The Paleogene history of the Pelagonian zone s. l. (Hellenides, Greece): Heavy mineral study from terrigenous flysch sediments

The terrigenous material of the flysch of the Pelagonian Zone s.l. of the I nternal Hellenides in Pelion, Skopelos, Euboea, Othrys Mountain and Argolis have been characterized by their heavy mineral assemblages, based on 114 s amples. The terrigenous input can be divided into a garnet-dominated associ ation, restricted to flysch sediments of bath western Othrys and Ligourion (Argolis), and assemblages with variable amounts of the stable ZTR group (z ircon, tourmaline, rutile) and apatite, found at all the other localities. The garnet assemblage is assumed to have been derived from mica schist comp lexes existing at the western margin of the Pelagonian microcontinent, tect onically active due to the closure of the Pindos Ocean. The situation is si milar to that already known from the Pindos and Parnassos-Ghiona zones. Blu e amphiboles detected in western Othrys witness the existence of blueschist terrains. The ZTR-apatite group points to a different source province, not connected regionally with the former source. The activity of this source t errain can be related to the closure of a Neotethyan ocean in the Vardar Zo ne, along the eastern margin of the Pelagonian Unit, during the early Terti ary. The heavy mineral assemblages indicate that in this source area ophiol itic complexes are tectonically incorporated to a lesser extent. Blueschist s seem to be absent, as no detrital blue amphibole was found.