| Titre | LiDAR mapping of drumlinoids formed by erosion below a deforming subglacial erodent layer at Saskatchewan Glacier, Canadian Rocky Mountains |
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| Auteur | Bukhari, S ;
Eyles, N; Putkinen, N; Paulen, R C; Akçar, N; Meulendyk, T |
| Source | XXI INQUA Congress 2023, abstracts; 2023 p. 1 |
| Liens | Online - En ligne
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| Image |  |
| Année | 2023 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20220372 |
| Éditeur | INQUA |
| Réunion | XXI INQUA Congress 2023; Rome; IT; juillet 13-20, 2023 |
| Document | livre |
| Lang. | anglais |
| Media | numérique; en ligne |
| Formats | pdf |
| Province | Alberta |
| SNRC | 82O |
| Lat/Long OENS | -116.0000 -114.0000 52.0000 51.0000 |
| Sujets | erosion glaciaire; glaciers; transport des sediments; dépôts glaciaires; établissement de modèles; géologie des dépôts meubles/géomorphologie |
| Programme | Division de la CGC du Centre du Canada |
| Diffusé | 2023 07 19 |
| Résumé | (disponible en anglais seulement)
Saskatchewan Glacier is the longest (12 km) outlet glacier of the Columbia Icefields in the Canadian Rocky Mountains of Alberta, Canada and attained its maximum
Little Ice Age (LIA) extent in 1853. Unusually, for valley glaciers in the region which flow for the most part over hard rock beds, the retreat of Saskatchewan Glacier is exposing an extensive (10 km2) till bed with numerous low relief drumlinoids
revealed by high resolution (+10, 000 pts/m2) LiDAR mapping. These are cored by antecedent sediment (glaciofluvial outwash, glaciolacustrine silt, and valley side alluvial fan debris) draped erosively by a thin (< 1 m) clast-rich LIA till. Drumlinoid
surfaces have been extensively striated by individual clasts and clast clusters being swept across underlying sediments within a clast-rich subglacial traction carpet (erodent layer) now preserved as a thin (< 1 m) 'traction till.' Drumlinoid
surfaces closely resemble slickensided fault planes. Larger boulders being driven across drumlinoids d left plough marks in their wakes and crescentic ramps of thickened till wrapped around their leading edges. Subglacial debris was driven to the ice
margin and swept forward during winter and episodic multi-year still stands, into hummocky push moraines. Soft till was also squeezed into irregular ridges at the base of crevasses, and molded in the lee of large, lodged boulders into longer flutes
that propagated in length downglacier. LiDAR and outcrop data confirm that drumlinoids are the product of erosional streamlining of overridden sediment by a deforming subglacial clast-rich 'erodent layer' between ice and its bed. The same fundamental
erosional stratigraphy, where a thin till cap truncates older streamlined sediments occurs widely below the beds of other retreating LIA glaciers indicating the global relevance of the erodent layer model. The work reported here underscores the need
to expand high resolution LIDAR mapping of Little Ice Age and Pleistocene glacier beds. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Il s'agit d'une présentation basée sur un relevé LiDAR à haute résolution très récent des avant-pays du glacier Saskatchewan, des champs de
glace Columbia dans les montagnes Rocheuses de l'Alberta. Ce type de relevé n'a jamais été effectué à cet endroit, ni à aucun endroit glaciaire terrestre moderne (à cette résolution). Les données à haute résolution nous permettront d'examiner comment
le lit de glace glaciaire a interagi et érodé les sédiments sous-jacents, ce qui révèle à son tour les processus qui forment le till et créent des formes de lit glaciaires simplifiées. |
| GEOSCAN ID | 330937 |
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