Stéphane BONNET

Professeur

Pr Université Paul Sabatier, Toulouse III

Email : stephane.bonnetDear bot, you won't get my mail address@and my domain...get.omp.eu

ER4 - Couplages Lithosphère - Océans - Atmosphère (LOA)

Professor Earth Sciences, Geomorphology, Surface Processes Univ. P Sabatier / Toulouse III ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Recruitment of two PhD students (fully funded, start date september 2022): see "Projects section"----------------------------------------------------------------------------------------------------------------------------------------------------- Please contact me for information

CV / functions

1997 -Thèse de 3ème cycle Univ Rennes 1
1998 – Maitre de Conférences Univ Rennes 1
2005 – HDR Univ Rennes 1
2011 – Professeur Univ. P Sabatier / Toulouse III

Research

Géomorphologie, Erosion continentale, réseaux hydrographiques, modélisation expérimentale, modélisation analogique, luminescence, datations OSL, fleuves, rivières, karsts, terrasses fluviatiles, knickpoints, LIDAR terrestre

Géomorphology, continental erosion, drainage networks, experimental modeling, analog modeling, luminescence, OSL, rivers, karsts, fluvial terraces, knickpoints, terrestrial LIDAR

Responsibilities

Directeur-adjoint Ecole Doctorale SDU2E – « Sciences de l’Univers, de l’Environnement et de l’Espace » : http://sdu2e.obs-mip.fr/

Responsable du Laboratoire de Modélisation de l’Erosion et des Reliefs / GET

Publications

2022

Guyez, A., Bonnet, S., Reimann, T., Carretier, S. and Wallinga, J. Illuminating past river incision, sediment source and pathways using luminescence signals of individual feldspar grains (Rangitikei River, New Zealand). Earth Surf. Process. Landforms, doi:10.1002/esp.5357, 2022.

De Lavaissière, Bonnet, S., Guyez, A. and Davy, P. Autogenic knickpoints in laboratory landscape experiments. Earth Surf. Dyn., 20, 229-246, 2022.

Regard, V., Prémaillon, M., Dewez, T.J.B., Carretier, S., Jeandel, C., Godderis, Y., Bonnet, S ., Schott, J., Pedoja, K., Martinod, J., Viers, J., and Fabre, S. Rock coast erosion: An oberlooked source of sediments to the Ocean. Europe as an example. Earth Planet. Sci. Letters, 579, 2022.

2021

Regard, V., Vacherat, A., Bonnet, S., Mouthereau, F., Nørgaard, J. and Knudsen, M.F. Late Pliocene-Pleistocene incision in the Ebro Basin (North Spain), BSGF-Earth Sciences Bulletin, 192:30, 2021.

Zavala-Ortiz, V., Carretier, S., Regard, V., Bonnet, S., Riquelme, R. and Choy, S. Along-stream variations in valley flank erosion rates measured using 10Be concentrations in colluvial deposits from Atacama canyons: implications for valley widening. Geophysical Research Letters, doi:10.1029/2020GL089961, 2021

2020

Baynes, E., Lague, D., Steer, P., Bonnet, S., and Illien, L. Sediment flux driven channel geometry adjustment of bedrock and mixed gravel-bedrock rivers. Earth Surf. Process. Landforms, doi:10.1002/esp.4996

Carretier, S., Guerit, L., Harries, R., Regard, V., Maffre, P. and Bonnet, S., 2020. The distribution of sediment residence times at the foot of mountains and its implications for proxies recorded in sedimentary basins. Earth Planet. Sci. Lett., 546, doi:10.1016/J.epsl2020.116448

Zavala-Ortiz, V., Carretier, S. and Bonnet S., 2020. Control of orographic precipitation on the topographic and erosional evolution of mountain ranges. Basin Research, doi:10.1111/bre.12443

2019

Bonnet, S., Reimann, T., Wallinga, J., Lague, D., Davy, P., and Lacoste, A., 2019. Landscape dynamics revealed by luminescence signals of feldspars from fluvial terraces Scientific Reports, v. 9, 856, https://doi.org/10.1038/s41598-019-44533-4

