GRANITOID ROCKS OF NAXOS, GREECE - REGIONAL GEOLOGY AND PETROLOGY

Granitic gneiss in a Miocene extensional core complex on Naxos locally preserves primary igneous textures. On an outcrop scale, these includ e mafic enclaves; in thin section, feldspar phenocrysts contain unorie nted accessory mineral inclusions. The gneiss is interpreted as having a Hercynian granite protolith. Contrary to previous accounts, migmati tes are rare in the gneiss. The granite is geochemically similar to po st-collisional extension-related granites and differs from the predomi nant granodiorites found in the Hercynian basement of northwestern Gre ece. An I-type hornblende-biotite granite pluton was emplaced during M iocene extension in western Naxos. It is a typical subduction-related pluton emplaced under conditions of back-are extension. The pluton is cut by later leucogranite that geochemically resembles the granite dyk es that cut the migmatites. In northern Naxos, minor leucogranite intr usions are of two geochemical types. One is everywhere deformed and ge ochemically resembles the leucogranite that cuts the Western pluton. T he other is variably deformed and new geochronology shows that it has an age of 10 Ma. (C) 1997 by John Wiley & Sons, Ltd.