TRANSPRESSION AND TRANSTENSION WITHIN DIFFERENT STRUCTURAL LEVELS IN THE CENTRAL AEGEAN REGION

In the central Aegean region, shortening structures within the Miocene molasse are known since long ago. Nevertheless recently, most authors have recognized extensional structures within Middle to Upper Miocene granitoids, proposing a Basin and Range type model for the Late Cenozoic evolution of the area. To resolve this problem, structural mapping and mesoscopic analysis of 900 faults sampled from 12 islands have been carried out. Late orogenic uplift of the central Aegean region is the result of a continuous convergence and indentation of the Pelagonian plate by the Apulian plate, that took place throughout the Miocene. Formation of core-complexes can be associated with: (a) large oblique-upthrusts, (b) steeply dipping strike-slip faults, and (c) low-angle normal faults. The latter are produced by low, multidirectional extension, which has affected small crustal regions as adjacent areas underwent transpression. In the late stages of collision the overthickened crust began to collapse due to transtension which was replaced by extension caused by the roll-back of the Hellenic subduction zone in the Lower Pliocene time. This extensional regime has lasted until the present day.