Published 2006
| Version v1
Journal article
The late extension in the inner western Alps: a synthesis along the south-Pelvoux transect
Contributors
Others:
- Laboratoire de Géodynamique des Chaines Alpines (LGCA) ; Observatoire des Sciences de l'Univers de Grenoble (OSUG) ; Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Géoazur (GEOAZUR 6526) ; Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Laboratoire de Géophysique Interne et Tectonophysique (LGIT) ; Observatoire des Sciences de l'Univers de Grenoble (OSUG) ; Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS)
- Institut de Géologie ; Neuchâtel
Description
During the Oligocene, in the central western Alps, tectonic accretion of the external domain to the internal orogenic wedge along the Briançonnais Frontal Thrust (BFT) was followed by backfolding, resulting in the Alpine fanning structure. The Briançonnais fan axis was rapidly exhumed by erosion. This growing wedge at the scale of the entire Alpine structure was a short-lived situation that ended with the onset of extension in its internal part, before the end Oligocene. To the east, in the Queyras Piedmont Schistes lustrés, extension in ductile then brittle conditions accommodated the tectonic denudation of the Dora-Maira crystalline massif below the Monviso ophiolites, themselves exhumed below the Queyras Schistes lustrés. Consistently, the final cooling of these Schistes lustrés becomes younger eastwards during the Miocene. To the west, inversion of the BFT was directly associated with dense normal faulting in the Briançonnais -Piedmont nappe stack. Local reactivation of thrust surfaces resulted in spectacular trains of tilted blocks oriented parallel and normal to the orogen. When considered at the scale of the entire internal zones, the brittle extension developed during the Neogene globally displays a multitrend character. It is a close to radial spreading that strongly suggests the gravitational collapse of an overthickened crust. Extensional movement along the BFT and multitrend normal faulting in its hangingwall continue at present, resulting in shallow depth seismic activity. From the Neogene onwards, the Alpine structure underwent contrasting tectonic regimes. Extension limited the growth of the internal wedge or accompanied its thinning at least in its upper part. Concurrently the external wedge continued growing through successive folding-thrusting phases.
Abstract
International audienceAdditional details
Identifiers
- URL
- https://hal.science/hal-00130553
- URN
- urn:oai:HAL:hal-00130553v1
Origin repository
- Origin repository
- UNICA