Document generated on 09/24/2021 10:02 a.m. Géographie physique et Quaternaire Nature, Origin, and Age Relationships of Landscape Complexes in Southwestern Saskatchewan Les liens entre Ia nature, l’origine et l’âge des ensembles de paysages du sud-ouest de la Saskatchewan Beziehungen zwischen Natur, Ursprung und Alter von Landschaftseinheiten in Südwest-Saskatchewan Rudy W. Klassen Le 150e anniversaire de la Commision géologique du Canada Article abstract The 150th Anniversary of the Geological Survey of Canada Six landscape complexes are recognized in the Cypress Lake (72 F) and Wood Volume 46, Number 3, 1992 Mountain (72 G) areas of southwestern Saskatchewan. The complexes are recognized by their geomorphology, geology, and processes of landscape URI: https://id.erudit.org/iderudit/032920ar formation. The relationships of these components are used to determine the DOI: https://doi.org/10.7202/032920ar relative ages of the complexes. The oldest complex designated “unglaciated bedrock terrain”, consists of mature landscapes developed in Late Cretaceous and Tertiary sediments. It was formed by fluvial and mass wasting processes See table of contents under Late Tertiary arid to semi-arid climates. A rather similar complex, but with scattered drift residuals - chiefly glacial erratics, is called “bedrock terrain with residual drift”. This complex reflects similar Late Tertiary processes of Publisher(s) landscape formation but was later affected by Pleistocene glaciation. A complex called “bedrock terrain and drift” resembles the older complexes Les Presses de l'Université de Montréal except for a veneer of drift and local meltwater channels. Here, effects of the Late Wisconsinan glaciation are restricted to meltwater erosion, and the drift ISSN appears to predate this glaciation. The other three landscape complexes are: 0705-7199 (print) “first advance drift”, “interlobate drift” and “last advance drift”. These include 1492-143X (digital) terrain typical of the parts of the southern prairies covered by the Late Wisconsinan glacier. Explore this journal Cite this article Klassen, R. W. (1992). Nature, Origin, and Age Relationships of Landscape Complexes in Southwestern Saskatchewan. Géographie physique et Quaternaire, 46(3), 361–388. https://doi.org/10.7202/032920ar Tous droits réservés © Les Presses de l'Université de Montréal, 1992 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, 1992, vol. 46, n°3, p. 361-388, 31 fig., 1 tabl. NATURE, ORIGIN, AND AGE RELATIONSHIPS OF LANDSCAPE COMPLEXES IN SOUTHWESTERN SASKATCHEWAN* Rudy W. KLASSEN, Geological Survey of Canada, Terrain Sciences Division, 3303, 33 Street NW, Calgary, Alberta T2L 2A7. ABSTRACT Six landscape complexes are RÉSUMÉ Les liens entre Ia nature, l'ori­ ZUSAMMENFASSUNG Beziehungen zwis- recognized in the Cypress Lake (72 F) and gine et l'âge des ensembles de paysages du chen Natur, Ursprung und Alter von Lands- Wood Mountain (72 G) areas of southwest­ sud-ouest de la Saskatchewan. On observe chaftseinheiten in Sudwest-Saskatchewan. ern Saskatchewan. The complexes are rec­ six ensembles de paysages dans les régions Sechs Landschaftseinheiten wurden in den ognized by their geomorphology, geology, de Cypress Lake (72F) et Wood Mountain Gebieten von Cypress Lake (72 F) und Wood and processes of landscape formation. The (72G). Les ensembles se distinguent par leur Mountain (72 G) in Sùdwest-Saskatchewan relationships of these components are used géomorphologie, leur géologie et leurs pro­ identifiziert. Die Einheiten unterscheiden sich to determine the relative ages of the com­ cessus de formation. Les liens entre ces durch ihre Géomorphologie, Géologie und plexes. The oldest complex designated composantes ont servi à déterminer l'âge Prozesse der Landschaftsbildung. Die Bezie­ "unglaciated bedrock terrain", consists of relatif des paysages. L'ensemble le plus hungen zwischen diesen Komponenten wer- mature landscapes developed in Late ancien se caractérise par son substratum den benutzt, urn das relative Alter der Einhei­ Cretaceous and Tertiary sediments. It was non englacé et est composé de paysages au ten zu bestimmen. Die atteste Einheit, welche formed by fluvial and mass wasting proc­ stade de la maturité édifiés dans les sédi­ sich durch ihr nicht vereistes anstehendes esses under Late Tertiary arid to semi-arid ments du Crétacé supérieur et du Tertiaire. Gestein auszeichnet, besteht aus Land- climates. A rather similar complex, but with Il a été formé sous les climats arides à semi schaften im Stadium der Reife, die