Afar triple junction triggered by plume-assisted bi-directional continental break-up.
- Koptev A Sorbonne Université, CNRS, Institut des Sciences de la Terre de Paris (ISTeP), Paris, France. alexander.koptev@ifg.uni-tuebingen.de.
- Gerya T ETH-Zurich, Institute of Geophysics, Sonnegstrasse 5, 8092, Zurich, Switzerland.
- Calais E Ecole Normale Supérieure, Department of Geosciences, PSL Research University, CNRS UMR 8538, Paris, France.
- Leroy S Sorbonne Université, CNRS, Institut des Sciences de la Terre de Paris (ISTeP), Paris, France.
- Burov E Sorbonne Université, CNRS, Institut des Sciences de la Terre de Paris (ISTeP), Paris, France.
- 2018-10-05
Published in:
- Scientific reports. - 2018
English
Divergent ridge-ridge-ridge (R-R-R) triple junctions are one of the most remarkable, yet largely enigmatic, features of plate tectonics. The juncture of the Arabian, Nubian, and Somalian plates is a type-example of the early development stage of a triple junction where three active rifts meet at a 'triple point' in Central Afar. This structure may result from the impingement of the Afar plume into a non-uniformly stressed continental lithosphere, but this process has never been reproduced by self-consistent plume-lithosphere interaction experiments. Here we use 3D thermo-mechanical numerical models to examine the initiation of plume-induced rift systems under variable far-field stress conditions. Whereas simple linear rift structures are preferred under uni-directional extension, we find that more complex patterns form in response to bi-directional extension, combining one or several R-R-R triple junctions. These triple junctions optimize the geometry of continental break-up by minimizing the amount of dissipative mechanical work required to accommodate multi-directional extension. Our models suggest that Afar-like triple junctions are an end-member mode of plume-induced bi-directional rifting that combines asymmetrical northward pull and symmetrical EW extension at similar rates.
- Language
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- English
- Open access status
- gold
- Identifiers
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- DOI 10.1038/s41598-018-33117-3
- PMID 30283091
- Persistent URL
- https://sonar.ch/global/documents/181654
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