Petrological Journal

Study of structure and morphology of zircons in pelitic migmatites in Hamedan, Touyserkan and Boroujerd regions, Sanandaj-Sirjan zone

Seyedeh Razieh Jafari

Volume 12, Issue 4 , February 2022, , Pages 51-76

https://doi.org/10.22108/ijp.2022.131054.1255

Abstract

Several outcrops of migmatitic rocks (metatexite to diatexite) developed in the northern part of the Sanandaj-Sirjan zone (Hamedan, Touyserkan and Boroujerd). Two types of inherited ... Read More

Study of mineral chemistry, thermobarometry and petrogenesis of migmatitic rocks of Hamedan area

Ali Asghar Sepahi Gerow; Seyedeh Razieh Jafari; Mohssen Moazzen; Hossein Shahbazi

Volume 9, Issue 1 , June 2018, , Pages 165-190

https://doi.org/10.22108/ijp.2017.103130.1026

Abstract

In the Hamedan region, migmatitic rocks occur with various structures. In the Simin area (South Hamedan) stromatic and in the Darreh-Omar (Toyserkan) area ophtalmitic structures are ... Read More In the Hamedan region, migmatitic rocks occur with various structures. In the Simin area (South Hamedan) stromatic and in the Darreh-Omar (Toyserkan) area ophtalmitic structures are abundant. Migmatites have been developed in a poly-metamorphic region. At least one regional metamorphism and two contact metamorphism by mafic and felsic intrusions occurred in the area. It seems that in the Darreh-Omar area contact metamorphism of mafic body leading to migmatization, But in the Simin area previous regional metamorphism and development of shear zones followed by contact metamorphism by felsic body. Therefore, in some areas, such as the Simin area, the migmatization may have occurred in more than one stage. These are consistent with recent geochronological studies of the Alvand plutonic body and surrounding metamorphic rocks. Index minerals of metapelites such as garnet (almandine), biotite (siderophyllite), staurolite, andalusite, sillimanite, kyanite, fibrolite, cordierite, plagioclase (andesine) and spinel (hercynite) are existing in these rocks. Field geology, petrographic and geochemical evidences suggest that different generations of staurolite, biotite and cordierite exist in metamorphic rocks of different grades in the Hamadan area. These minerals sometimes have been formed by progressive reactions and some other times from retrogressive reactions. A number of these phases have been formed at the peak of metamorphism and some others in later time. Based on thermometric cation-exchange method of garnet-biotite pair, using different calibrations, the obtained temperature using first-generation of biotites is 655 °C and temperature range of 529 °C for second-generation biotites. Cordierite-garnet thermometry indicates a temperature of 637 °C for related migmatitic rocks. In barometry with GPBQ system, calculated pressure for first-generation biotite is estimated to be about 3.9 kbar and for the second-generation biotite around 3.6 kbar.

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Author = Jafari, Seyedeh Razieh

Study of structure and morphology of zircons in pelitic migmatites in Hamedan, Touyserkan and Boroujerd regions, Sanandaj-Sirjan zone

Abstract

Study of mineral chemistry, thermobarometry and petrogenesis of migmatitic rocks of Hamedan area

Abstract