Preprints
https://doi.org/10.5194/esurf-2021-49
https://doi.org/10.5194/esurf-2021-49

  15 Jul 2021

15 Jul 2021

Review status: a revised version of this preprint is currently under review for the journal ESurf.

Sediment export in marly badland catchments modulated by frost-cracking intensity, Draix-Bléone Critical Zone Observatory, SE France

Coline Ariagno1, Caroline Le Bouteiller1, Peter van der Beek2, and Sébastien Klotz1 Coline Ariagno et al.
  • 1Univ. Grenoble Alpes, INRAE, UR ETNA, Grenoble, France
  • 2Institut für Geowissenschaften, Universität Potsdam, Germany

Abstract. At the interface between the lithosphere and the atmosphere, the critical zone records the complex interactions between erosion, climate, geologic substrate and life, and can be directly monitored. Long data records collected in the sparsely vegetated, steep marly badland catchments of the Draix-Bléone Critical Zone Observatory (CZO), SE France, allow analysing potential climatic controls on long-term regolith dynamics and sediment export. Although widely accepted as a first-order control, rainfall variability does not fully explain the observed inter-annual variability in sediment export, suggesting that regolith production and its controls may modulate the observed pattern of sediment export. Here, we define sediment-export anomalies as the residuals from a predictive model with annual rainfall intensity above a threshold as the control. We then use continuous soil-temperature data, recorded at different locations over multiple years, to highlight the role of frost weathering in regolith production. Several proxies for different frost-weathering processes have been calculated from these data and compared to the sediment-export anomalies, with careful consideration of field data quality. Our results suggest that frost-cracking intensity (linked to ice segregation) can explain about half (47–64 %) of the sediment-export anomalies. In contrast, the number of freeze-thaw cycles (linked to volumetric expansion) has only a minor impact on catchment sediment response. The time spent below 0 °C also correlates well with the sediment-export anomalies and requires fewer field data to be calculated than the frost-cracking intensity. Thus, frost-weathering processes modulate sediment export by controlling regolith production in these catchments and should be taken into account when building a predictive model of sediment export from these badlands under a changing climate.

Coline Ariagno et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on esurf-2021-49', Anonymous Referee #1, 26 Aug 2021
  • RC2: 'Comment on esurf-2021-49', Anonymous Referee #2, 06 Oct 2021

Coline Ariagno et al.

Coline Ariagno et al.

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Latest update: 02 Dec 2021
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Short summary
The “critical zone” near the surface of the Earth is where geologic substrate, erosion, climate and life meet and interact. This study focuses on mechanisms of physical weathering that produce loose sediment and make it available for transport. We show that the sediment export from a monitored catchment in the French Alps is modulated by frost weathering processes and is therefore sensitive to complex modifications in a warming climate.