EVIDENCE FOR A DUALITY OF THE HELLENIC TRIASSIC VOLCANISM - CONTRIBUTION OF TRACE-ELEMENT GEOCHEMISTRY

Petrological and geochemical studies on Othrys lavas from the Maliac zone (internal zones) and on Vardoussia lavas from the eastern border of the Pindos-Olonos zone (external zones) show evidence for two distinct Triassic volcanism suites in the Hellenides. Othrys lavas are of anorogenic type. They present typical features of the more or less enriched MORB type tholeiitic suites. On the other hand Vardoussia lavas belong to an orogenic calc-alkaline suite. Consequently, most of the geodynamic models explaining the Triassic Hellenic volcanism only with subduction zones need to be modified. The models have to take into account the anorogenic character of some of the lavas (e.g.: in the Maliac zone of Othrys).