Springer Iranian Journal of Science 2731-8095 39 2 2015 06 14 The Kasian volcanic rocks, Khorramabad, Iran: Evidence for a Jurassic Intra-Oceanic island arc in Neo-Tethys ocean 165 178 3013 10.22099/ijsts.2015.3013 EN Zarasvandi A. Department of Geology, Faculty of Earth Science, Shahid Chamran University (SCU), Ahvaz, Iran M. Rezaei Department of Geology, Faculty of Earth Science, Shahid Chamran University (SCU), Ahvaz, Iran D. Lentz Department of Earth Sciences, University of New Brunswick, New Brunswick, Canada Pourkaseb H. Department of Geology, Faculty of Earth Science, Shahid Chamran University (SCU), Ahvaz, Iran M. Karevani Department of Earth Sciences, University of New Brunswick, New Brunswick, Canada Journal Article 2014 11 27   <br /><span style="font-size: xx-small;">The Kasian volcanic body is located in the eastern margin of the Zagros thrust belt, close to the Sanandaj-Sirjan metamorphic zone. These volcanic rocks are mainly composed of andesite and andesite-basalt rocks with porphyritic, hypocrystalline porphyritic, hyalo-porphyritic and hyalo-microlitic porphyritic textures. Analyses of the distributions of major, rare earth and trace elements reveal a tholeiitic nature and evidence such as enrichment of Pb and LILE (e.g., U, Rb, Ba), depletion in HFSE (e.g., Nb, Ti, Y), slight enrichment of LREE relative to HREE and trace elements discrimination plots reveal island arc affinity for the Kasian volcanic rocks. Some characteristics like, low Nd/Pb and Ce/Pb values (average 8.76 and 12.70, respectively), high U values and low Nb/U ratios (average 3.52) indicate enrichment of mantle wedge by contribution of slab-derived fluids during dehydration of subducting slab of Neo-Tethys oceanic lithosphere. Moreover, the results show these volcanic rocks to have fractionated as they ascended to higher crustal levels. The results of this study are consistent with the new tectonic scenario for the Sanandaj-Sirjan zone, which suggests that during ocean–ocean subduction (from Jurassic to Cretaceous) an immature island arc developed before the closure of Neo-Tethys ocean. </span> https://ijsts.shirazu.ac.ir/article_3013_9e5abcb0f0f30ec01fe78fc03e2f3d75.pdf