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The periglacial engine of mountain erosion

  • There is growing recognition of strong periglacial control on bedrock erosion in mountain landscapes, including the shaping of low-relief surfaces at high elevations (summit flats). But, as yet, the hypothesis that frost action was crucial to the assumed Late Cenozoic rise in erosion rates remains compelling and untested. Here we present a landscape evolution model incorporating two key periglacial processes - regolith production via frost cracking and sediment transport via frost creep - which together are harnessed to variations in temperature and the evolving thickness of sediment cover. Our computational experiments time-integrate the contribution of frost action to shaping mountain topography over million-year timescales, with the primary and highly reproducible outcome being the development of flattish or gently convex summit flats. A simple scaling of temperature to marine delta O-18 records spanning the past 14 Myr indicates that the highest summit flats in mid-to high-latitude mountains may have formed via frost action priorThere is growing recognition of strong periglacial control on bedrock erosion in mountain landscapes, including the shaping of low-relief surfaces at high elevations (summit flats). But, as yet, the hypothesis that frost action was crucial to the assumed Late Cenozoic rise in erosion rates remains compelling and untested. Here we present a landscape evolution model incorporating two key periglacial processes - regolith production via frost cracking and sediment transport via frost creep - which together are harnessed to variations in temperature and the evolving thickness of sediment cover. Our computational experiments time-integrate the contribution of frost action to shaping mountain topography over million-year timescales, with the primary and highly reproducible outcome being the development of flattish or gently convex summit flats. A simple scaling of temperature to marine delta O-18 records spanning the past 14 Myr indicates that the highest summit flats in mid-to high-latitude mountains may have formed via frost action prior to the Quaternary. We suggest that deep cooling in the Quaternary accelerated mechanical weathering globally by significantly expanding the area subject to frost. Further, the inclusion of subglacial erosion alongside periglacial processes in our computational experiments points to alpine glaciers increasing the long-term efficiency of frost-driven erosion by steepening hillslopes.show moreshow less

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Metadaten
Author:David L. Egholm, Jane Lund Andersen, Mads Faurschou Knudsen, John D. JansenORCiD, S. B. Nielsen
URN:urn:nbn:de:kobv:517-opus4-409718
DOI:https://doi.org/10.25932/publishup-40971
ISSN:1866-8372
Parent Title (English):Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
Subtitle (English):Part 2: Modelling large-scale landscape evolution
Series (Serial Number):Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (552)
Document Type:Postprint
Language:English
Date of first Publication:2019/01/28
Year of Completion:2015
Publishing Institution:Universität Potsdam
Release Date:2019/01/28
Tag:AL-26; New-Zealand; climate; glacial erosion; rates; sediment; situ produced BE-10; southern Alps; surfaces; uplift
Issue:552
Pagenumber:20
Source:Earth Surface Dynamics 3 (2015), pp. 463–482 DOI 10.5194/esurf-3-463-2015
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Peer Review:Referiert
Publication Way:Open Access
Grantor:Copernicus
Licence (German):License LogoCreative Commons - Namensnennung, 4.0 International
Notes extern:Bibliographieeintrag der Originalveröffentlichung/Quelle