| Titre | Geomorphology of a late Wisconsin hard-bedded ice stream landsystem, Ontario, Canada revealed by high resolution LiDAR mapping |
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| Auteur | Bukhari, S S A; Sookhan, S; Eyles, N; Shi, Y; Mulligan, R P M; Paulen, R C |
| Source | GSA 2020 Connects Online - Geological Society of America Annual Meeting; Geological Society of America, Abstracts With Programs vol. 52, no. 6, 2020 p. 1, https://doi.org/10.1130/abs/2020AM-357973  Accès
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| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200503 |
| Éditeur | Geological Society of America |
| Réunion | GSA 2020: Geological Society of America Annual Meeting 2020; Octobre 26-30, 2020 |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1130/abs/2020AM-357973 |
| Media | en ligne; numérique |
| Formats | html; pdf |
| Province | Ontario |
| SNRC | 31B; 31C; 31D; 31E; 31F; 31G |
| Région | Fleuve Saint-Laurent |
| Lat/Long OENS | -79.5000 -74.2500 45.6333 43.7500 |
| Sujets | antecedents glaciaires; glaciation; Wisconsinien; écoulement glaciaire; déglaciation; retrait de la glace; marges glaciaires; levés géophysiques; modèles; topographie glaciaire; dépôts glaciaires;
elements glaciaires; moraines; buttes; moraine, de geer; argiles; formation de fissures; congélation du sol; cannelures glaciaires; lacs glaciaires; icebergs; érosions par la glace; Calotte glaciaire Laurentide; Moraine de Dummer ; Lac glaciaire
d'Iroquois; courants glaciaires; crêtes morainiques; sédiments glaciolacustres; géologie des dépôts meubles/géomorphologie; géophysique; Nature et environnement; Sciences et technologie; Phanérozoïque; Cénozoïque; Quaternaire |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Cartographie des dépôts meubles du sud du Mackenzie du corridor de Mackenzie |
| Diffusé | 2020 10 01 |
| Résumé | (disponible en anglais seulement)
The 'age of LiDAR' is revolutionizing the study of the Earth's surface. This paper showcases the enhanced utility of 3-D surface visualization models derived
from high-resolution LiDAR data sets over traditionally used 2-D models for the purpose of qualitatively discriminating, classifying and mapping subtle hitherto unmapped glacial landforms left behind by the retreat of a hard-bedded paleo-ice stream
(Ontario Ice Stream: OIS) within the Laurentide Ice Sheet in Eastern Ontario, Canada. The hard bed consists of flat-lying Paleozoic limestone plains extending as a broad west-east belt immediately south of the Canadian Shield from Lake Huron to the
St. Lawrence River Valley. The largest landform is the Dummer Moraine along the Shield-Paleozoic boundary consisting of undulating hummocky topography composed entirely of clast-supported limestone rubble with large detached bedding plane slabs the
result of subglacial hydrofracturing and bed-freezing below a thin retreating ice margin along the northern limit of Paleozoic carbonates. Southward dipping limestone bedding plane surfaces, expressed as extensive bare plains, show swaths of parallel
linear grooves cut by fast flowing ice entraining subglacial debris dominated by hard Shield lithologies. The southern and lowest part of the hard bed near Lake Ontario was covered by waters of glacial Lake Iroquois a much larger late glacial
precursor to Lake Ontario that drained abruptly at about ~13 cal kyr BP though the Hudson River Valley. Seasonal calving of ice bergs from the retreating ice stream margin standing in glacial Lake Iroquois is recorded by swaths of De Geer moraine
ridges composed of bulldozed glaciolacustrine clay and identify an annual ice margin retreat rate between 30 and 100 m. A related but subtle landscape element comprises hundreds of linear to curvilinear ice scours up to 3 km long. This paper
highlights the growing importance of geoinformatics techniques in the field of glaciology and the understanding of ice sheet beds and reiterates the need for further research into the application of more advanced computer vision techniques. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Une présentation lors d'une conférence internationale mettant en évidence le potentiel et l'utilité des données LiDAR haute résolution en tant
qu'outil puissant de cartographie de surface, démontré dans une région au nord de Toronto, dans le sud de l'Ontario. |
| GEOSCAN ID | 327414 |
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