Gunnell, Y. and Calvet, M. and Meyer, B. and Pinna-Jamme, R. and Bour, I. and Gautheron, C. and Carter, Andrew and Dimitrov, D. (2017) Cenozoic landforms and post-orogenic landscape evolution of the Balkanide orogen: evidence for alternatives to the tectonic denudation narrative in southern Bulgaria. Geomorphology 276 , 203 - 221. ISSN 0169-555X.
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Abstract
Continental denudation is the mass transfer of rock from source areas to sedimentary depocentres, and is typically the result of Earth surface processes. However, a process known as tectonic denudation is also understood to expose deep-seated rocks in short periods of geological time by displacing large masses of continental crust along shallow-angle faults, and without requiring major contributions from surface erosion. Some parts of the world, such as the Basin and Range in the USA or the Aegean province in Europe, have been showcased for their Cenozoic tectonic denudation features, commonly described as metamorphic core-complexes or as supradetachment faults. Based on 22 new apatite fission-track (AFT) and 21 helium (AHe) cooling ages among rock samples collected widely from plateau summits and their adjacent valley floors, and elaborating on inconsistencies between the regional stratigraphic, topographic and denudational records, this study frames a revised perspective on the prevailing tectonic denudation narrative for southern Bulgaria.We conclude that conspicuous landforms in this region, such as erosion surfaces on basement-cored mountain ranges, are not primarily the result of Paleogene to Neogene core-complex formation. They result instead from “ordinary” erosion-driven, subaerial denudation. Rock cooling, each time suggesting at least 2 km of crustal denudation, has exposed shallow Paleogene granitic plutons and documents a 3-stage wave of erosional denudation which progressed from north to south during the Middle Eocene, Oligocene, Early to Middle Miocene, and Late Miocene. Denudation initially prevailed during the Paleogene under a syn-orogenic compressional regime involving piggyback extensional basins (Phase 1), but subsequently migrated southward in response to post-orogenic upper-plate extension driven by trench rollback of the Hellenic subduction slab (Phase 2). Rare insight given by the denudation pattern indicates that trench rollback progressed at a mean velocity of 3 to 4 km/Ma. The Neogene horst-and-graben mosaic that defines the modern landscape (Phase 3) has completely overprinted the earlier fabrics of Phases 1 and 2, and has been the prime focus of tectonic geomorphologists working in the region. The new narrative proposed here for linking the geodynamic evolution of SE Europe with surface landform assemblages raises issues in favour of better documenting the regional sedimentary record of existing Paleogene basins,which constitute a poorly documented missing link to the thermochronological evidence presented here
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | Tectonic geomorphology, Erosion surface, Thermochronology, Denudation rates |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Depositing User: | Andy Carter |
| Date Deposited: | 02 Dec 2016 10:07 |
| Last Modified: | 02 Aug 2023 17:28 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/16779 |
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- Cenozoic landforms and post-orogenic landscape evolution of the Balkanide orogen: evidence for alternatives to the tectonic denudation narrative in southern Bulgaria. (deposited 02 Dec 2016 10:07) [Currently Displayed]
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