Quaternary geology of the Grand Rapids area, Manitoba

1970 ◽  
Vol 7 (3) ◽  
pp. 853-857 ◽  
Author(s):  
R. H. Grice
Keyword(s):  
Quaternary Geology ◽  
Stream Channels ◽  
Drainage Pattern ◽  
Lake Agassiz ◽  
Quaternary Deposits ◽  
Lake Winnipeg ◽  
Grand Rapids ◽  
Central Canada ◽  
History Of ◽  
Western Side

Grand Rapids is at the mouth of the Saskatchewan River on the western side of Lake Winnipeg in central Canada and is in the western part of the region formerly covered by Glacial Lake Agassiz.Relict beaches and cliffs, and abandoned spillway and stream channels have been observed in the area. Much of the Paleozoic bedrock is covered by Quaternary deposits consisting of three or four Wisconsin tills interspersed and covered by glacio–lacustrine silts and clays.The events are correlated with the final four episodes in the general history of Lake Agassiz and it appears that after substantial changes in the drainage pattern, the recent course of the lower reaches of the Saskatchewan River developed during the last 8 000 ± 250 y.

Holocene evolution of the Assiniboine River paleochannels and Portage la Prairie alluvial fan

1989 ◽  
Vol 26 (9) ◽  
pp. 1834-1841 ◽  
Author(s):  
W. F. Rannie ◽  
L. H. Thorleifson ◽  
J. T. Teller
Keyword(s):  
Alluvial Fan ◽  
Red River ◽  
Lake Agassiz ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Sediment Loads ◽  
History Of ◽  
Western Side

The Portage la Prairie alluvial fan was constructed by numerous successive paleochannels of the Assiniboine River along the western side of the Lake Agassiz basin as the level of the lake rapidly declined beginning 9500 years ago. The history of the paleochannels during the first several thousand years is not known. Paleochannel morphologies and cross-cutting relations, soil maturity, and radiocarbon dates, however, indicate that by 6000–7000 years ago flow was northward into Lake Manitoba. This direction was maintained until about 3000 years ago, when avulsion redirected the Assiniboine eastward to the Red River near Winnipeg. The morphologies of the paleochannels suggest that channel-forming discharges and sediment loads of the ancestral rivers have not differed significantly from the modern values despite palynological evidence that the climate was warmer and drier during much of the Holocene.

scholarly journals Multilocus phylogeny and historical biogeography of Hypostomus shed light on the processes of fish diversification in La Plata Basin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yamila P. Cardoso ◽  
Luiz Jardim de Queiroz ◽  
Ilham A. Bahechar ◽  
Paula E. Posadas ◽  
Juan I. Montoya-Burgos
Keyword(s):  
Middle Miocene ◽  
Drainage Pattern ◽  
Ecological Diversification ◽  
La Plata ◽  
La Plata Basin ◽  
History Of ◽  
Dispersal Corridors ◽  
Shed Light ◽  
Strong Barrier ◽  
Multilocus Phylogeny

AbstractDistribution history of the widespread Neotropical genus Hypostomus was studied to shed light on the processes that shaped species diversity. We inferred a calibrated phylogeny, ancestral habitat preference, ancestral areas distribution, and the history of dispersal and vicariance events of this genus. The phylogenetic and distribution analyses indicate that Hypostomus species inhabiting La Plata Basin do not form a monophyletic clade, suggesting that several unrelated ancestral species colonized this basin in the Miocene. Dispersal to other rivers of La Plata Basin started about 8 Mya, followed by habitat shifts and an increased rate of cladogenesis. Amazonian Hypostomus species colonized La Plata Basin several times in the Middle Miocene, probably via the Upper Paraná and the Paraguay rivers that acted as dispersal corridors. During the Miocene, La Plata Basin experienced marine incursions, and geomorphological and climatic changes that reconfigured its drainage pattern, driving dispersal and diversification of Hypostomus. The Miocene marine incursion was a strong barrier and its retraction triggered Hypostomus dispersal, increased speciation rate and ecological diversification. The timing of hydrogeological changes in La Plata Basin coincides well with Hypostomus cladogenetic events, indicating that the history of this basin has acted on the diversification of its biota.

The Quaternary Deposits at Hoxne, Suffolk, and their Archaeology

1955 ◽  
Vol 20 (2) ◽  
pp. 131-154 ◽  
Author(s):  
R. G. West ◽  
C. M. B. McBurney
Keyword(s):  
Eighteenth Century ◽  
Quaternary Deposits ◽  
Direct Association ◽  
History Of ◽  
Lake Deposits ◽  
Important Site

The long history of investigations at Hoxne, Suffolk, beginning when John Frere discovered Palaeolithic implements there in the last decade of the eighteenth century, has been described by Moir. Moir himself worked on the deposits at Hoxne, and the results of his investigations, together with those of Reid, have formed the basis for our knowledge of the geology and archaeology of the deposits. From these investigations it is clear that Hoxne is an important site, for it is one of the rare places where there are interglacial lake deposits and Palaeolithic implements in direct association with ground moraines of the older glaciations. Moreover, the deposits occupy a well-known position in the East Anglian Quaternary succession.

