Geothermobarometry of Cheshme-Bid Granitoids Based on mineral Chemistry Classification, southeast of Iran

The Cheshme-Bid Granitoids is located in SE Zahedan, Sistan and Balouchestan P Province. These granitoids are in Middle Eocene Neh metamorphosed flysch zone. The main minerals in these granites are quartz, plagioclase, biotite and amphiboles. Based on microprobe analysis, amphiboles are calcic in composition and set on magnesio-hornblende and actinolite classes. Based on chemical classification of micas, these minerals are located between siderophyllite and biotite. The Fe/(Fe + Mg) > 0.33 ratio shows that mica minerals are biotites and they are separated from phlogopites. The composition of plagioclase is between 19.56 to 32.51 An and the average of anorthite is 23.78 %. Estimated pressure and temperature for the formation of the granitoid, based on Al- Barometry in hornblendes, is about 3.8 Kb and the temperature is relatively low, about 751 celsius degree in granodiorite.