The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers
<p>In steep landscapes, river incision sets the pace of landscape evolution. Transport of coarse sediment controls incision by evacuating material delivered to river channels by landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-07-01
|
| Series: | Earth Surface Dynamics |
| Online Access: | https://esurf.copernicus.org/articles/10/705/2022/esurf-10-705-2022.pdf |
| _version_ | 1811296759233642496 |
|---|---|
| author | M. P. Dahlquist A. J. West |
| author_facet | M. P. Dahlquist A. J. West |
| author_sort | M. P. Dahlquist |
| collection | DOAJ |
| description | <p>In steep landscapes, river incision sets the pace of landscape evolution. Transport of coarse sediment controls incision by evacuating material delivered to river channels by landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-driven floods. Glacial lake outburst floods (GLOFs) mobilize these boulders and drive incision, yet their role in regional-scale erosion is poorly understood, largely because of their rarity. Here, we find a topographic signature consistent with widespread GLOF erosion in the Nepal Himalaya. Our interpretations emerge from the analysis of normalized channel steepness patterns, knickpoint distributions, and valley wideness. In rivers with glaciated headwaters that generate GLOFs, valleys stay narrow and relatively free of sediment, with bedrock often exposed to erosion. In turn, tributaries to these valleys are steep, allowing less efficient erosional regimes to keep pace with GLOF-driven incision. Where GLOFs are less frequent, valleys are more alluviated and incision stalls. Our results suggest that the extent of headwater glaciation may play an important role in the erosion of Himalayan river valleys and deserves more attention in future work.</p> |
| first_indexed | 2024-04-13T05:54:12Z |
| format | Article |
| id | doaj.art-84e970d1c9c2495bae4b9cfaa5fad853 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-04-13T05:54:12Z |
| publishDate | 2022-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-84e970d1c9c2495bae4b9cfaa5fad8532022-12-22T02:59:41ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2022-07-011070572210.5194/esurf-10-705-2022The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan riversM. P. Dahlquist0A. J. West1Department of Earth and Environmental Systems, Sewanee, The University of the South, Sewanee, TN 37383, USADepartment of Earth Sciences, University of Southern California, Los Angeles, CA 90089, USA<p>In steep landscapes, river incision sets the pace of landscape evolution. Transport of coarse sediment controls incision by evacuating material delivered to river channels by landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-driven floods. Glacial lake outburst floods (GLOFs) mobilize these boulders and drive incision, yet their role in regional-scale erosion is poorly understood, largely because of their rarity. Here, we find a topographic signature consistent with widespread GLOF erosion in the Nepal Himalaya. Our interpretations emerge from the analysis of normalized channel steepness patterns, knickpoint distributions, and valley wideness. In rivers with glaciated headwaters that generate GLOFs, valleys stay narrow and relatively free of sediment, with bedrock often exposed to erosion. In turn, tributaries to these valleys are steep, allowing less efficient erosional regimes to keep pace with GLOF-driven incision. Where GLOFs are less frequent, valleys are more alluviated and incision stalls. Our results suggest that the extent of headwater glaciation may play an important role in the erosion of Himalayan river valleys and deserves more attention in future work.</p>https://esurf.copernicus.org/articles/10/705/2022/esurf-10-705-2022.pdf |
| spellingShingle | M. P. Dahlquist A. J. West The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers Earth Surface Dynamics |
| title | The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers |
| title_full | The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers |
| title_fullStr | The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers |
| title_full_unstemmed | The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers |
| title_short | The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers |
| title_sort | imprint of erosion by glacial lake outburst floods in the topography of central himalayan rivers |
| url | https://esurf.copernicus.org/articles/10/705/2022/esurf-10-705-2022.pdf |
| work_keys_str_mv | AT mpdahlquist theimprintoferosionbyglaciallakeoutburstfloodsinthetopographyofcentralhimalayanrivers AT ajwest theimprintoferosionbyglaciallakeoutburstfloodsinthetopographyofcentralhimalayanrivers AT mpdahlquist imprintoferosionbyglaciallakeoutburstfloodsinthetopographyofcentralhimalayanrivers AT ajwest imprintoferosionbyglaciallakeoutburstfloodsinthetopographyofcentralhimalayanrivers |