| heal.abstract |
The Palaeogene-Early Miocene geodynamic evolution of the Hellenides is characterised by widespread flysch deposition. In the Pelagonian, Parnassos-Ghiona and Pindos Zones, flysch sedimentation commenced during the Maastrichtian-Palaeocene and lasted until the Eocene, but in the northern Pindos Zone it continued until the Oligocene, and in the Ionian and Gavrovo-Tripolitza Zones, flysch deposition lasted from the Late Eocene to the Early Miocene. During the Maastrichtian-Palaeocene, two source terrains supplied the Pelagonian flysch basin. In the eastern parts the stable heavy mineral group (zircon, tourmaline, rutile and apatite) predominates, while in the western margin a tectonic wedge, generated by the subduction of the Pindos Ocean, shed garnet and glaucophane to western parts of the Pelagonian basin, and also to the Pindos and Parnassos flysch. The appearance of detrital glaucophane (which shows a chemical affinity to Cycladic blue amphiboles) in Palaeocene sediments reveals the exhumation of blueschist facies rocks which underwent metamorphism during the Late Cretaceous. The stratigraphically younger parts of the Pindos flysch (Middle Eocene to Late Oligocene) show a considerable increase in abundance of the stable minerals and ophiolite detritus. In the Late Eocene, the internal flysch basins were tectonically incorporated into a nappe pile with the Pindos nappe in front. The resulting crustal loading led to the formation of a foreland basin and deposition of sediments in the Gavrovo-Tripolitza and the Ionian Zones. The reworking of Pindos flysch occurred during progradation of the nappe pile. Stable heavy minerals and ophiolite detritus, typical of the higher stratigraphic successions of the Pindos flysch, have been found in the eastern parts of the Gavrovo-Tripolitza Zone, exposed only in the Peloponnese, while the western parts in the Peloponnese, the mainland and the Ionian Zone are characterised by garnet-dominated assemblages accompanied by glaucophane, derived possibly from lower sections of the Pindos flysch. Heavy mineral assemblages of the meta-flysch in the tectonic windows of Olympos and Ossa are comparable with those from the eastern Gavrovo-Tripolitza Zone. © 2007 Elsevier B.V. All rights reserved. |
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