Quaternary geology and geomorphology of Assiniboine and Qu'Appelle valleys of Manitoba and Saskatchewan

Klassen, R. A.

doi:10.4095/103988

Cited by 19 publications

(22 citation statements)

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“…The most detailed recent work in the area is by Klassen (1975), and 1 have followed his suggested reconstruction of the glacial history in the broad outline of events sketched here. However, it must be stressed that no attempt is made to discern precise locations for ice fronts or glacial lake margins, and the positions shown in Fig.…”

Section: P/1ysiogrc~/~i7y Ancl Pleistocene Geolog)~mentioning

confidence: 98%

“…As the ice melted, one large and several small glacial lakes formed between the ice sheet and various topographic highs. The history of the large lake, ~l a c i a l L. Agassiz, was complex, involving several stages of expansion and diminution, worked out partially by Elson (1967), Prest (1970), and Klassen (1975). Extensive lacustrine deposits, wave-modified drift, beaches, and deltas characterize the area occupied by these glacial lakes.…”

Section: P/1ysiogrc~/~i7y Ancl Pleistocene Geolog)~mentioning

confidence: 98%

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The late-Quaternary vegetational history of the Western Interior of Canada

Ritchie¹

1976

Can. J. Bot.

137

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The late-Wisconsinan pollen stratigraphy of the Western Interior of Canada is assembled and 16 representative sites provide a basis for establishing trends of vegetation history. Sites in the southern, prairie region show an early Picea–Artemisia assemblage (12 × 103 to 10 × 103) replaced by a zone dominated by herb pollen. Similarly, sites in the Aspen Parkland and Transitional zones all have the Picea–Artemisia zone from as early as 13.9 × 103 to 10 × 103, followed by a herb zone. It is replaced by an arboreal pollen zone at 4.5 × 103 to 3 × 103 B.P. While there is a broad trend common to all sites in the modern boreal forest, from an early spruce-dominated assemblage to a late postglacial spruce–pine–birch assemblage identical with modern spectra, there are differences in the details of stratigraphy. Two sites in central Alberta have a poplar zone preceding the early spruce zone. Sites near the modern southern forest boundary show a late development (3 × 103 B.P.) of the mixed boreal forest from prairie and hardwood deciduous forest communities. One site, at Flin Flon, Saskatchewan, provides clear evidence for a treeless episode (Artemisia–grass–sedge) preceding the spruce zone.As the late-Wisconsinan glacial ended, an early version of the boreal forest, dominated by spruce and lacking pine, spread from adjacent U.S. on to deglaciated surfaces and till over stagnant ice. It persisted in the southern part of the area until about 10 × 103 and until 6 × 103 in the northernmost portions. In the south the spruce forest was replaced directly by prairie, spreading from the southwest and extending farther north than its modern limit between 7.5 × 103 and 6 × 103. All remnants of ice sheets and glacial lakes had disappeared by about 7 × 103 and the northern part of the area was occupied by a boreal forest undergoing rapid changes in composition from the early spruce-dominated version to the mixed spruce–pine–birch–poplar mosaic prevalent today. Pine probably spread from western réfugia, at least into areas north and west of L. Winnipeg. At about 3 × 103 the southern limit of the forest extended to the south, apparently in response to a climate with cooler and (or) wetter growing seasons. The rapid replacement of the spruce-dominated boreal forest by grasslands in the early postglacial was probably a response to warmer and drier growing seasons.

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Section: P/1ysiogrc~/~i7y Ancl Pleistocene Geolog)~mentioning

confidence: 98%

Section: P/1ysiogrc~/~i7y Ancl Pleistocene Geolog)~mentioning

confidence: 98%

The late-Quaternary vegetational history of the Western Interior of Canada

Ritchie¹

1976

Can. J. Bot.

137

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“…'Assiniboine vers le nord. (Klassen, 1972(Klassen, , 1975Welch, 1973;Nielsen, 1988) have been the focus of relatively few studies in spite of the potential of terraces to provide "one of the best geomorphic indicators of Holocene environmental changes" (Rains and Welch, 1988, p. 454). The complex sequence of Holocene alluvial sediments exposed along the Red River of southern Manitoba (Fig.…”

mentioning

confidence: 99%

Fluvial Sedimentology and Paleoecology of Holocene Alluvial Deposits, Red River, Manitoba

Nielsen¹,

McKillop²,

Conley³

2007

gpq

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Stratigraphie and paleoecological analyses at five sections, together with age determinations based on 19 previously published and 21 new radiocarbon dates, provide a detailed late Holocene history of the Red River, Manitoba. Ecological information, such as age frequency analysis, relative abundance, diversity and association of species was drawn from 19 mollusc species. These data indicate that the Red and Assiniboine rivers cut the valleys they occupy today within a thousand years of the regression of Lake Agassiz. In the south, up to 14 m of alluvium has accumulated during the last 7000 years. A decrease in the sedimentation rate at 1400 BP is coincident with the shift in the position of the Assiniboine from the valley of the La Salle River to its present position. Overbank sedimentation did not start in the northern part of the area until ca. 5200 BP. Initial rapid sedimentation rates in this area are attributed to increased precipitation and a brief eastward excursion of the Assiniboine River into the Red. In spite of increased precipitation, flood frequencies remained low in the north until 1400 BP. Increased overbank sedimentation after 1400 BP is attributed to the northward shift in the position ot the Assiniboine.

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“…3). Even (Christiansen 1960;Christiansen et al 1977;Klassen 1975 Buffalo Pound. the first lake encountered along the southeast course of the River (Fig.…”

Section: Sediments and Soilsmentioning

confidence: 99%