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.