508b958f9f36f85bf70e8417db9ed.pdf