Extensional tectonics in Mt Parnon (Peloponnesus, Greece)

Peloponnesus in the south-western part of the Aegean is formed by a heterogeneous pile of alpine thrust sheets that was reworked by normal faulting from Upper Miocene to recent times. Upper Miocene-Lower Pliocene extension in Mt Parnon was accommodated by several mappable brittle detachment faults that exhibit a top-to-the-NE-ENE sense of shear. The hanging wall of the detachments comprises a number of highly tilted fault blocks containing abundant evidence of intense internal deformation by normal faulting and layer-parallel shearing contemporaneous with faulting. These fault blocks are remnants of a cohesive extensional block that slipped to the NE-ENE and broke up along high-angle normal faults that sole into or are cut by the detachments. The largest part of this block is located at the eastern edge of the metamorphic core forming the hanging wall of East Parnon high-angle normal fault that excised part of the aforementioned detachments. The lowermost metamorphic Unit of the nappe-pile does not seem to be affected by the previous extensional episode. Upper plate reconstruction shows that various units of the nappe-pile were affected by high-angle normal faults that linked to detachment faults in the weaker layers. Since the Middle-Upper Pliocene further exhumation of the metamorphic rocks has resulted in the formation of high-angle normal faults overprinting Neogene extensional structures and cut the entire nappe-pile. This new fault system tilted the earlier extensional structures and produced a NE-SW coaxial deformation of Mt Parnon.