Zircon in amphibolites from Naxos, Aegean Sea, Greece: origin, significance and tectonic setting

摘要: We report U–Pb zircon ages of c. 700–550 Ma, 262–220 Ma, 47–38 Ma and 15–14 Ma from amphibolites on Naxos Island in the Aegean extensional province Greece. The has complex internal structures. Based cathodoluminescence response, zoning crosscutting relationships a minimum four growth stages are identified: inherited core, magmatic inner metamorphic (?) rim an outer rim. Trace element compositions suggest igneous differentiation crustal assimilation. Zircon solubility as function saturation temperatures, Zr content melt composition indicates that did not originally crystallize mafic bodies but was felsic precursor rocks, subsequently assimilated into intrusives during emplacement. inheritance is corroborated by complex, xenocrystic nature one sample. Ages 700–550 Ma 262–220 Ma assigned to zircon. Available geochemical data rims grew in situ amphibolites, corresponding high-grade event at this time. However, cannot conclusively establish if 40 Ma also in situ, or whether they were along with cores. Two scenarios for emplacement discussed: (i) Intrusion late-Triassic Jurassic ocean basin development realm, which case would have grown (ii) Miocene result underplating large-scale extension. In case, only formed amphibolitic host rocks.