title: Present-day uplift of the western Alps.
abstract: Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ~2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes.
authors.affiliation: Geoazur, IRD, Université de Nice Sophia-Antipolis, Observatoire de la Côte d'Azur, CNRS, 250, rue A. Einstein, Valbonne, 06560, France.
authors.forename: J-M
authors.initials: JM
authors.lastname: Nocquet
authors.affiliation: Chrono-Environnement, CNRS, Univ. de Bourgogne Franche-Comté, 16, route de Gray, 25030 Besançon, Cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Sue
authors.affiliation: Univ. Grenoble Alpes, ISTerre, F-38000, Grenoble, France.
authors.forename: A
authors.initials: A
authors.lastname: Walpersdorf
authors.affiliation: Geoazur, IRD, Université de Nice Sophia-Antipolis, Observatoire de la Côte d'Azur, CNRS, 250, rue A. Einstein, Valbonne, 06560, France.
authors.forename: T
authors.initials: T
authors.lastname: Tran
authors.affiliation: Aquitaine Agency, Bureau de Recherches Géologiques et Minières, 24 avenue Léonard de Vinci, 33600 Pessac, France.
authors.forename: N
authors.initials: N
authors.lastname: Lenôtre
authors.affiliation: Géosciences Montpellier, CNRS-Université Montpellier 2, Montpellier 34095, France.
authors.forename: P
authors.initials: P
authors.lastname: Vernant
authors.affiliation: IRSN/PRP-DGE/SCAN/BERSSIN, BP 17, 92262 Fontenay-aux-Roses Cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Cushing
authors.affiliation: Université de Savoie Mont Blanc, ISTerre, 73376 Le Bourget-du-Lac, France.
authors.forename: F
authors.initials: F
authors.lastname: Jouanne
authors.affiliation: Institut de Physique du Globe de Strasbourg, Université de Strasbourg/EOST, UMR7516, CNRS, France.
authors.forename: F
authors.initials: F
authors.lastname: Masson
authors.affiliation: IRSN/PRP-DGE/SCAN/BERSSIN, BP 17, 92262 Fontenay-aux-Roses Cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Baize
authors.affiliation: Géosciences Montpellier, CNRS-Université Montpellier 2, Montpellier 34095, France.
authors.forename: J
authors.initials: J
authors.lastname: Chéry
authors.affiliation: Univ. Grenoble Alpes, ISTerre, F-38000, Grenoble, France.
authors.forename: P A
authors.initials: PA
authors.lastname: van der Beek