Conclusion
Both stratigraphic ages of the sedimentary cover and radiometric dating of crystalline rocks substantiate synmetamorphic thrusting and exhumation in Early Cretaceous times, and additional extensional exhumation in two steps starting with the Late Eocene transgression.
The imbricate units represent an Alpine suture zone in which remnants of a partially subducted magmatic arc, foundered on the attenuated margin of Europe, are preserved. Subduction and collision of the arc with the incoming Lower-Terrane continent produced decoupling within the arc and subduction of its deeper parts along with the frontal parts of the Lower Terrane, one of the intra-Tethys continental blocks derived from Gondwana. This is when the complex north-dipping stack of syn-metamorphic nappes developed in the Rhodope. Imbrication involved crustal extrusion that generated east-northeast-verging, flat-lying and synmetamorphic shear zones coeval with, and as a consequence of, terminal continental collision. Gravitational collapse contributed to lateral spreading of the upward rising high-grade terranes.
Another extensional episode started in the early Eocene in the Rhodope, 10–15-Ma earlier than in the Cyclades and might be due to mantle delamination. Aegean extension, which started in the Miocene, is still shaping the geology of the Rhodope Metamorphic Complex.