SYN-METAMORPHIC NAPPE COMPLEX IN THE RHODOPE MASSIF - STRUCTURE AND KINEMATICS

Mylonitic gneisses of the Bulgarian and Greek Rhodope were deformed un der medium pressure-type metamorphism. The kinematic information conta ined in these gneisses shows that shear-deformation occurred during de velopment of a nappe complex. Lithologies and metamorphic histories al low a lower (footwall) and an upper (hanging wall) terrane to be disti nguished that define a crustal-scale duplex. As oceanic crust is invol ved, collision between two continental units with subsequent crustal t hickening is inferred. The blocks would be Moesia to the north, and th e Lower-Rhodope promontory to the south, which collided in the Mesozoi c to early Cenozoic. The nappe complex is characterized by south to so uthwestward (foreland directed) piling-up and is associated with both coeval and subsequent extension. The late extension is associated with the establishment of a high temperature-low pressure metamorphic grad ient and plutonism that predates, but makes a transition to, the Litho spheric extension of the Aegean Arc.