REGIONAL METAMORPHISM OF THE DETRITIC ROCKS IN ORTAKÖY (AKSARAY) AREA

Abstract

The detritic rocks of Ortaköy area were undergone a regional metamorphism which caused development of the paragenesis: sillimanite + plagioclase (An 0.43) + orthoclase + quartz + biotite (Ann 0.08, Phl0.012) + garnet (Alm 0.80-0.83, prP 0.10- 0.08 Sp 0.048-047 Grs 0.048-0.045).By geothermobarometers of garnet-biotite and garnet-aliiminosilicate-quartz-plagioclase, the regional metamorphism conditions were determined as P= 3.3±0,36 kb and T=~600°C. The garnet has inverse mineralogical zoning due to homogenisation or exchange reaction between garnet and matrix. Decreasing of grossulerite content in the garnet towards its rim, and occurence of andalusite, chlorite and sericite show that P-T conditions in Ortaköy area follows a clockwise path in P-T-t trajectory.