Chemical composition-of the actinolite-hornblende assemblage as indicator for the P-T metamorphic conditions in chlorite-amphibole schits and metadiabases Vrteska, Plackovloa Mt, Eastern Macedonia

Microscopic and electronic microprobe studies carried out on the chlorite - amphibole schists and the metadiabases from the vicinity of Vrteska determined an actionolite, Mg - hornblende, biotite, epidote, chorite, albite, quartz, and ilmenite assemblage. The metamorphic mineral assemblage andstructural - textural characteristics indicate that these rocks metamorphosed in conditions of regional dynamothermal metamorphism in a Berovian type series of facies which, according to the degree of metamorphism, corresponds to the transition from quartz-albite-epidote-biotite to quartz-albite-epidote-almnedine subfacies. The chemical composition of actinolite and hornblende indicate that the rock under investigation metamorphosed in conditions of prograde metamorphism at T - 400-500 C and P -2-5 kbar.