Late Wisconsinan glacial stratigraphy and history of southeastern Manitoba

1980 ◽  
Vol 17 (1) ◽  
pp. 19-35 ◽  
Author(s):  
James T. Teller ◽  
Mark M. Fenton
Keyword(s):  
Carbonate Rocks ◽  
Lacustrine Sediment ◽  
Precambrian Rock ◽  
Lake Agassiz ◽  
Rock Fragments ◽  
Lithostratigraphic Units ◽  
Stratigraphic Position ◽  
History Of ◽  
International Boundary ◽  
Late Wisconsinan

The history of Late Wisconsinan glaciation in southwestern Manitoba has been established by identifying and correlating ice-laid lithostratigraphic units in the subsurface. Five Late Wisconsinan tills are defined on the basis of their texture, mineralogic composition, and stratigraphic position. These new formations are, from youngest to oldest, Marchand, Whitemouth Lake, Roseau, Senkiw, and Whiteshell Formations.Late Wisconsinan ice first invaded southeastern Manitoba 22 000 to 24 000 years ago. This Laurentide glacier advanced from the northeast across the Precambrian Shield and deposited the sandy Whiteshell and Senkiw tills, which contain abundant Precambrian rock fragments and minerals and few Paleozoic carbonate grains. Shortly after this, Keewatin ice advanced from the northwest over Paleozoic carbonate rocks, depositing the loamy carbonate-rich Roseau Formation throughout most of the area. This ice remained over southeastern Manitoba until after 13 500 years ago, when it rapidly retreated northward with Lake Agassiz on its heels. Two brief glacial readvances occurred. The first overrode Lake Agassiz lacustrine sediment as far south as central North Dakota shortly after about 13 000 years ago. The clayey Whitemouth Lake till was deposited in southern Manitoba at this time. After a rapid retreat, the ice briefly pushed southward over southeastern Manitoba about 12 000 years ago to just south of the International Boundary. The sandy carbonate-rich Marchand Formation was deposited at this time as the ice overrode its own sandy outwash. By 11 000 years ago, ice had disappeared from southeastern Manitoba.

James C. Knox (1977) Human impacts on Wisconsin stream channels. Annals of the Association of American Geographers 67: 224–244.

2013 ◽  
Vol 37 (3) ◽  
pp. 422-431 ◽  
Author(s):  
William L. Graf
Keyword(s):  
Mississippi River ◽  
Human Impacts ◽  
Professional Community ◽  
River System ◽  
Stream Channels ◽  
Early 19Th Century ◽  
Driftless Area ◽  
University Of Wisconsin ◽  
History Of ◽  
Floodplain Deposits

James C. Knox’s 1977 paper “Human Impacts on Wisconsin Stream Channels,” published in the Annals of the Association of American Geographers, was a key component of a suite of three papers by him defining the response of rivers to the introduction and management of agriculture and to climate change. In this paper he used the Driftless Area of southwest Wisconsin as a laboratory where he could define fluvial responses by their sedimentary signatures in floodplain deposits. Land-use records dating back to the early 19th century along with shorter climate records provided his understanding of the drivers of change. He found that floods increased as an outcome of land-cover change. Upstream tributaries became wider and shallower as coarse deposits limited their adjustments, while main stem channels became narrower and deeper. His paper reflected the influence of his graduate advisor and especially of prominent faculty colleagues at the University of Wisconsin from fields ranging from soils and climatology to geomorphology and history. The paper was the subject of considerable debate in the professional community, but it remains a much-cited example of Knox’s work in unraveling the Quaternary and Holocene history of rivers of the Driftless Area and by extension the upper Mississippi River system.

Postglacial Diatom Stratigraphy in Relation to the Recession of Glacial Lake Agassiz

1975 ◽  
Vol 5 (4) ◽  
pp. 529-540 ◽  
Author(s):  
J.C. Ritchie ◽  
L.K. Koivo
Keyword(s):  
Sandy Beach ◽  
Sedimentary Environment ◽  
Glacial Lake ◽  
Lake Agassiz ◽  
Organic Detritus ◽  
Sedimentary Environments ◽  
Grand Rapids ◽  
Glacial Lake Agassiz ◽  
Diatom Stratigraphy ◽  
Beach Sands

The sediment and diatom stratigraphy of a small pond on The Pas moraine, near Grand Rapids, Manitoba, reveals a change in sedimentary environment related directly to the last stages of Glacial Lake Agassiz. Beach sands were replaced by clay 7300 14C y. a., then by organic silt and, at 4000 14C y. a. by coarse organic detritus; the corresponding diatom assemblages were (I) a predominantly planktonic spectrum in beach sands, (II) a rich assemblage of nonplanktonic forms, and (III) a distinctly nonplanktonic acidophilous spectrum. These results confirm Elson's (1967) reconstruction of the extent and chronology of the final (Pipun) stage of Glacial Lake Agassiz. The sedimentary environments change from a sandy beach of a large lake at 7300 BP to a small, shallow eutrophic pond with clay and silt deposition from 7000 to 4000 BP. From 4000 BP to the present, organic detritus was deposited in a shallow pond that tended toward dystrophy.

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