Fulltext

The Chironico landslide (Valle Leventina, southern Swiss Alps): age and evolution

Claude, Anne ; Ivy-Ochs, Susan ; Kober, Florian ; Antognini, Marco ; Salcher, Bernhard ; Kubik, Peter

In: Swiss Journal of Geosciences, 2014, vol. 107, no. 2-3, p. 273-291

Ajouter à la liste personnelle
    Titre
    • The Chironico landslide (Valle Leventina, southern Swiss Alps): age and evolution
    Auteur
    • Claude, Anne. Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092, Zurich, Switzerland
    • Ivy-Ochs, Susan. Laboratory of Ion Beam Physics (LIP), ETH Zurich, Otto-Stern-Weg 5, 8093, Zurich, Switzerland
    • Kober, Florian. Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092, Zurich, Switzerland
    • Antognini, Marco. Museo Cantonale di storia naturale, Viale Cattaneo 4, 6900, Lugano, Switzerland
    • Salcher, Bernhard. Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092, Zurich, Switzerland
    • Kubik, Peter. Laboratory of Ion Beam Physics (LIP), ETH Zurich, Otto-Stern-Weg 5, 8093, Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Swiss Journal of Geosciences, 2014, vol. 107, no. 2-3, p. 273-291. Springer Basel
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:324937
    Summary
    In this study, we focus on the postglacial Chironico landslide in Valle Leventina, the valley of the Ticino river immediately south of the Gotthard pass (southern Swiss Alps). At Chironico, 530 millionm3 of granite gneiss detached from the eastern wall of Valle Leventina and slid along valley-ward dipping foliation joints and fractures. The slide mass was deposited into the valley bottom and blocked the Ticino river, as well as a tributary, the Ticinetto stream, on the opposite side of the valley. Wood fragments found in lacustrine sediments in the slide-dammed upstream lake were previously dated, yielding a minimum age for the landslide of approximately 13,500calyears BP. Based on the deposit morphology, the landslide was in the past interpreted as being composed of two events. In order to directly date the landslide, ten boulders were dated using the cosmogenic nuclides 10Be and 36Cl. Mean exposure ages indicate that the landslide occurred at 13.38±1.03ka BP, during the Bølling-Allerød interstadial. This implies that the Chironico landslide, one of the few pre-Holocene slides known in Alps, is also the oldest in crystalline rock. With runout modelling using DAN3D we could reproduce the hypothesized single-event failure scenario, as well as the character and extent of motion of the landslide mass. Both the ages and the modelling suggest that the landslide was released in one event around 3,000years following deglaciation.