OROGENIC EVOLUTION OF THE HELLENIDES - NEW ASPECTS

This progress report is based on investigations of the tectonometamorp hic development of crystalline complexes and is restricted to a few ke y problems of the Hellenides: 1. 'Hinterland'. Rhodopia is strongly af fected by Alpidic metamorphism, granitoid intrusions, orogenic deforma tion and intracrustal delamination. Therefore, close relations between the Balkanides and Hellenides have to be considered. 2. External zone s. The Phyllite-Quartzite Series probably originated in a Late Palaeoz oic rift within Apulia. In Middle Triassic times rifting stopped and t he area became the basement on an extended carbonate platform (Late Tr iassic-Liassic). From the Dogger to Palaeocene, parts of that platform subsided, forming the Ionian pelagic basin. The Eocene orogenesis wit hin the central Hellenides then caused an inversion of the buried Phyl lite-Quartzite rift zone, whereas from the Late Oligocene onwards the previous rift zone underwent continental (A-) subduction. Finally, upl ift of the Phyllite-Quartzite Series and nappe emplacement started in Miocene times. 3. Late orogenic intracrustal shearing. Structural anal yses of crystalline complexes of Attica have shown that neotectonic ex tension and the large vertical displacement of the Aegean region were caused by low angle faulting and large-scale.shearing within the deepe r crust, probably along former overthrust planes. These results reveal the mechanisms of intracratonic tectonics, remobilization of continen tal crust and intracrustal detachment throughout the evolution of the Hellenides.