P-T pattern of eclogite formation of the Shafarud Metamorphic Complex in the Talesh subzone, NW Iran using zoned garnets

The Shafarud Metamorphic Complex is located in the northwestern part of Iran in the Alborz-Talesh Mountain range. Paleozoic metamorphism (Carboniferous-Permian) are the oldest rocks of this region. The eclogites of the Shafarud Metamorphic Complex are exposed as lenses of several meters in size along with serpentinite masses in the basal parts. The mineral assemblage of the eclogites includes garnet, pyroxene, amphibole, white mica, epidote, plagioclase, chlorite, quartz and sphene. SEM images and the results of electron probe micro-analyzer (EPMA) show the growth chemical zoning in garnet porphyroblasts. According to the calculation of the temperature-pressure pattern, using Jacobian transformation, the core and the rim of garnets have been formed respectively at temperature-pressure 600 ºC -18.2 Kbar (eclogite facies, ~60 Km) and 550 ºC- 7.5 Kbar (green schist facies, ~25 Km). According to the results of this study, the structural pattern of the eclogites of the Shafarud Metamorphic Complex is similar to the alpine type, during which the process of uplift and pressure reduction occurred in almost isothermal conditions due to a rapid uplift.