Deformation phases and ophiolites emplacement in the Hellenides

The terms ophiolites, ophiolite nappes and ophiolite bearing sedimentary formations in Greece, refer to outcrops of mainly peridotites, but also of basaltic rocks with eventual sedimentary formations. Based on the present-day scientific knowledge, the ophiolites as a whole are characterized by high variability regarding: a) their petrological signature, from their petrography, their mineral chemistry up to their alterations, b) their deformation pattern ranging from plastic to brittle, including both compression and extension phases, c) their emplacement characteristics, involving extensive nappes, lithostratigraphic alternations and melanges. Detailed analysis of a large number of ophiolite outcrops demonstrated their occurrence in different geotectonic conditions (tectonic windows, nappes and clastic sedimentary complexes), in variable geometric forms (isolated bodies, lenses and interlayers), in various composition and deformation configurations (harzburgites, lherzolites, metagabbros and amphibolites, basalts and sedimentary formations). The ophiolites experienced a continuous deformation from the Late Jurrasic phase (EoHellenic) up to the Eocene-Oligocene alpine orogeny (HoHellenic). Their evolution involved different emplacement mechanisms, producing a significant thickening in the oceanic and the surrounding environments and an extensive thinning in the continental margin environment.