ORIGIN OF THE ANTIPAROS ISLAND RHYOLITES, GREECE, BY SUBDUCTION-RELATED ANATEXIS OF A GRANULITIC SOURCE POSSIBLY LOCATED IN THE MIDDLE TO LOWER CONTINENTAL CRUST
The high-silica Pliocene rhyolites of the Antiparos island, which is located about 50 km north of the central part of the South Aegean volcanic arc in Greece, have relatively high K and Na contents, are significantly enriched in Rb, Cs, U, Th and Nb and extremely depleted in Ba and Sr. According to the proposed model the rise of hot basic magma, generated by the subduction of the Aegean oceanic slab, near the base of the continental crust underneath Antiparos incited the partial melting of a felsic granulite source possibly located in the middle to lower crust. Subsequently the primary magmas rose to a shallow magma chamber where they evolved by significant fractional crystallisation involving dominant alkali-feldspar and subordinate Ab-rich plagioclase, quartz, titanite and hornblende.
KEY WORDS: rhyolite; continental crust anatexis; subduction; Antiparos; Greece.