U/Pb analyses of 595 zircons from 10 samples yielded more than 500 pre-Carboniferous ages (Table 1 - See Appendix A.). The samples included metasediments from the Hellenic forearc in Kythera, Peloponnese and Crete, and from the Hellenic volcanic arc from Milos, and Santorini (Fig. 2). Pre-Carboniferous ages (n=502) were derived from all the detrital zircons in metasediments from the forearc and volcanic arc. Post-Carboniferous U-Pb ages (n=33) were less abundant, and completely absent from the Peloponnese detrital samples. Blueschist facies rocks from Milos yielded Carboniferous and Late Cretaceous zircons and along with some inherited cores of pre-Carboniferous events.

A total of 534 zircon grains out of the 595 grains are less than 10 percent discordant. These concordant zircons show a wide range of ages that when pooled reveal populations at ca. 60-80 Ma, 180-220 Ma, 300-360 Ma, 500-570 Ma, 600-680 Ma, 900-1100 Ma, ~ 2 Ga, 2.5 Ga, and 3.3 Ga (Fig. 4). A summary of major zircon age populations along with major Phanerozoic and Precambrian events is graphically displayed in Figure 5. The main populations are all defined by more than 35 individual analysis; ages younger than 650 Ma compose almost half (n=218) of the total number of analyses. The most prominent peaks from the combined analyses are also the youngest due probably to the better preservation potential of younger zircons with less radiation damage. Populations correspond to the Cyclades high grade metamorphism ~ 80-60 Ma, the Triassic igneous event (220-180 Ma; Finger et al., 2002; Romano et al., 2004), the Variscan igneous event (350-320 Ma; Keay et al., 2001; Keay & Lister, 2002; Xypolias, 2006), the PanAfrican Orogen (640-540 Ma; e.g. Nance and Murphy, 1994) the Grenvillian-aged orogenetic belts (1.1-0.9 Ga; e.g. Dalziel, 1997; Kemp et al., 2006; Mueller et al. 2008), the Icartian-Eburnian crust formation event that is known from the West African Craton (~ 2 Ga; e.g., Ennih and Liegeois, 2001; Egal et al., 2002; Walsh et al., 2002). There is smaller population of early Paleoproterozoic and NeoArchean zircon centered at about 2.5 Ga. The four oldest zircons give concordant Paleoarchean ages of 3134 ±9.4 Ma, 3264 ±9.4 Ma, 3416 ±9.4 Ma, 3487 ±9.5 Ma and are all from a metasedimentary unit sampled from the upper plate of the detachment fault in Kythera.

There are three distinctive gaps in the zircon age populations that occur between the main peaks: these include no grains with early Mesoproterozoic (~1350-1646 Ma), middle Paleoproteroizoic (~ 2151-2429 Ma), and Mesoarchean (~ 2828-3134 Ma) U-Pb ages.