| Titre | A GIS-based multi-proxy analysis of the evolution of subglacial dynamics in the Quebec-Labrador ice dome, northeastern Quebec, Canada |
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| Auteur | Rice, J M ; Ross,
M; Paulen, R C; Kelley, S E; Briner, J P |
| Source | Earth Surface Processes and Landforms 2020 p. 1-23, https://doi.org/10.1002/esp.4957  Accès ouvert |
| Image |  |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190357 |
| Éditeur | Wiley |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1002/esp.4957 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Québec |
| SNRC | 23P/13; 23P/14; 23P/15; 23P/16 |
| Lat/Long OENS | -66.0000 -64.0000 56.0000 55.5000 |
| Sujets | antecedents glaciaires; glaciation; écoulement glaciaire; nappes glaciaires; établissement de modèles; topographie glaciaire; dépôts glaciaires; tills; elements glaciaires; affouillements glaciaires;
erosion glaciaire; lacs; paléoenvironnement; altération; géochimie du beryllium; altération; télédétection; imagerie par satellite; interprétations géophysiques; interprétations magnétiques; géologie du substratum rocheux; Calotte glaciaire
Laurentide; tills en couverture continue; directions d'écoulement glaciaire; Système d'information géographique; Données géographiques; Classification; géologie des dépôts meubles/géomorphologie; géochimie; géophysique; Sciences et technologie;
Nature et environnement; Phanérozoïque; Cénozoïque; Quaternaire |
| Illustrations | cartes de localisation; cartes géolscientiques généralisées; modèles altimétriques numériques; images satellitaires; photographies; organigrammes; histogrammes; graphiques; tableaux |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Nord-est du Québec-Labrador, géologie des dépôts meubles de la région
d'Hudson/Ungava |
| Diffusé | 2020 07 17 |
| Résumé | (disponible en anglais seulement)
The glacial records of the inner-core regions of the Laurentide Ice Sheet (LIS) document complex, yet coherent patterns reflecting ice sheet change (e.g.,
ice-divide migration) providing unique insights into past glacial conditions. This study develops a conceptual model of subglacial dynamics evolution within a major ice-dispersal centre of the LIS in northeastern Quebec, Canada using a GIS-based
analysis of the surficial geologic record. Multiple proxies of subglacial conditions (subglacial streamlined landforms, lake density and lake area over thin drift/bedrock), were analyzed through grid-overlay techniques and then classified based on
different proxy variables ranging from highly mobile warm-based to immobile cold-based conditions. An additional proxy (till blanket) was used to identify areas of thick till deposition but with few proxies (few lake or landform metrics). Based on
local ice-flow reconstructions, the most ‘relict’ glacial terrain zone (GTZ1) has warm-based conditions over 66% of its area and is remarkably well-preserved, suggesting laterally extensive warm-based conditions during the oldest identified ice-flow
phase. This relict glacial terrain is partially overprinted by two subsequent ice-flow phases in spatially restricted zones in the northeast (73% warm-based), east-central (41% warm-based), and northwest (33% warm-based) of the study area. A zone of
more sluggish conditions (only 3% warm-based) was identified in the highlands at the centre of the study area, characterized by thin till cover, few landforms, yet with large patches of relatively abundant small lakes, indicative of areal scouring.
No clear evidence of sustained cold-based conditions (i.e., high chemical index of alteration values or high 10Be abundances) were found in the study area. These results suggest warm-based conditions (active erosion and/or deposition) were uniformly
widespread during the earliest ice-flow phase, later becoming more spatially restricted with broader sluggish ice conditions. These spatially restricted regions of warm-based subglacial regimes were likely controlled by surrounding and down-flow ice
streaming. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Une analyse de paysage entreprise dans une ancienne région de fractures de glace pour examiner la vigueur du temps glaciaire, réalisée dans le
cadre d'un projet de recherche de doctorat |
| GEOSCAN ID | 321484 |
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