HIGH-PRESSURE METAMORPHISM AND COOLING ON SE NAXOS (CYCLADES, GREECE)

The island of Naxos, in the centre of the Aegean Sea, is a Cordillera- type metamorphic core complex formed by the collapse of the Alpine oro genic belt of the Hellenides. The island is dominated by Early-Miocene (M2) Barrovian metamorphic assemblages that overprinted Eocene (M1) h igh-pressure (HP) rocks. A P-T path, which integrates data from a new, unique occurrence of jadeite-bearing blueschists, shows that the rock s of SE Naxos near the top of the lower plate sequence reached MI P-T conditions of at least 12 kbar and ca. 470 degrees C, and then cooled during decompression. This P-T path strongly differs from P-T paths re corded in the lower part of the section exposed in central Naxos, wher e M2 healing caused migmatization and anatexis and completely oblitera ted the high-pressure mineral assemblages. It is postulated that the c ontrasting P-T paths on Naxos reflect the effect of heat launched from below the section and cooling caused by unroofing and denudation of t he section from above.