Preprints
https://doi.org/10.5194/esurf-2021-12
https://doi.org/10.5194/esurf-2021-12

  25 Feb 2021

25 Feb 2021

Review status: a revised version of this preprint was accepted for the journal ESurf and is expected to appear here in due course.

Last glacial cycle glacier erosion potential in the Alps

Julien Seguinot1 and Ian Delaney2 Julien Seguinot and Ian Delaney
  • 1Independent scholar, Anafi, Greece
  • 2Institute of Earth Surface Dynamics, University of Lausanne, Switzerland

Abstract. The glacial landscape of the Alps has fascinated generations of explorers, artists, mountaineers and scientists with its diversity, including erosional features of all scales from high-mountain cirques, to steep glacial valleys and large over-deepened basins. Using previous glacier modelling results, and empirical inferences of bedrock erosion under modern glaciers, we compute a distribution of potential glacier erosion in the Alps over the last glacial cycle from 120 000 years ago to the present. Despite large uncertainties pertaining to the climate history of the Alps and unconstrained glacier erosion processes, the resulting modelled patterns of glacier erosion include persistent features. The cumulative imprint of the last glacial cycle shows a very strong localization of glacier erosion with local maxima at the mouths of major Alpine valleys and some other upstream sections where glaciers are modelled to have flown with the highest velocity. The modelled erosion rates vary significantly through the glacial cycle, but show paradoxically little relation to the total glacier volume. Phases of glacier advance and maximum extension see a localization of rapid erosion rates at low elevation, while glacier erosion at higher elevation is modelled date from phases of less extensive glaciation. The modelled erosion rates peak during deglaciation phases, when frontal retreat results in steeper glacier surface slopes, implying that climatic conditions that result in rapid glacier erosion might be quite transient and specific. Our results depict the Alpine glacier erosion landscape as a time-transgressive patchwork, with different parts of the range corresponding to different glaciation stages and time periods.

Julien Seguinot and Ian Delaney

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on esurf-2021-12', Anonymous Referee #1, 24 Mar 2021
    • AC1: 'Authors' response on RC1', Julien Seguinot, 01 Jun 2021
  • RC2: 'Comment on esurf-2021-12', Ian Evans, 04 Apr 2021
    • AC2: 'Authors' response on RC2', Julien Seguinot, 01 Jun 2021

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on esurf-2021-12', Anonymous Referee #1, 24 Mar 2021
    • AC1: 'Authors' response on RC1', Julien Seguinot, 01 Jun 2021
  • RC2: 'Comment on esurf-2021-12', Ian Evans, 04 Apr 2021
    • AC2: 'Authors' response on RC2', Julien Seguinot, 01 Jun 2021

Julien Seguinot and Ian Delaney

Data sets

Alpine ice sheet erosion potential aggregated variables Julien Seguinot https://doi.org/10.5281/zenodo.4495419

Video supplement

Alpine glaciers erosion potential over the last 120000 years Julien Seguinot https://vimeo.com/503162771

Alpine glacial cycle erosion vs ice volume Julien Seguinot https://vimeo.com/512478926

Alpine glacial cycle erosion vs bedrock altitude Julien Seguinot https://vimeo.com/512479008

Julien Seguinot and Ian Delaney

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Short summary
Ancient Alpine glaciers have carved a fascinating landscape of piedmont lakes, glacial valleys and mountain cirques. Using a previous supercomputer simulation of glacier flow, we show that glacier erosion has constantly evolved and moved to different parts of the Alps. Interestingly, larger glaciers do not always cause more rapid erosion. Instead, glacier erosion is modelled to slow down during glacier advance and to peak during phases of retreat, such as Earth currently undergoes.