Azna granitoid as an example of syn-collision S-type granitisation in Sanandaj-Sirjan metamorphic belt, Iran

Moazzen, Mohssen; Moayyed, M; Modjarrad, Monir; Darvishi, Esmail

doi:10.1127/0028-3649/2004/2004-0489

Cited by 23 publications

(11 citation statements)

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“…Afro-Arabian plate and Iranian microplates and subsequent continental collision (during Cretaceous to Early Tertiary) caused metamorphism and associated magmatism in the Sanandaj-Sirjan Zone (Şengör, 1984;Mohajjel et al, 2003;Moazzen et al, 2004). On the other hand, the Alborz Mountains on the north of the Central Iran Zone are the result of closure of Palaeo-Tethyan oceanic crust at a southdipping subduction zone, corresponding to the Cimmerian Orogeny (Zanchi et al, 2006).…”

Section: Introductionmentioning

confidence: 97%

Mineralogy, geochemistry and geodynamic setting of the granitoids from NW Iran

Saki

2010

Geological Journal

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The Mahneshan granitoids intruded the Neoproterozoic-Lower Cambrian regional metamorphic rocks in northwestern Iran. These granitoids consisting mainly of K-feldspar, plagioclase, quartz, muscovite, garnet and biotite display a number of subtypes in terms of structure, texture and mineralogy. Geochemically, they are peraluminous and (or) slightly peraluminous with variable normative corundum contents (0.28-4.50%), and medium to high potassic with calc-alkaline affinity. Chondrite-normalized REE patterns indicate that these granitoids can be divided into three distinct groups, supported by petrographic data. The REE patterns of the first group are shallow-sloping in LREE relative to HREE ([La/Yb]n ¼ 1.37-2.48), exhibiting pronounced negative Eu (Eu/Eu Ã ¼ 0.23-0.35). The second group granitoids are characterized by strong LREE-enrichment relative to HREE ([La/Yb]n ¼ 3-6.20), with positive Eu anomalies (Eu/Eu Ã ¼ 1.15-1.47). The third group of granitoids is depleted in the middle REE relative to other LREE and HREE. These REE patterns suggest the role of plagioclase and hornblende in their source of granitoids for group 1 and groups 2 and 3, respectively. The trends of Eu/Eu Ã ratio versus silica contents suggest mixing of mafic material with components formed by crustal melting with a plagioclase-rich residue. Furthermore, thermobarometric estimations indicate that these rocks may have been formed at depths of 15-18 km at relatively low temperatures. The Mahneshan granitoids are S-type and may have been emplaced in a syn-to post-collisional tectonic setting, consistent with an origin of water-saturated magmas with heterogeneous composition derived from different crustal rocks.

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Section: Introductionmentioning

confidence: 97%

Mineralogy, geochemistry and geodynamic setting of the granitoids from NW Iran

Saki

2010

Geological Journal

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“…These bodies, are small in extent, mainly Cretaceous to Early Oligocene ages, and are widespread in the southeastern extremity of the SSZ (Darvishzadeh and Khosrow-Tehrani, 1984;Aghanabati, 2004). Some of these plutons (Kolah-Ghazi, Muteh) display S-type characteristics (Khalili and Khalili, 2002;Moazzen et al, 2004). Some have I-type nature (Borujerd, Ghorveh, Astaneh) (Ahmadi Khalaji et al, 2007;Turkian, 2008;Tahmasbi, 2009) and some others (Almogholagh, Saqqez, Hasan-Robat, Azna) are classified as A-type granites (Sepahi and Athari, 2006;Mansouri Esfahani et al, 2010;Shabanian, 2009).…”

Section: Geological Setting -Field Relationsmentioning

confidence: 96%

The significance of mafic microgranular enclaves in the petrogenesis of the Dehno Complex, Sanandaj–Sirjan belt, Iran

Rajaieh

Khalili

Richards

2010

Journal of Asian Earth Sciences

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“…This belt extends across Iran in a NW-SE direction (Figure 1). Subduction of Neo-Tethys between the Afro-Arabian Plate and Iranian microplates and subsequent continental collision (during Cretaceous to Early Tertiary) caused metamorphism and associated magmatism in the Sanandaj-Sirjan Zone (Sengör, 1984;Mohajjel et al, 2003;Moazzen et al, 2004). On the other hand, the Alborz Mountains to the north of the Central Iran Zone are the result of closure of Palaeo-Tethyan oceanic crust at a south-dipping subduction zone, corresponding to the Cimmerian Orogeny (Zanchi et al, 2006).…”

Section: Introductionmentioning

confidence: 97%

P–T evolution of the Precambrian Metamorphic Complex, NW Iran: a study of metapelitic rocks

Saki¹,

Moazzen²,

Oberhänsli³

2010

Geological Journal

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The Mahneshan Metamorphic Complex (MMC) is one of the Precambrian terrains exposed in the northwest of Iran. The MMC underwent two main phases of deformation (D 1 and D 2 ) and at least two metamorphic events (M 1 and M 2 ). Critical metamorphic mineral assemblages in the metapelitic rocks testify to regional metamorphism under amphibolite-facies conditions. The dominant metamorphic mineral assemblage in metapelitic rocks (M 1 ) is muscovite, biotite I, Garnet I, staurolite, Andalusite I and sillimanite. Peak metamorphism took place at 600-6208C and $7 kbar, corresponding to a depth of ca. 24 km. This was followed by decompression during exhumation of the crustal rocks up to the surface. The decrease of temperature and pressure during exhumation produced retrograde metamorphic assemblages (M 2 ). Secondary phases such as garnet II biotite II, Andalusite II constrain the temperature and pressure of M 2 retrograde metamorphism to 520-5608C and 2.5-3.5 kbar, respectively. The geothermal gradient obtained for the peak of metamorphism is 338C km À1 , which indicates that peak metamorphism was of Barrovian type and occurred under medium-pressure conditions. The MMC followed a 'clockwise' P-T path during metamorphism, consistent with thermal relaxation following tectonic thickening. The bulk chemistry of the MMC metapelites shows that their protoliths were deposited at an active continental margin. Together with the presence of palaeo-suture zones and ophiolitic rocks around the high-grade metamorphic rocks of the MMC, these features suggest that the Iranian Precambrian basement formed by an island-arc type cratonization.

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Azna granitoid as an example of syn-collision S-type granitisation in Sanandaj-Sirjan metamorphic belt, Iran

Cited by 23 publications

References 0 publications

Mineralogy, geochemistry and geodynamic setting of the granitoids from NW Iran

Mineralogy, geochemistry and geodynamic setting of the granitoids from NW Iran

The significance of mafic microgranular enclaves in the petrogenesis of the Dehno Complex, Sanandaj–Sirjan belt, Iran

P–T evolution of the Precambrian Metamorphic Complex, NW Iran: a study of metapelitic rocks

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