1EDYTEM, Université Savoie Mont Blanc, CNRS 73376 Le Bourget du Lac
2LSCE, Université de Versailles Saint-Quentin CEA-CNRS, Avenue de
la Terrasse, 91198 Gif-sur-Yvette CEDEX, France
3University of Geneva Department of Radiology and Medical Informatics
Genève, Rue Gabrielle-Perret-Gentil 4, C1211, Geneva, Switzerland
Received: 20 Apr 2016 – Discussion started: 13 May 2016
Abstract. Over the past decades, X-ray computed tomography (CT) has been increasingly applied in the geosciences community. CT scanning is a rapid, non-destructive method allowing the assessment of relative density of clasts in natural archives samples. This study focuses on the use of this method to explore instantaneous deposits as major contributors to sedimentation of high-elevation lakes in the Alps, such as the Lake Lauvitel system (western French Alps). This lake is located within a very steep valley prone to episodic flooding and features gullies ending in the lake. This variety of erosion processes leads to deposition of sedimentary layers with distinct clastic properties. We identified 18 turbidites and 15 layers of poorly sorted fine sediment associated with the presence of gravels since AD 1880. These deposits are respectively interpreted as being induced by flood and wet avalanche. This constitutes a valuable record from a region where few historical records exist. This CT scan approach is suitable for instantaneous deposit identification to reconstruct past evolution and may be applicable to a wider variety of sedimentary archives alongside existing approaches.
Revised: 13 Jan 2017 – Accepted: 08 Feb 2017 – Published: 28 Mar 2017
Fouinat, L., Sabatier, P., Poulenard, J., Reyss, J.-L., Montet, X., and Arnaud, F.: A new CT scan methodology to characterize a small aggregation gravel clast contained in a soft sediment matrix, Earth Surf. Dynam., 5, 199-209, doi:10.5194/esurf-5-199-2017, 2017.