sich in scattered drift residuals — chiefly glacial arides du Tertiaire supérieur par des proces­ Sedimenten der spàten Kreidezeit und des erratics, is called "bedrock terrain with resid­ sus fluviatiles et de solifluxion. Le deuxième Tertiàr entwickelt haben. Sie wurde durch flu­ ual drift". This complex reflects similar Late ensemble est très semblable, mais com­ viale und Masse zerstôrende Vorgànge unter Tertiary processes of landscape formation prend, lui, des dépôts glaciaires résiduels den trockenen bis halbtrockenen Klimas des but was later affected by Pleistocene glacia­ dispersés, surtout de nature erratique. Cet spàten Tertiàr gebildet. Eine ziemlich àhnli- tion. A complex called "bedrock terrain and ensemble rappelle les mêmes processus de che Einheit, jedoch mit zerstreuten glazialen drift" resembles the older complexes except formation, mais il a été englacé au Pleis­ Ablagerungsruckstanden vor allem erratis- for a veneer of drift and local meltwater chan­ tocene. Le troisième ensemble caractérisé cher Natur, wird "Gebiet mit anstehendem nels. Here, effects of the Late Wisconsinan par ses dépôts glaciaires ressemble aux en­ Gestein und glazialen Ablagerungsruck­ glaciation are restricted to meltwater ero­ sembles plus anciens, sauf en ce qui a trait standen" genannt. Diese Einheit spiegelt sion, and the drift appears to predate this gla­ au placage de matériel détritique et à la pré­ àhnliche Prozesse der Landschaftsbildung ciation. The other three landscape com­ sence de chenaux de fonte. Ici, les effets de im spàten Tertiàr, wurde aber spàter durch plexes are: "first advance drift", "interlobate la glaciation du Wisconsinien supérieur se die Vereisung im Pleistozàn beeinfluRt. Ein drift" and "last advance drift". These include limitent à une érosion par l'eau de fonte, car Gebiet mit anstehendem Gestein und AbIa- terrain typical of the parts of the southern les dépôts glaciaires semblent antérieurs à gerungen gleicht den àlteren Einheiten, prairies covered by the Late Wisconsinan cette glaciation. Les trois autres ensembles abgesehen von einem Schleier von Trumme- glacier. de paysages se caractérisent, respective­ rablagerungen und ortlichen Schmelzwas- ment, par des dépôts glaciaires de première serkanàlen. Hier scheinen die Auswirkungen avancée, par des dépôts glaciaires interlo- der spàt-Wisconsinischen Vereisung sich auf baires et, enfin, par des dépôts glaciaires de Erosion durch Schmelzwasser zu beschràn- dernière avancée. Ces paysages renferment ken, und die glazialen Ablagerungen schei­ des terrains caractéristiques des milieux de nen vor dieser Vereisung geschehen zu sein. la Prairie englacés au Wisconsinien Die drei anderen Landschaftseinheiten sind: supérieur. "glaziale Ablagerungen des ersten Vors- tofies", "interlobale glaziale Ablagerungen" und "glaziale Ablagerungen des letzten VorstoBes". Diese Landschaftseinheiten sch- lieBen Formationen ein, die typisch fur die im spàten Wisconsinum vereisten Teile der Prà- rien sind. * Geological Survey of Canada Contribution No. 35992 Manuscrit reçu le 26 février 1992; manuscrit révisé accepté le 19 octobre 1992 362 R. W. KLASSEN INTRODUCTION Field work included the description and sampling of road GENERAL STATEMENT cuts, natural exposures, drill holes (10 to 15 m deep) and backhoe trenches. Information for the drift thickness maps A panorama of prairie scenery unique to the Cypress Hills came mainly from published maps and reports, along with a and Wood Mountain uplands of southwestern Saskatchewan large body of unpublished data obtained from government includes plateau remnants with north-facing escarpments agencies. Published maps and reports based on extensive and southward sloping pediments separated by broad, gen­ field and subsurface studies (Frazer et al., 1935; Furnival, erally southward trending valleys. Parts of the higher plateaus 1946; Whitaker, 1965,1968; Williams, 1929), provided more and steep slopes of the Cypress Hills sustain a substantial than adequate information on the bedrock geology and cover of pine, spruce and poplar, in contrast to the open aspects of the physiography of the region. Surficial geology grasslands common to other parts of these uplands. maps of the Cypress Lake (72F) and Wood Mountain (72G) Unglaciated plateau remnants found on the highest part areas on a scale of 1: 250,000 (Klassen, 1991, 1992) pro­ (West Block) of the Cypress Hills and the southeastern part vided the bases for establishing the nature of the deposits of the Wood Mountain Upland are unique to this part