EGU21-13393, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-13393
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Subduction and roll-back of narrow oceanic slabs: Back-arc basin modelling of the Carpathians subduction zone

István Bozsó1,2, Ylona van Dinther1, Liviu Matenco1, Attila Balázs3, and István Kovács4
István Bozsó et al.
  • 1Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584 CD, Utrecht, The Netherlands (bozso.istvan@ggki.hu)
  • 2Geodetic and Geophysical Institute, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network (ELKH), Csatkai Endre utca 6.-8., Sopron, Hungary
  • 3Department of Earth Sciences, ETH Zürich, NO H 9.1 Sonneggstrasse 5 8092 Zürich, Switzerland
  • 4Centre for Energy Research, Eötvös Loránd Research Network (ELKH), Konkoly-Thege Miklós út 29-33., Budapest, Hungary

The Carpathians subduction system evolved similarly to many Mediterranean systems where extensional back-arc basins and separate large sag basins develop in the overriding plate. The evolution of such basins can be explained in the context of roll-back of narrow oceanic slabs. Their evolution is linked to extensional and sag back-arc basins, retreating orogenic systems and slab detachment. A recent example of slab detachment can be studied by the Vrancea slab beneath the SE Carpathians.
Significant effort has been dedicated to modelling such Mediterranean-style subduction systems, and in most cases the model was set up with a narrow oceanic domain, which has an increased difficulty to create rollback due to reduced buoyancy of the slab.
Our approach is to use a two-dimensional thermo-mechanical numerical model that introduces an inherited oceanic domain, which adds to the younger, narrow ocean developed in the later stages.
Our model can produce sustained subduction of the oceanic slab associated with roll-back and slab detachment. In most of our models a retro-arc sag basin develops, which can be interpreted as the Transylvanian Basin. This sag basin is one of the most consistent features of our model. At larger distances from the subduction zone, the extensional back-arc of the Pannonian basin can be modelled by introducing an lithospheric weakness zone, which represents a suture zone inherited from a previous orogenic evolution. Such a suture zone is compatible with the overall orogenic evolution of the Alps-Carpathians-Dinarides system. We furthermore discuss the limitations of our 2D modeling in the overall 3D settings of the Carpathians system and possibilities of future integration.

How to cite: Bozsó, I., van Dinther, Y., Matenco, L., Balázs, A., and Kovács, I.: Subduction and roll-back of narrow oceanic slabs: Back-arc basin modelling of the Carpathians subduction zone, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13393, https://doi.org/10.5194/egusphere-egu21-13393, 2021.

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