M Ghorbani; M.R Hosseinzadeh
Abstract
The mafic-ultramafic complex of Misho is exposed in in the northwestern part of Iran, in the East Azerbaidjan province (southwest of Marand). This complex intruded in the older rock units including the Kahar formation and resulted in developing of contact metamorphic rocks. Compositionally, the mafic ...
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The mafic-ultramafic complex of Misho is exposed in in the northwestern part of Iran, in the East Azerbaidjan province (southwest of Marand). This complex intruded in the older rock units including the Kahar formation and resulted in developing of contact metamorphic rocks. Compositionally, the mafic portion is gabbronorite, troctolite and olivine-gabbronorite; and the ultramafics are harzburgite to lherzolite. The EPMA analyses of main minerals in mafic rocks (gabbro) show that plagioclases are anorthite to bytownite, Olivines are mainly chrysolite, orthopyroxenes have enstatitic composition, clinopyroxenes are diopsidic and amphiboles are tschermakite, to tschermakitic hornblende. Geothermobarometery of gabbros based on varions methods (Al2O3 and TiO2 in amphibole, plagioclase - amphibole and orthopyroxene – clinopyroxene) yield 700- 900ºC in pressure of 7-8 kbar.
G. Ahmadzadeh; A. Jahangiri; M. Mojtahedi; D. Lentz
Abstract
In this paper the study of Plio-Quaternary post-collisional magmatism in northwest of Iran and northwest of Marand is considered. The studied Potassic and ultrapotassic (UP) alkaline rocks were erupted at northern part of Urumieh-Dokhtar magmatic arc (UDMA). The studied rocks dispaly microlithic porphyritic ...
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In this paper the study of Plio-Quaternary post-collisional magmatism in northwest of Iran and northwest of Marand is considered. The studied Potassic and ultrapotassic (UP) alkaline rocks were erupted at northern part of Urumieh-Dokhtar magmatic arc (UDMA). The studied rocks dispaly microlithic porphyritic texture with phenocrysts of clinopyroxene, leucite, and plagioclase ± biotite ± olivine. The UP volcanic rocks are mostly silica undersatuated with normative nephline, high Mg# and high K2O/Na2O ratios. They characterized with significant enrichment in LILEs and LREEs and depletion in high field strength elements such as Nb, Ta and Ti. Exhibit high Ba/Nb (41-60) and Ba/Ta (682-1139) ratios, which are a typical feature of subduction. With considering end of subduction (upper cretaceouse) and stratigraphic age of studed rocks (plio-quaternary), we can say that these rocks has formed in post collisional environment and metasomatic mantle due to addition of volatiles and incompatible elements lead to enrichment of these magmas. And in fact we can say that the subduction properties of these rocks inherited from an ancient subduction. On the otherhand, high contents of LILE such as Th and Ba and Ba/Nb, Ba/Ta ratios indicate the involvement of crustal components in genesis of these rocks by addition of crustal components to source and contamination through ascent of magma. Rare earth elements modeling indicate that they can be generated from low degree partial melting of lithospheric mantle with garnet-spinel peridotite source.
R. Shabanian; M. Parvanehne-Nezhad Shirazi; F. Javadinia
Abstract
The detailed stratigraphical and lithological analysis of the Permian sequence in north Marand, NW of Iran at Harzand village has been studied . At this locating the Permian sequence consist of Dorud (82 m..) Surmaq (258 m..) and Julfa (108 m.) formations respectively. The main lithology consist ...
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The detailed stratigraphical and lithological analysis of the Permian sequence in north Marand, NW of Iran at Harzand village has been studied . At this locating the Permian sequence consist of Dorud (82 m..) Surmaq (258 m..) and Julfa (108 m.) formations respectively. The main lithology consist of white to red sandstone, grey to dark, biogenetic limestone , marly limestone and thin bedded limestone. The lower boundary is non conformity, so that the Permian sequence is underlying a thick extrusive igneous rocks and at the top, a sequence of Miocene red clastic deposit covers the Permian sequence with disconformably. In this study 52 foraminiferal species belonging to 37 genus and 8 species of 9 Algal genus were recognized and 4 assemblages biozones in Surmaq and Julfa formations have identified. Based on fossils assemblages , the age of the Surmaq formations is Kubergandian - Murgabian (Middle Permian) and the age of Julfa formation is Middian - Early Dzhufian Stages(Late middle –Early late Permian).
