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Laurentide Ice-Flow Patterns Document generated on 09/25/2021 3:50 p.m. Géographie physique et Quaternaire Laurentide Ice-Flow Patterns: A Historical Review, and Implications of the Dispersal of Belcher Islands Erratics Historique des modes d’écoulement de l’Inlandsis laurentidien et incidences de la dispersion des blocs erratiques de l’archipel de Belcher Victor K. Prest Volume 44, Number 2, 1990 Article abstract This paper deals with the evolution of ideas concerning the configuration of URI: https://id.erudit.org/iderudit/032812ar flow patterns of the great inland ice sheets east of the Cordillera. The DOI: https://doi.org/10.7202/032812ar interpretations of overall extent of Laurentide ice have changed little in a century (except in the Arctic) but the manner of growth, centres of outflow, See table of contents and ice-flow patterns, remain somewhat controversial. Present geological data however, clearly favour the notion of multiple centres of ice flow. The first map of the extent of the North American ice cover was published in 1881. A Publisher(s) multi-domed concept of the ice sheet was illustrated in an 1894 sketch-map of radial flow from dispersal areas east and west of Hudson Bay. The first large Les Presses de l'Université de Montréal format glacial map of North America was published in 1913. The binary concept of the ice sheet was in vogue until 1943 when a single centre in Hudson ISSN Bay was proposed, based on the westward growth of ice from Labrador/Québec. This Hudson dome concept persisted but was not illustrated 0705-7199 (print) until 1977. By this time it was evident from dispersal studies that the single 1492-143X (digital) dome concept was not viable. Dispersal studies clearly indicate long-continued westward ice flow from Québec into and across southern Hudson Bay, as well Explore this journal as eastward flow from Keewatin into the northern part of the bay. Computer-type modelling of the Laurentide ice sheet(s) further indicates their complex nature. The distribution of two indicator erratics from the Cite this article Proterozoicage Belcher Island Fold Belt Group help constrain ice flow models. These erratics have been dispersed widely to the west, southwest and south by Prest, V. K. (1990). Laurentide Ice-Flow Patterns: A Historical Review, and the Labrador Sector of more than one Laurentide ice sheet. They are abundant Implications of the Dispersal of Belcher Islands Erratics. Géographie physique et across the Paleozoic terrain of the Hudson-James Bay lowland, but decrease in Quaternaire, 44(2), 113–136. https://doi.org/10.7202/032812ar abundance across the adjoining Archean upland. Similar erratics are common in northern Manitoba in the zone of confluence between Labrador and Keewatin Sector ice. Scattered occurences across the Prairies occur within the realm of south-flowing Keewatin ice. As these erratics are not known, and presumably not present, in Keewatin, they indicate redirection and deposition by Keewatin ice following one or more older advances of Labrador ice. The distribution of indicator erratics thus test our concepts of ice sheet growth. Tous droits réservés © Les Presses de l'Université de Montréal, 1990 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ Géographie physique et Quaternaire, 1990, vol. 44, n°2, p. 113-136, 29 fig., 1 tabl LAURENTIDE ICE-FLOW PATTERNS A HISTORIAL REVIEW, AND IMPLICATIONS OF THE DISPERSAL OF BELCHER ISLAND ERRATICS Victor K. PREST, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8. ABSTRACT This paper deals with the evo­ Archean upland. Similar erratics are common en se fondant sur la croissance glaciaire vers lution of ideas concerning the configuration of in northern Manitoba in the zone of confluence l'ouest à partir du Québec-Labrador. Ce con­ flow patterns of the great inland ice sheets between Labrador and Keewatin Sector ice. cept du dôme hudsonien a persisté, mais n'a east of the Cordillera. The interpretations of Scattered occurences across the Prairies pas été illustré avant 1977. Or, il apparaissait overall extent of Laurentide ice have changed occur within the realm of south-flowing d'ores et déjà à partir des différentes études little in a century (except in the Arctic) but the Keewatin ice. As these erratics are not known, menées sur la dispersion des glaces que la manner of growth, centres of outflow, and ice- and presumably not present, in Keewatin, they thèse du dôme unique n'était pas juste. Les flow patterns, remain somewhat controversial. indicate redirection and deposition by études sur la dispersion font état d'un Present geological data however, clearly Keewatin ice following one