全球变化知识资源中心

The synmetamorphic nappe system of the Rhodope Metamorphic Complex has been deformed into dome-and-basin structures attributed to syn- to post-convergent exhumation. We document the deformation style and present new thermobarometric and geochronological constraints for the Kesebir–Kardamos dome in southern Bulgaria and northern Greece. The dome consists of a migmatitic core overlain by high-grade thrust sheets. Kinematic indicators indicate a continuum from ductile to brittle conditions during exhumation. Thermodynamic modeling applied to the high-grade, intermediate thrust sheets yielded peak conditions of 1.2 GPa and ca 730 °C. New U–Pb SHRIMP-II dating of zircons from rocks of the same unit revealed Late Jurassic–Early Cretaceous (145 Ma) as the time of metamorphic crystallization; some zircon rims yielded Eocene ages (53 and 44 Ma) interpreted as having been thermally reset owing to coeval granitoid magmatism. The high-grade rocks were covered by Lutetian–Priabonian marine sediments after exhumation. Slumps suggest that sedimentation took place in a tectonically active environment. Our new structural, petrological and geochronological results suggest that the major shear zone in the core of the Kesebir-Kardamos dome is equivalent to the Late Jurassic–Early Cretaceous Nestos Shear Zone. Post-Jurassic metamorphic ages recorded in the Rhodope most likely represent crustal rather than deep subduction geodynamic processes. © 2017, Springer-Verlag Berlin Heidelberg.