Petrography, mineral chemistry and P-T estimation of pelitic schists from north of Golpayegan, Isfahan province

The Muth-Golpayegan metamorphic complex is situated at north of Golpayegan city in the Isfahan province. This complex is constituted from different metamorphic rocks including variety of pelitic schists, amphibolite, gneiss, quartzite and marble. Garnet schists are dominant lithology in the area and contain different minerals, such as garnet, quartz, chlorite, muscovite, biotite, staurolite, andalusite, kyanite and sillimanite. Lepidoblastic, porphyroblastic, poikiloblastic, augen and millipede are the main textures in these rocks. The degree of metamorphism increases from SW to NE in a way that slate and phyllite at SW change gradually to chlorite schist, biotite schist, garnet schist, staurolite schist, sillimanite schist and kyanite schist. The occurrence of these schists is accompanied by appearance of chlorite, biotite, garnet, staurolite, sillimanite and kyanite mineralogical zones in the field. The succession of these zones is compatible with Barrovian regional metamorphic gradient. Chlorite, biotite and garnet zones belong to the greenschist facies and staurolite, sillimanite and kyanite zones belong to the amphibolite facies. Temperature range calculated for these rocks by garnet-biotite thermometry is 471-581 C. This metamorphic gradient is a result of continental collision.