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Metamorphic And Tectonic Evolution Of The Hırkadağ Block, Central Anatolian Crystalline Complex, Donna L. Whitney, Yildirim Di̇lek

Turkish Journal of Earth Sciences

The Hırkadağ metamorphic block is a NE-SW-trending horst structure that is part of the Kırşehir Massif in the Central Anatolian Crystalline Complex (CACC). Along its southwestern margin, the block contains upper amphibolite facies metapelitic rocks that record peak metamorphic conditions of 670-710 °C, ~ 7 kbar, as determined by garnet-biotite geothermometry and garnet-sillimanite-plagioclase-quartz, garnet-rutile-sillimanite-ilmenite-quartz, and garnet-rutile-ilmenite-plagioclase-quartz geobarometry. A clockwise pressure-temperature path is inferred from thermobarometric results and analysis of reaction textures among aluminous phases. Following this medium-pressure metamorphism, low-pressure - high-temperature metamorphism resulted in widespread replacement of garnet by cordierite + spinel + sillimanite, partial replacement of spinel by corundum, …