Relative contributions of crust and mantle to generation of Oligo-Miocene medium-K calc-alkaline I-type granitoids in a subduction setting—a case study from the Nabar Pluton, central Iran

The Nabar pluton with the age of Oligo-Miocene located northwest of Isfahan, the Urumieh-Dokhtar magmatic belt, is composed of gabbro, gabbro diorite, diorite, quartz diorite, tonalite, and quartz monzonite. These rocks contain plagioclase, quartz, alkali-feldspar, magnesiohornblende, actinolite, tremolite-hornblende, actinolite-hornblende, anthophyllite, biotite, and Na-poor pyroxene. Application of the Al-in-hornblende barometry indicates pressures of 2–2.15 kbar, whereas the clinopyroxene barometry shows a pressure of 5 kbar. The temperature (i.e., 750–800°C) is estimated using the amphibole-clinopyroxene thermometry in a dioritic sample. Magmatic water content was greater than 10% at the time of formation of dioritic rocks in the Nabar pluton.