Writers : Keshtkar, E.; Gharishvandi, H.; Ghorbani, M.; Masoodi, F.
Refference : The Forth National Geological Conference of Payam Noor University(PNU)
Publishing Year : 1389

Abstract :

The metamorphic rocks of the southwest Gayen, with the age of proterozoic located next to a complex of sedimentary and garnitoide rocks in east Iranian micro-continent. Based on the petrographic studies and field observations, the most important metamorphic rocks of the area, include slate, mylonite, gneiss and migmatite. The major rock- forming minerals of the gneisses are alkali feldespats, quartz, biotite, plagioclase, muscovite and amphibole, and among its accessory minerals, zircon, sphene, apatite, epidote and Fe- oxides can be mentioned. The most common textures of the gneisses are granoblastic and lepidoblastic. The presence of granular texture, automorph grains of zircon and sphene, K-feldspats megacrysts and finally, are evidence for the igneous origin of the mentioned rocks. Moreover, based over MgO/CaO diagram compared with P2O5/TiO2 and Shaw΄s average diagram and similarity of rare element, with metamorphic rock it can be concluded that the studied gneisses in the area, have been formed from metamorphism of the igneous rocks during a dynamothermal phase (probably in the middle Cimerian orogeny).

Subject List : petrography