| Titre | Timing, rates and geomorphic controls on Holocene loess and aeolian sand deposition using multiple chronometric methods, southeastern Cordillera, Alberta, Canada |
| |
| Auteur | Wolfe, S A ; Lian,
O B |
| Source | Aeolian Research vol. 50, 100687, 2021 p. 1-16, https://doi.org/10.1016/j.aeolia.2021.100687 |
| Image |  |
| Année | 2021 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200054 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.aeolia.2021.100687 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Alberta |
| SNRC | 82O; 82N/09; 82N/15; 82N/16; 83B/03; 83B/04; 83B/05; 83B/06; 83B/11; 83B/12; 83B/13; 83B/14; 83C; 83D; 83E; 83F; 83G/04; 83G/05 |
| Lat/Long OENS | -120.0000 -114.0000 54.0000 51.0000 |
| Sujets | Holocène; loess; dépôts éoliens; téphrochronologie; datation au radiocarbone; Cordillère canadienne; Changement climatique; géologie des dépôts meubles/géomorphologie; géochronologie; Sciences et
technologie; Nature et environnement; Phanérozoïque; Cénozoïque; Quaternaire |
| Illustrations | cartes de localisation; tableaux; diagrammes ternaires; graphiques; photographies; échelles stratigraphiques; coupes schématiques |
| Programme | Géosciences de changements climatiques Pergélisols |
| Diffusé | 2021 03 06 |
| Résumé | (disponible en anglais seulement)
Glacier-fed river systems represent potentially significant sediment sources for aeolian processes owing to sediment production, flow seasonality, and winds
within mountain settings. We investigate the timing and rates of Holocene loess and aeolian sand deposition in three major river valleys (Bow, North Saskatchewan and Athabasca) of the southeastern Canadian Cordillera through aeolian stratigraphy and
dating of sedimentary materials. Source sediments are glacially-derived, seasonally-exposed alluvial deposits. Variation in river morphology promotes source-sediment deposition influenced by bedrock configuration, tributary stream deposition and
alluvial fans. Two main settings for aeolian deposition are source-proximal valley-bottom sites and more distal lower-valley sites in sub-alpine and montane forest ecozones. Dating is well-constrained by radiocarbon ages and tephrochronology. Quartz
optical dating is complicated, likely owing to minimal recycling of grains and quartz provenance. Mass accumulation rates (MARs) indicate that aeolian deposition was initiated soon after deglaciation and has occurred nearly continuously for at least
10000 years. Loess MARs ranged between 100 and 2500 g?m?? 2?a?? 1 during the Holocene. Rates in the last 3000 years are generally two to three times higher than those observed for earlier periods, and are highest in most recent times. We attribute
Holocene accumulation at these sites in general to fluvial source sediment availability and the efficacy of forested valleys as sediment traps. The late Holocene increase in MARs is primarily attributed to increased glacial silt and alluvial sediment
supply during neoglacial fluctuations including the Little Ice Age. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette étude documente les dépôts éoliens le long des rivières de la Cordillère méridionale canadienne. Les taux de dépôt sont généralement plus
élevés que précédemment envisagés. Les systèmes fluviaux avec des bassins de dépôt peu profonds sont des sources de sédiments. Des dépôts éoliens se sont produits en raison de sources de sédiments localisées cohérentes. L'augmentation récente des
taux de dépôt peut être attribuée à l'augmentation du limon des glaciers. |
| GEOSCAN ID | 328172 |
|
|