Metamorphic conditions and structural evolution of the Kesebir-Kardamos dome: Rhodope metamorphic complex (Greece-Bulgaria)

Abstract

tel: +41 44 632 21 15 Acknowledgements E.M. would like to acknowledge the Alexander S. Onassis Public Benefit Foundation and the ERC starting grant (335577) for financial support. We would also like to acknowledge ETH-Zurich for covering fieldwork and analytical expenses. The scientific staff of the Center of Isotopic Research (CIR) at VSEGEI, St. Petersburg (Russian Federation) is acknowledged for their help during E.M.'s stay at St. Petersburg. Jan Pleuger is acknowledged for discussions regarding the geology of Rhodope. Lucie Tajčmanová, James Connolly, Konstantinos Kydonakis and Torgeir Andersen are acknowledged for comments on an earlier version of the manuscript. Constructive reviews by N. Georgiev, A. Kounov, Ingo Braun and editorial handling by Prof. Wolf-Christian Dullo are highly appreciated. Abstract 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 1.2GPa and ca 730°C. New U-Pb SHRIMP-II dating of zircons from rocks of the same unit revealed Late Jurassic-Early Cretaceous (145Ma) as the time of metamorphic crystallization; some zircon rims yielded Eocene ages (53 and 44Ma) 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.

Tectonic units of the Alpine collision zone between Eastern Alps and western Turkey

“…We included the following units into the Rhodope middle unit (see Fig. 10 for the locations of these units): Variegated series found rimming dome-like structures in the northwestern part of the Rhodope lower unit in the Pirin Mountains (Georgiev et al, 2010), the Mesta and Slashten sub-units located southeast of the Pirin Mountains (Sarov et al, 2008;Froitzheim et al, 2014), the Malyovitsa sub-unit in the area upstream from Rila monastery (Gorinova et al, 2019), the Chepelare shear zone (Petrik et al, 2016a), the Starcevo and Borovitsa sub-units (Pleuger et al, 2011), and finally, the Krumovitsa and Kimi sub-units in southeastern Bulgaria and adjacent Greece rimming the Kesebir-Kardamos dome (Mposkos and Krohe, 2006;Bonev and Stampfli, 2011;Georgiev et al, 2016;Moulas et al, 2017).…”

Fingerprinting Paranesti Rubies through Oxygen Isotopes

“…Geological map of the Rhodope Mountain Complex, with Paranesti located within the Nestos Shear Zone (red star) (Adapted from Moulas et al, 2017[17]). …”

Mineralogical Characterization of Early Bronze Age Pottery from the Svilengrad-Brantiite Site, Southeastern Bulgaria

“…The relatively high-grade metamorphic rocks at the Sakar Mountain area are very similar to the basement and metamorphic rocks in the Eastern Rhodope massif [18]. These geological bodies differ, however, in their maximum pressure conditions during metamorphism: ~8 k bar for Sakar Mountain [21,35] and ~13 k bar for the Rhodope massif [27,29,36,37]. Thus, the chemical compositions of their rock-forming minerals may also slightly differ.…”