List of Articles Plio-Quaternary

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  1 - Petrogenetic Evolution of Plio-Quaternary Mafic Lavas in Nehbandan (East Iran)
  Mohammad Reza Ghasempour Javad Mehdipour Ghazi Habib Biabangard Rahim Dabiri
  Both the Sistan Suture Zone of eastern Iran and the Nehbandan Fault contain Plio-Quaternary Nehbandan mafic lavas. Positive anomalies in the large ion lithophile elements (LILE) and negative anomalies in Nb (niobium) exist in these mafic lavas. This indicates the occurr More

  Both the Sistan Suture Zone of eastern Iran and the Nehbandan Fault contain Plio-Quaternary Nehbandan mafic lavas. Positive anomalies in the large ion lithophile elements (LILE) and negative anomalies in Nb (niobium) exist in these mafic lavas. This indicates the occurrence of subduction magmatism and post-collision volcanism. Petrologic and geochemical analyses distinguished two groups of lava. Group I contains alkaline basalts with a slight depletion in Nb while Group II contains sub-alkaline basaltic andesite to andesite with a sharp depletion in Nb. Geochemical studies show that fractional crystallization and crustal contamination played an important part in the evolution of the Nehbandan lavas. Group II, however, was more greatly affected than Group I. Geochemical studies also indicate that these lavas may have been generated due to a low degree of partial melting (<5%) of garnet and the spinel-bearing lithospheric mantle; Group I shows more garnet than spinel while Group II shows the opposite. The research carried out for this paper suggests that the Plio-Quaternary Nehbandan mafic lavas were formed as a result of slab detachment or delamination and domination, an extensional condition correlated to the thinning of the crust and lithosphere in the Sistan Collision Zone. These conditions are concomitant with localized stretching along the Nehbandan Fault and the upwelling of magma forming mafic lavas. Manuscript profile
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  2 - Mineralogy, Petrography and Petrogenesis of Sahand Volcanic Suite (Northwest Iran)
  Farhad Pirmohammadi Ali Ameri Ahmad Jahangiri Mansoor Mojtahedi Mahmat Keskin
  Southeast Tabriz, Sahand volcanic rocks with Plio-Quaternery age located in the northwest part of Central Iran.These rocks are mainly composed of pyroclastics (tuff and ignimberite) and lava flows (rhyolite, rhyodacite,dacite and andesite) that unconformably cover the M More

  Southeast Tabriz, Sahand volcanic rocks with Plio-Quaternery age located in the northwest part of Central Iran.These rocks are mainly composed of pyroclastics (tuff and ignimberite) and lava flows (rhyolite, rhyodacite,dacite and andesite) that unconformably cover the Miocene sedimentary formations. The major constituentminerals include plagioclase and hornblende which is surrounded by a matrix of fine grained and glassy.Theirtexture are porphyritic. Heterogenous mineralogy, field and textural evidences such as sieve texture inplagioclase, resorption rims in crystals, oscillatory zoning in plagioclase, high normative quartz and roundedenclaves suggest that the primary magma undergone magmatic evolution including fractional crystallization ,fractionation, contamination and magma mixing during ascending. There are mineralogical as well asgeochemical evidences that AFC-type processes were involved in the evolution of the Sahand volcanic rocks.The chemistry of the felsic- intermediate volcanic rocks indicates that the parent magmas are medium-K calcalkaline and metaluminous in nature. The volcanic rocks display highly fractionated REE patterns, with nonegative Eu anomaly. Their geotectonic environment is post-collision and continental margin arcs. Manuscript profile