The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution
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 assum...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-10-01
|
| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/3/463/2015/esurf-3-463-2015.pdf |
| _version_ | 1818537168580116480 |
|---|---|
| author | D. L. Egholm J. L. Andersen M. F. Knudsen J. D. Jansen S. B. Nielsen |
| author_facet | D. L. Egholm J. L. Andersen M. F. Knudsen J. D. Jansen S. B. Nielsen |
| author_sort | D. L. Egholm |
| collection | DOAJ |
| description | 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 δ<sup>18</sup>O 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. |
| first_indexed | 2024-12-11T18:47:18Z |
| format | Article |
| id | doaj.art-ed446b6644c24e5d9eb622108f157650 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-12-11T18:47:18Z |
| publishDate | 2015-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-ed446b6644c24e5d9eb622108f1576502022-12-22T00:54:25ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2015-10-013446348210.5194/esurf-3-463-2015The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolutionD. L. Egholm0J. L. Andersen1M. F. Knudsen2J. D. Jansen3S. B. Nielsen4Department of Geoscience, Aarhus University. Høegh-Guldbergs Gade 2, 8000 Aarhus C, DenmarkDepartment of Geoscience, Aarhus University. Høegh-Guldbergs Gade 2, 8000 Aarhus C, DenmarkDepartment of Geoscience, Aarhus University. Høegh-Guldbergs Gade 2, 8000 Aarhus C, DenmarkInstitute of Earth and Environmental Science, University of Potsdam, Potsdam, GermanyDepartment of Geoscience, Aarhus University. Høegh-Guldbergs Gade 2, 8000 Aarhus C, DenmarkThere 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 δ<sup>18</sup>O 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.http://www.earth-surf-dynam.net/3/463/2015/esurf-3-463-2015.pdf |
| spellingShingle | D. L. Egholm J. L. Andersen M. F. Knudsen J. D. Jansen S. B. Nielsen The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution Earth Surface Dynamics |
| title | The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution |
| title_full | The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution |
| title_fullStr | The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution |
| title_full_unstemmed | The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution |
| title_short | The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution |
| title_sort | periglacial engine of mountain erosion ndash part 2 modelling large scale landscape evolution |
| url | http://www.earth-surf-dynam.net/3/463/2015/esurf-3-463-2015.pdf |
| work_keys_str_mv | AT dlegholm theperiglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT jlandersen theperiglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT mfknudsen theperiglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT jdjansen theperiglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT sbnielsen theperiglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT dlegholm periglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT jlandersen periglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT mfknudsen periglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT jdjansen periglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution AT sbnielsen periglacialengineofmountainerosionndashpart2modellinglargescalelandscapeevolution |