| Titre | Quaternary stratigraphy and glacial history at Peace River, Alberta: implications for mapping and modeling of older continental ice sheet limits in western Canada |
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| Auteur | Paulen, R C ;
Beaudoin, A B; Ross, M |
| Source | XXI INQUA Congress - Program with Abstracts; par INQUA; 2023 p. 1 |
| Liens | Online - En ligne
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| Image |  |
| Année | 2023 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20220377 |
| Éditeur | INQUA |
| Réunion | XXI INQUA Congress; Rome; IT; juillet 14-20, 2023 |
| Document | livre |
| Lang. | anglais |
| Media | papier; numérique; en ligne |
| Formats | pdf |
| Province | Alberta |
| Région | Rivière de la Paix |
| Sujets | glaciologie; Stratigraphie; Sciences et technologie; géologie générale; Quaternaire |
| Programme | GEM-GéoNord : La géocartographie de l'énergie et des minéraux Coordination du programme GEM |
| Diffusé | 2023 07 14 |
| Résumé | (disponible en anglais seulement)
The number and style of the continental Laurentide Ice Sheet (LIS) glacial advances in the western prairies of North America has been the subject of debate,
especially in the Peace River district of western Alberta and eastern British Columbia. Given its northern Alberta location, resolving the glacial record of this area has important implications for understanding the evolution of the LIS, especially
during its earlier (pre-Late Wisconsin) phases. The Quaternary stratigraphy documented in Alberta’s Peace River lowlands has been subject to conflicting interpretations. This is probably due to the absence of a single complete stratigraphic sequence
preserved at any one section (reflecting extensive landsliding along the Peace River valley), and a lack of chronologic control for lower parts of the sequence.
The valley-fill sediments located at the confluence of the Heart and Peace rivers,
within the town of Peace River, Alberta, provide perhaps the best record in the Interior Plains of western Canada of an almost continuous sequence of Quaternary sedimentation extending from the bedrock surface to present. Here, a 187 m thick
composite stratigraphy records the transition from preglacial fluvial sedimentation (Unit 1), to a penultimate proglacial sedimentary sequence (Units 2 and 3) that is conformably overlain by interstadial fluvial sediments (Unit 4) of possible MIS-3
age, or older (based on limiting radiocarbon dates). In turn, these sediments are overlain by a Late Wisconsin ice advance/retreat cycle of sedimentation from the LIS (Units 5-8). The sequence is capped with Holocene loess with paleosols, containing
mollusc and plant macrofossils. The only till unit in the stratigraphy (Unit 7) is from the Late Wisconsin glacial advance. Clasts of Canadian Shield lithologies in the lower fluvial sediments (Unit 2) are derived from southwestward draining southern
Buffalo Head Hills catchments, where multiple, older glacial sediments have been documented. Consequently, we argue that there is evidence for only a single continental (Laurentide) glaciation in the eastern Peace River district, similar to what is
defined to the southwest in Quaternary exposures along the Smoky River. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Résumé de la stratigraphie des événements glaciaires pour le secteur nord-ouest de l'inlandsis laurentidien, dans l'une des plus grandes vallées
préglaciaires du nord-ouest du Canada. Les unités sédimentaires qui y sont exposées ont rarement été documentées dans leur intégralité. Ceci est important pour contraindre les anciens modèles de calotte glaciaire, qui sont souvent construits pour
l'ensemble de l'hémisphère nord. |
| GEOSCAN ID | 330951 |
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