Tectonometamorphic evolution of the Western Rhodope complex - a record of multiple continent collision?

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The Rhodope Complex in Bulgaria and Greece represents a stack of metamorphic thrust nappes recording a long history of Alpine orogenic deformation from Jurassic to present, including periods of thrusting and of extensional shearing and faulting. Previous work suggested that high- and ultrahigh-pressure metamorphism occurred at several times during the Alpine cycle (Jurassic, Cretaceous, and Tertiary). Our working hypothesis is that these metamorphic events resulted from multiple collisions of microcontinents, and that the exhumation of the high- and ultrahigh-pressure rocks resulted from processes inherent in multiple continent collision. We intend to study the kinematics, timing, and plate tectonic setting of these events by analysing the structural and metamorphic evolution of the western Rhodope complex (Rila, Pirin, West Rhodopes) in Bulgaria and Greece, using a combination of field mapping, kinematic analysis of shear zones (structures, microstructures and textures), metamorphic petrology (P-T-determi nation), and geochronology (U-Pb SHRIMP dating of zircon). The study area in the western part of the Rhodope complex is ideally suited for investigating the effects of multiple continent collision because of the presence of important shear zones, both compressional and extensional, of ophiolitic sutures, of pre-, syn- and posttectonic granitoid intrusions allowing to date the shear zones, and of Tertiary, detachment-related basins whose position and sediment fill record the late stages of extensional deformation and the unroofing of the metamorphic complexes.