Abstract
We have investigated subduction-exhumation processes in the Pelagonian zone, exposed on the Northern Sporades islands (Aegean Sea) related to successive episodes of ocean continent and continent-continent convergence through integrating multiscale structural analysis, metamorphic petrology, and white mica 40Ar/39Ar dating. Two major progressive phases of ductile deformation are documented, which are related to distinct episodes of tectonic burial and exhumation of the Pelagonian continental margin, which was facing the Neotethys/Vardar ocean. Review of existing data sets from neighboring regions shows that both deformation phases can be correlated along strike up to the Dinarides. The first phase of tectonic burial and exhumation (D1) is characterized by NW-SE tectonic transport, greenschist facies metamorphism, and Early Cretaceous (~105-135Ma) 40Ar/39 Ar white mica single fusion ages. D1 is correlated with the initial closure of the Vardar ocean by top-to-the-W to NW ophiolite obduction and the underthrusting of the Pelagonian margin below the oceanic upper plate. Underthrusting was followed by exhumation and the deposition of Late Cretaceous-Paleogene sediments. The second phase of burial and exhumation (D2) is characterized by NE-SW tectonic transport, greenschist to blueschist facies metamorphism, and latest Cretaceous-Early Eocene 40Ar/39 Ar white mica ages of S2 fabrics. Top-to-the-SW shearing is correlated with the tectonic burial of the Pelagonian zone below the Eurasian continent (Rhodopia), while top-to-the-NE shearing is attributed to subsequent extensional exhumation. D2 fabrics record low-grade P-T conditions suggesting that the decoupled cover formations exposed on Skopelos were incorporated in an accretionary wedge that formed above the subducting Pelagonian basement during Paleogene times.
Original language | English |
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Pages (from-to) | 1946-1973 |
Number of pages | 28 |
Journal | Tectonics |
Volume | 38 |
Issue number | 6 |
Early online date | 21 May 2019 |
DOIs | |
Publication status | Published - Jun 2019 |
Funding
The research leading to these results has received funding from the European Union's MSCA‐ITN‐ETN Project SUBITOP 674899. 40Ar/39Ar dating was performed in collaboration with the VU University Amsterdam, while pressure‐temperature calcula tions and microprobe analysis in colla boration with the National and Kapodistrian University of Athens. We thank to the reviewers and editors for substantially improving our manuscript with their constructive remarks. We also thank to Evangelos Moulas for his helpful advices regarding pressure‐ temperature calculations and Jean‐ Pierre Brun for fruitful discussions on the Aegean geology. The data support ing this paper are available from the Utrecht University Tectonics database via uu.teclab@gmail.com.
Funders | Funder number |
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Utrecht University Tectonics | |
Horizon 2020 Framework Programme | 674899 |
European Commission | |
Vrije Universiteit Amsterdam | |
National and Kapodistrian University of Athens |
Keywords
- Ar/Ar dating
- continental underthrusting
- kinematic analysis
- Pelagonian
- Skopelos
- successive burial-exhumation cycles