or more older écoulement glaciaire continu vers l'ouest, favour the notion of multiple centres of ice flow. advances of Labrador ice. The distribution of dans la partie sud de la baie d'Hudson et au The first map of the extent of the North indicator erratics thus test our concepts of ice delà, à partir du Québec, ainsi qu'un American ice cover was published in 1881. A sheet growth. écoulement vers l'est dans la partie nord de multi-domed concept of the ice sheet was illus­ la baie, à partir du Keewatin. La modélisation trated in an 1894 sketch-map of radial flow par ordinateur de l'Inlandsis laurentidien from dispersal areas east and west of Hudson RÉSUMÉ Historique des modes d'écoule­ démontre bien la complexité des écoulements Bay. The first large format glacial map of North ment de l'Inlandsis laurentidien et incidences glaciaires. La répartition de blocs erratiques America was published in 1913. The binary de la dispersion des blocs erratiques de l'ar­ indicateurs du groupe de la zone de plisse­ concept of the ice sheet was in vogue until chipel de Belcher. On traite ici de l'évolution ments d'âge protérozoïque de l'archipel de 1943 when a single centre in Hudson Bay was de la pensée en ce qui a trait à la configuration Belcher aide à préciser les modèles d'écou­ proposed, based on the westward growth of des grands mouvements glaciaires continen­ lement glaciaire. Ces errratiques ont large­ ice from Labrador/Québec. This Hudson taux à l'est de la Cordillère. Les interprétations ment été dispersés vers l'ouest, le sud-ouest dome concept persisted but was not illustrated quant à l'étendue de l'Inlandsis laurentidien et le sud à partir du secteur labradorien lors until 1977. By this time it was evident from dis­ ont peu changé depuis un siècle (sauf pour de plusieurs avancées de l'Inlandsis lauren­ persal studies that the single dome concept l'Arctique), mais les questions sur la crois­ tidien. Ils sont abondants dans les terrains was not viable. Dispersal studies clearly indi­ sance, les centres de dispersion et l'écoule­ paléozoïques des basses terres des baies de cate long-continued westward ice flow from ment glaciaire demeurent quelque peu contro­ James et d'Hudson, mais moins nombreux à Québec into and across southern Hudson versées. Les données géologiques actuelles, travers les hautes terres archéennes adjacen­ Bay, as well as eastward flow from Keewatin toutefois, tendent à confirmer la notion de tes. Des blocs erratiques semblables sont into the northern part of the bay. Computer- centres d'écoulement multiples. La première courants dans le nord du Manitoba dans la type modelling of the Laurentide ice sheet(s) carte montrant l'étendue de la couverture gla­ zone de confluence des glaces du Labrador further indicates their complex nature. The dis­ ciaire sur l'Amérique du Nord a été publiée en et du Keewatin. On trouve des blocs dispersés tribution of two indicator erratics from the 1881. Le concept d'un inlandsis à dômes mul­ à travers les Prairies dans la zone d'écoule­ Proterozoic-age Belcher Island Fold Belt tiples a été illustré dans une carte de 1894 ment des glaces du Keewatin vers le sud. En Group help constrain ice flow models. These montrant l'écoulement radial à partir de zones raison de leur absence probable au Keewatin, erratics have been dispersed widely to the de dispersion à l'est et à l'ouest de la baie ont croit qu'il y aurait eu un changement de west, southwest and south by the Labrador d'Hudson. La première grande carte glaciaire direction des glaces du Keewatin et dépôt Sector of more than one Laurentide ice sheet. de l'Amérique du Nord a été publiée en 1913. seulement après une ou plusieurs avancées They are abundant across the Paleozoic ter­ Le concept d'un inlandsis binaire a prévalu glaciaires antérieures en provenance du rain of the Hudson-James Bay lowland, but jusqu'en 1943, alors qu'on a mis de l'avant Labrador. La répartition des blocs erratiques decrease in abundance across the adjoining l'idée d'un seul centre dans la baie d'Hudson, indicateurs aide à éprouver les différents con­ cepts sur la croissance de l'inlandsis. Manuscrit reçu le 18 janvier 1989; manuscrit révisé accepté le 25 novembre 1989 114 V. K. PREST INTRODUCTION that produced these results must therefore have been contem­ poraneous with the transport of the drift over the surface — the The theory of continental glaciation was slow in gaining evidences afforded in Canada appear to favour the supposition acceptance in North America but the widespread distribution that they have been caused by the action of glaciers." of foreign stones was instrumental in its ultimate recognition.
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