Peak and post-peak PT conditions and fluid composition for scapolite-clinopyroxene-garnet calc-silicate rocks from the Takab area, NW Iran

Moazzen, Mohssen; Oberhänsli, Roland; Hajialioghli, Robab; Bousquet, Romain; Droop, G. T. R.; Jahangiri, Ahmad

doi:10.1127/0935-1221/2009/0021-1887

Cited by 14 publications

(9 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our thermobarometric estimates show that the peak of metamorphism occurred under medium-to hightemperature and medium-pressure conditions, corresponding to Barrovian-type metamorphism. The calculated pressure for M 1b metamorphism is in good agreement with the pressure estimated by Moazzen et al (2009) for calc-silicate rocks. The occurrence of Barrovian-type metamorphism in the MMC is further evidence for tectonic thickening of the crust (Thompson and England, 1984).…”

Section: Discussionsupporting

confidence: 76%

“…This was followed by decompression and hydration during exhumation of the crustal rocks up to the surface. Secondary phases such as garnet (II) hornblende (II), plagioclase (II), zoisite and titanite (II) constrain the temperature and pressure of post-peak metamorphism as $6008C and $6 kbar respectively and a fluid with X CO2 as low as 0.4 (Moazzen et al, 2009). K-Ar dating of carbonaceous schists in the Zarshuran area (Mehrabi et al, 1999), apatite U-Th/He data from the Mahneshan area (Stockli et al, 2004) and 40 Ar-39 Ar dating of muscovite schists (Gilg et al, 2006), constrains the timing of rapid exhumation of the basement rocks to the Early Miocene (20 Ma).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Saki¹,

Moazzen²,

Oberhänsli³

2010

Geological Journal

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

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

Saki¹,

Moazzen²,

Oberhänsli³

2010

Geological Journal

View full text Add to dashboard Cite

show abstract

“…2007; Moazzen et al . 2009). The strips of ultramafic rocks in the Takab Complex can be interpreted as lithospheric remnants of the Proto-Tethyan, which closed during the Pan-African Orogeny (Hajialioghli et al .…”

Section: Regional Geological Settingmentioning

confidence: 99%

Mineral chemistry and thermobarometry of the staurolite-chloritoid schists from Poshtuk, NW Iran

2012

Self Cite

View full text Add to dashboard Cite

The Poshtuk metapelitic rocks in northwestern Iran underwent two main phases of regional and contact metamorphism. Microstructures, textural features and field relations indicate that these rocks underwent a polymetamorphic history. The dominant metamorphic assemblage of the metapelites is garnet, staurolite, chloritoid, chlorite, muscovite and quartz, which grew mainly syntectonically during the later contact metamorphic event. Peak metamorphic conditions of this event took place at 580 • C and ∼ 3-4 kbar, indicating that this event occurred under high-temperature and low-pressure conditions (HT/LP metamorphism), which reflects the high heat flow in this part of the crust. This event is mainly controlled by advective heat input through magmatic intrusions into all levels of the crust. These extensive Eocene metamorphic and magmatic activities can be associated with the early Alpine Orogeny, which resulted in this area from the convergence between the Arabian and Eurasian plates, and the Cenozoic closure of the Tethys oceanic tract(s).

show abstract

“…The eastern border is marked by the Pari basin. It consists of a variety of rocks including granulites, metabasites, amphibolites, migmatites, calc-silicate rocks, metaultramafics, gneisses, mica-schists and sporadically, granitoids (Hajialioghli et al 2007a,b;Moazzen et al 2009;Saki, 2010 Hajialioghli, unpub. 1b).…”

Section: Geological Setting and Field Relationsmentioning

confidence: 99%

“…Tabriz, 2007;Hajialioghli et al 2007a; Moazzen et al 2009), will furnish a framework to decipher the geodynamic history of the Takab and the adjacent areas. Ph.D. thesis, Univ.…”

Section: Introductionmentioning

confidence: 99%

Petrogenesis and tectonic evolution of metaluminous sub-alkaline granitoids from the Takab Complex, NW Iran

et al. 2010

Self Cite

View full text Add to dashboard Cite

The Takab complex is composed of a variety of metamorphic rocks including amphibolites, metapelites, mafic granulites, migmatites and meta-ultramafics, which are intruded by the granitoid. The granitoid magmatic activity occurred in relation to the subduction of the Neo-Tethys oceanic crust beneath the Iranian crust during Tertiary times. The granitoids are mainly granodiorite, quartz monzodiorite, monzonite and quartz diorite. Chemically, the magmatic rocks are characterized by ASI < 1.04, AI < 0.87 and high contents of CaO (up to ∼ 14.5 wt %), which are consistent with the I-type magmatic series. Low FeO t /(FeO t +MgO) values (< 0.75) as well as low Nb, Y and K 2 O contents of the investigated rocks resemble the calc-alkaline series. Low SiO 2 , K 2 O/Na 2 O and Al 2 O 3 accompanied by high CaO and FeO contents indicate melting of metabasites as an appropriate source for the intrusions. Negative Ti and Nb anomalies verify a metaluminous crustal origin for the protoliths of the investigated igneous rocks. These are comparable with compositions of the associated mafic migmatites, in the Takab metamorphic complex, which originated from the partial melting of amphibolites. Therefore, crustal melting and a collision-related origin for the Takab calc-alkaline intrusions are proposed here on the basis of mineralogy and geochemical characteristics. The P-T evolution during magmatic crystallization and subsolidus cooling stages is determined by the study of mineral chemistry of the granodiorite and the quartz diorite. Magmatic crystallization pressure and temperature for the quartz-diorite and the granodiorite are estimated to be P ∼ 7.8 ± 2.5 kbar, T ∼ 760 ± 75 • C and P ∼ 5 ± 1 kbar, T ∼ 700 • C, respectively. Subsolidus conditions are consistent with temperatures of ∼ 620 • C and ∼ 600 • C, and pressures of ∼ 5 kbar and ∼ 3.5 kbar for the quartz-diorite and the granodiorite, respectively.

show abstract

Peak and post-peak PT conditions and fluid composition for scapolite-clinopyroxene-garnet calc-silicate rocks from the Takab area, NW Iran

Cited by 14 publications

References 49 publications

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

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

Mineral chemistry and thermobarometry of the staurolite-chloritoid schists from Poshtuk, NW Iran

Petrogenesis and tectonic evolution of metaluminous sub-alkaline granitoids from the Takab Complex, NW Iran

Contact Info

Product

Resources

About