Geothermobarometry of granitoids from Torud-Chah shirin area (south Damghan)

Granitoid bodies of south of Damghan with northeast- southwest trend have intruded into the Eocene volcanic,volcanoclastic and Cretaceous carbonate deposits. Recent studies have revealed that the Al content of hornblende in calc-alkaline granitoids varies linearly with pressure of crystallization, thereby providing a mean of determining depth of pluton emplacement. Based on results of electron microprobe analyses, amphibole minerals present in these bodies, according to Leake are ploted in the field of calcic amphiboles and show Actinolite, Actinolite-Hornblende and Magnesio hornblende composition.Calculated pressures of emplacement, using the Al-content of Hornblende, for these bodies ranging from about 0.51 to 0.98 Kbar (about depth of 1.8 to 3.5 Km). The altimate equilibration temperatures of minerals were calculated using different thermometers ranging from 613 to 772 oC.