Petrogenesis of Soheyle- Pakuh and Golshekanan granitoid based on mineral chemistry of ferromagnesian minerals (north of Nain), Iran

作者：Esfahani Mahin Mansouri^*; Khalili Mahmoud; Bakhshi Mohammad

来源：Journal of African Earth Sciences, 2017, 129: 973-986.

DOI：10.1016/j.jafrearsci.2017.01.033

• SPGG
• Ferromagnesian minerals
• I-type granitoid
• Urumieh-Dokhtar
• Iran

The Middle Oligocene I-Type Soheyle- Pakuh and Golshekanan granitoid (SPGG) occurs in Urumieh-Dokhtar magmatic belt and north of Nain in central part of Iran. The dominant studied intrusive rocks are diorite, quartz-diorite, tonalite, granodiorite and granite which petrographically are characterized by the presence of plagioclase, quartz, K-feldspar, amphibole, pyroxene, biotite, apatite, titanite, zircon, tourmaline, allanite and opaques. The pyroxenes comprise calc-alkaline augite, calcic amphiboles and Fe rich biotite. Using Fe2+/Fe2++Mg and Al ((tot)) for primary amphiboles, an average pressure of 2 Kbar was estimated corresponding to the depth of between 3.63 and 10.88 km. Further, the low Na2O and TiO2 contents of these phases suggest subduction environment (S-Amph). Distribution of aluminum in clinopyroxenes suggests that these minerals formed at <5 lobar pressure and their water content was between 5 to over 10 percent. Biotites from gabbroic diorite, diorite and tonalite, using Ti and Mg/Mg + Fe diagram, crystallized at temperature of about 720 degrees C whereas, the pyroxenes and enclaves solidified in the range of 1100-1175 degrees C. The overall geochemical data suggests that the SPGG are high temperature, I- type, calc-alkaline developed in high oxygen fugacity in an orogenic tectonic setting related to volcanic arc environment consistent with the subduction of Neotethys oceanic underneath the Central Iranian microcontinent during Upper Cretaceous to Paleogene.

• 出版日期2017-5