Guerit, L., Yuan, X.-P., Carretier, S., Bonnet, S., Rohais, S., Braun, J., and Rouby, D. 2019. Fluvial landscape evolution controlled by the sediment deposition coeffcient : Estimation from experimental and natural landscapes. Geology, https:// doi .org /10 .1130 /G46356.1

Menges, J., Hovius, N., Andermann, C., Dietze, M., Swoboda, C., Cook, K.L., Adhikari, B.R., Vieth‐Hillebrand, A., Bonnet, S., Reimann, T., Koutsodendris, A. and Sachse, D., 2019. Late Holocene landscape collapse of a Trans-Himalayan dryland: Human impact and aridification. Geophysical Research Letters, 46, 13,814-13,824. https:// doi .org /10.1029/2019GL084192.

2018

Moussirou, B. and Bonnet, S., Modulation of the erosion rate of an uplifting landscape by long-term climate change: An experimental investigation. Geomorphology, 303, 456-466, 2018.

Vacherat, A., Bonnet, S., and Mouthereau, F., Drainage reorganization and divide migration induced by the excavation of the Ebro basin (NE Spain). Earth Surf. Dyn., 6, 369-387, 2018.

Liste complète : https://orcid.org/0000-0003-4464-285X

Projects

Co-PI with Pr Tony Reimann (Univ Cologne) of a France-Germany ANR-DFG research project « WEARING_DOWN – The continental weathering-erosion-transport-deposition nexus in a new light » 2022-2025

The main objective of this project is to develop new tools for quantifying sediment production and transfer at the Earth’s surface, from weathering and erosion on hillslopes to transport in fluvial systems, with a particular emphasis on the intermediate time-scale (mesoscale, 10²-10⁴ yrs). This will bridge the gap between event- and geological-scales for which dedicated tools are currently

We will develop new tracing tools of Earth’s surface processes based on natural luminescence of sediments, combined with state-of-the-art quantification of rates of surface processes by in-situ TCN, including the use of in situ cosmogenic ¹⁴C, the recent developments of which allows investigation of surface processes at a shorter time-scale than other TCN-based methods.

The objective of Work Package #1, the “sediment factory”, is to reassess the control of hillslope processes on catchment-wide erosion rates estimated from TCN concentrations measured in fluvial deposits. We will also provide new insights into millennial scale erosion rates. We will determine catchment-wide erosion rates by pairing in situ ¹⁴C and ¹⁰Be measured in fluvial deposits, which will highlight potential changes in erosion rates across time scales. We will jointly develop luminescence-based surface process tracing to better link these rates to surface processes on hillslopes (soil formation and erosion, landsliding).

–> 1 fully funded PhD position available in WP1 (starting date 1 september 2022). Please contact Stéphane Bonnet and Tony Reimann for information and application

The objective of Work Package #2, the “sediment conveyor”, is to develop the use of luminescence-based surface process tracing and in situ TCN for investigating the fate of sediment particles during their source-to-sink transfer in rivers (Allen, 2008). We aim to provide new quantitative estimates of fluvial transport parameters such as the characteristic transport length of the particles and their virtual velocity (velocity averaged over transport and rest times) for different river patterns (braided or not) and their dependency to sediment supply from catchments’ erosion. We also aim to quantify temporal storage of particles in floodplains.

–> 1 fully funded PhD position available in WP2 (starting date 1 september 2022). Please contact Stéphane Bonnet and Tony Reimann for information and application

The objective of Work Package #3 is to develop numerical codes that will help leverage luminescence and TCN data to better understand how sediments are produced on hillslopes, delivered to river networks, transported in fluvial systems and potentially temporarily trapped. The twofold ambition is to understand the acquisition mechanisms of the luminescence and TCN signals and, conversely, to understand the constraints that these signals bring to the river and landscape dynamics. To achieve this, we will develop Landscape Evolution Models (LEMs) capable of transporting a population of grains whose OSL and TCN concentrations vary according to geomorphic conditions.

Teaching

Géologie Générale (L1), Cartographie géologique (L2), Géomorphologie (L3), LIDAR et SIG (M1), Géomorphologie (M2), Communication scientifique (M2), terrain (L3, M1, M2)

Stéphane BONNET

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