TY - JOUR A1 - Moazzen, Mohssen A1 - Oberhänsli, Roland A1 - Hajialioghli, Robab A1 - Moeller, Andreas A1 - Bousquet, Romain A1 - Droop, Giles A1 - Jahangiri, Ahmad T1 - Peak and post-peak P-T conditions and fluid composition for scapolite-clinopyroxene-garnet calc-silicate rocks from the Takab area, NW Iran N2 - The Takab calcareous rocks of northwest Iran crop out in association with a variety of metamorphic rocks including mafic granulites, amphibolites, granitic gneisses, pelitic schists and meta-ultramafic rocks. They can be divided into marbles and calc-silicate rocks on the basis of the dominance of calcite/dolomite and silicate minerals. Dominant peak metamorphic granulite facies assemblage of calc-silicate rocks is Scp + Grt(I) + Cpx + Cal + Qtz +/- Hbl(I). The decrease of temperature and pressure during exhumation produced post-peak metamorphic assemblages. Coronal garnet (Grt II) in the calc-silicate rocks was produced by retrograde reactions consuming plagioclase and clinopyroxene, while peak metamorphic garnet (Grt I) occurs as preserved xenoblastic grains in calcite and/or plagioclase (Pl II). Regional metamorphism took place at 740 degrees C and X-CO2 similar to 0.9. Garnet-clinopyroxene-plagioclase-quartz (GADS) barometry yields a pressure of 8-9 kbar, corresponding to a depth of ca. 24-27 km. 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 similar to 600 degrees C and similar to 6 kbar respectively and a fluid with XCO2 as low as 0.4. Halogens were near-absent during the peak metamorphic stage. The scapolite and hornblende crystallized underpeak metamorphic conditions contain very low fluorine and chlorine, whereas relatively high fluorine (similar to 0.8 wt%) in the titanite (II) and hornblende (II) suggests a possible infiltration of F-rich fluids into the calc-silicate rocks during retrogression. It is interpreted to be related to external fluids released during crystallisation of granitoid magmas and/or leucosome patches in the adjacent migmatites. Y1 - 2009 UR - http://eurjmin.geoscienceworld.org/ U6 - https://doi.org/10.1127/0935-1221/2009/0021-1887 SN - 0935-1221 ER - TY - JOUR A1 - Hajialioghli, Robab A1 - Moazzen, Mohssen A1 - Jahangiri, Ahmad A1 - Oberhänsli, Roland A1 - Mocek, Beate A1 - Altenberger, Uwe T1 - Petrogenesis and tectonic evolution of metaluminous sub-alkaline granitoids from the Takab Complex, NW Iran JF - Geological magazine N2 - 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 similar 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 similar to 7.8 +/- 2.5 kbar, T similar to 760 +/- 75 degrees C and P similar to 5 +/- 1 kbar, T similar to 700 degrees C, respectively. Subsolidus conditions are consistent with temperatures of similar to 620 degrees C and similar to 600 degrees C, and pressures of similar to 5 kbar and similar to 3.5 kbar for the quartz-diorite and the granodiorite, respectively. KW - granitoids KW - partial melting KW - Neo-Tethys KW - Takab KW - NW Iran Y1 - 2011 U6 - https://doi.org/10.1017/S0016756810000683 SN - 0016-7568 VL - 148 IS - 2 SP - 250 EP - 268 PB - Cambridge Univ. Press CY - New York ER - TY - GEN A1 - Hajialioghli, Robab A1 - Moazzen, Mohssen A1 - Jahangiri, Ahmad A1 - Oberhänsli, Roland A1 - Mocek, Beate A1 - Altenberger, Uwe T1 - Petrogenesis and tectonic evolution of metaluminous sub-alkaline granitoids from the Takab Complex, NW Iran T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 570 KW - granitoids KW - partial melting KW - Neo-Tethys KW - Takab KW - NW Iran Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413100 SN - 1866-8372 IS - 570 ER -