Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics
<p>The tectonic evolution of highly oblique continental margins that result from extension above lithospheric subduction–transform edge propagator (STEP) faults is poorly understood. Here, we investigate the case of the Alboran margin in the eastern Betics characterized by crustal thinning of...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-12-01
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| Series: | Solid Earth |
| Online Access: | https://se.copernicus.org/articles/14/1221/2023/se-14-1221-2023.pdf |
| _version_ | 1797401827514253312 |
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| author | M. Larrey M. Larrey F. Mouthereau D. Do Couto E. Masini A. Jourdon S. Calassou V. Miegebielle |
| author_facet | M. Larrey M. Larrey F. Mouthereau D. Do Couto E. Masini A. Jourdon S. Calassou V. Miegebielle |
| author_sort | M. Larrey |
| collection | DOAJ |
| description | <p>The tectonic evolution of highly oblique continental margins that result from extension above lithospheric subduction–transform edge propagator (STEP) faults is poorly understood. Here, we investigate the case of the Alboran margin in the eastern Betics characterized by crustal thinning of 15–10 km, oblique to the direction of slab retreat. The current deformation patterns indicate that oblique rifting is underway. However, it is unclear whether these conditions are those that prevailed during the formation of the metamorphic domes and intramontane basins. We review the temporal and spatial evolution of Neogene sedimentary basins and brittle deformation in the eastern Betics and exploit offshore seismic reflection lines to propose a crustal-scale section across the oblique margin. The history of sediment infill and rates of subsidence combined with the analyses of fault slip data confirm that brittle extension oriented from north 20<span class="inline-formula"><sup>∘</sup></span> E to E–W occurred during an interval spanning from the Serravallian–early Tortonian to the late Tortonian (14–8 Ma). This extension is associated with both normal and strike-slip regimes and the evolution of the strike-slip fault zones flanking the metamorphic domes. The transtensional model forms a coherent scheme linking the ductile deformation associated with metamorphic domes and the formation of E–W- and NW–SE- or NNW–SSE-directed sedimentary basins in the brittle upper crust during the Tortonian. The oblique extension, which is closely associated with STEP faulting, occurred during the regional convergence between Africa and Iberia since the Miocene. Only recently, around 8 Ma, has slab detachment started to migrate westward, leading to tectonic inversion in the eastern Betics. Such a type of narrow oblique-rifted margin associated with transform-like plate boundaries is not unique but is expected to be hardly preserved in the geological record due to the transient nature of retreating subduction systems.</p> |
| first_indexed | 2024-03-09T02:15:57Z |
| format | Article |
| id | doaj.art-88727b4543b44affa4b527d0adcf61ad |
| institution | Directory Open Access Journal |
| issn | 1869-9510 1869-9529 |
| language | English |
| last_indexed | 2024-03-09T02:15:57Z |
| publishDate | 2023-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj.art-88727b4543b44affa4b527d0adcf61ad2023-12-07T05:01:14ZengCopernicus PublicationsSolid Earth1869-95101869-95292023-12-01141221124410.5194/se-14-1221-2023Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern BeticsM. Larrey0M. Larrey1F. Mouthereau2D. Do Couto3E. Masini4A. Jourdon5S. Calassou6V. Miegebielle7Université Paul Sabatier, Géosciences Environnement Toulouse, GET UMR 5563, Toulouse, FranceTOTAL S.A., Centre Scientifique & Technique Jean Féger, 64000 Pau, FranceUniversité Paul Sabatier, Géosciences Environnement Toulouse, GET UMR 5563, Toulouse, FranceSorbonne Université, CNRS-INSU, Institut des Sciences de la Terre Paris, ISTeP UMR 7193, 75005 Paris, FranceM&U sas, 38360 Sassenage, FranceInstitute of Geophysics, Ludwig-Maximilians-Universität München, Munich, GermanyTOTAL S.A., Centre Scientifique & Technique Jean Féger, 64000 Pau, FranceTOTAL S.A., Centre Scientifique & Technique Jean Féger, 64000 Pau, France<p>The tectonic evolution of highly oblique continental margins that result from extension above lithospheric subduction–transform edge propagator (STEP) faults is poorly understood. Here, we investigate the case of the Alboran margin in the eastern Betics characterized by crustal thinning of 15–10 km, oblique to the direction of slab retreat. The current deformation patterns indicate that oblique rifting is underway. However, it is unclear whether these conditions are those that prevailed during the formation of the metamorphic domes and intramontane basins. We review the temporal and spatial evolution of Neogene sedimentary basins and brittle deformation in the eastern Betics and exploit offshore seismic reflection lines to propose a crustal-scale section across the oblique margin. The history of sediment infill and rates of subsidence combined with the analyses of fault slip data confirm that brittle extension oriented from north 20<span class="inline-formula"><sup>∘</sup></span> E to E–W occurred during an interval spanning from the Serravallian–early Tortonian to the late Tortonian (14–8 Ma). This extension is associated with both normal and strike-slip regimes and the evolution of the strike-slip fault zones flanking the metamorphic domes. The transtensional model forms a coherent scheme linking the ductile deformation associated with metamorphic domes and the formation of E–W- and NW–SE- or NNW–SSE-directed sedimentary basins in the brittle upper crust during the Tortonian. The oblique extension, which is closely associated with STEP faulting, occurred during the regional convergence between Africa and Iberia since the Miocene. Only recently, around 8 Ma, has slab detachment started to migrate westward, leading to tectonic inversion in the eastern Betics. Such a type of narrow oblique-rifted margin associated with transform-like plate boundaries is not unique but is expected to be hardly preserved in the geological record due to the transient nature of retreating subduction systems.</p>https://se.copernicus.org/articles/14/1221/2023/se-14-1221-2023.pdf |
| spellingShingle | M. Larrey M. Larrey F. Mouthereau D. Do Couto E. Masini A. Jourdon S. Calassou V. Miegebielle Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics Solid Earth |
| title | Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics |
| title_full | Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics |
| title_fullStr | Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics |
| title_full_unstemmed | Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics |
| title_short | Oblique rifting triggered by slab tearing: the case of the Alboran rifted margin in the eastern Betics |
| title_sort | oblique rifting triggered by slab tearing the case of the alboran rifted margin in the eastern betics |
| url | https://se.copernicus.org/articles/14/1221/2023/se-14-1221-2023.pdf |
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