INTRACONTINENTAL WEDGING AND POSTOROGENIC COLLAPSE IN THE MESOHELLENIC TROUGH

The Mesohellenic Trough is a 130 km long and about 30 km wide subsidin g area which contains a thick sequence of well exposed Late Cenozoic p ost-orogenic sediments. This intermontane basin, located at the contac t between the Apulian and Pelagonian collided margins, provides a good example of the characteristics needed to study the chronology of late orogenic intracontinental structures. The Mesohellenic Trough was dev eloped from the Middle Eocene to Middle Miocene as a piggy-back basin along the eastern flanks of a giant pop-up structure. This structure c onsists of west-verging, foreland-propagating thrusts within the Apuli an plate and of east-verging backthrusts within the Pelagonian plate. As a result the eastern parts of the Apulian margin were thickened and uplifted, followed by post-orogenic collapse. Internal deformation of the sedimentary infill varies widely along the trough axis. At the no rthern and southern terminations of the trough, two small indentors in duced a tectonic escape towards the central part of the basin until th e Middle Miocene. During this process of convergent wrenching, 'revers e strike-slip faults' and 'pure strike-slip faults' formed. Towards th e central part of the trough, convergent wrenching decreased gradually until it was replaced by a post-orogenic collapse with normal and obl ique normal faults trending parallel and/or perpendicular to the troug h axis.