scholarly journals Ice-flow history of the Laurentide Ice Sheet in the southwest Northwest Territories: a Shield to Cordillera transect

2019 ◽  
Author(s):  
R C Paulen ◽  
I R Smith ◽  
M Ross ◽  
G W Hagedorn ◽  
J M Rice
Keyword(s):  
Northwest Territories ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Ice Flow ◽  
History Of

scholarly journals Glacial and Sea Level History of Lowther and Griffith Islands, Northwest Territories: A Hint of Tectonics

2007 ◽  
Vol 47 (2) ◽  
pp. 133-145 ◽  
Author(s):  
Arthur S. Dyke
Keyword(s):  
Northwest Territories ◽  
Sea Level ◽  
Ice Sheet ◽  
Canadian Arctic ◽  
Laurentide Ice Sheet ◽  
Structural Elements ◽  
Ice Flow ◽  
Ice Load ◽  
Last Glaciation ◽  
History Of

ABSTRACT Lowther and Griffith islands, in the centre of Parry Channel, were overrun by the Laurentide Ice Sheet early in the last glaciation. Northeastward Laurentide ice flow persisted across at least Lowther Island until early Holocene déglaciation. Well constrained postglacial emergence curves for the islands confirm a southward dip of raised shorelines, contrary to the dip expected from the ice load configuration. This and previously reported incongruities may indicate regionally extensive tectonic complications of postglacial rebound aligned with major structural elements in the central Canadian Arctic Islands.

Landform assemblages produced by the Laurentide Ice Sheet in northeastern British Columbia and adjacent Northwest Territories — constraints on glacial lakes and patterns of ice retreatThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 593-610 ◽  
Author(s):  
Jan M. Bednarski
Keyword(s):  
British Columbia ◽  
Northwest Territories ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Ice Flow ◽  
The North ◽  
Relative Chronology ◽  
Mountain Front ◽  
Ice Retreat ◽  
Cordilleran Ice Sheet

The Laurentide Ice Sheet reached the Canadian Cordillera during the last glacial maximum in northeastern British Columbia and adjacent Northwest Territories and all regional drainage to unglaciated areas in the north was dammed by the ice. Converging ice-flow patterns near the mountain front suggest that the Laurentide Ice Sheet likely coalesced with the Cordilleran Ice Sheet during the last glaciation. With deglaciation, the ice masses separated, but earlier ice retreat in the south meant that meltwater pooled between the mountain front and the Laurentide margin. The level of the flooding was controlled by persistent ice cover on the southern Franklin Mountains. Glacial Lake Liard formed when the Laurentide Ice Sheet retreated east of the southern Liard Range and, at its maximum extent, may have impounded water at least as far south as the Fort Nelson River. Deglaciation of the plains was marked by local variations in ice flow caused by a thin ice sheet becoming more affected by the topography and forming lobes in places. These lobes caused diversions in local drainage readily traced by abandoned meltwater channels. Radiocarbon ages from adjacent areas suggest the relative chronology of deglaciation presented here occurred between 13 and 11 ka BP.

scholarly journals Surficial geology, northeastern Cameron Hills, Northwest Territories, NTS 85-C/3, 4, 5, and 6

2021 ◽  
Author(s):  
I R Smith ◽  
R C Paulen ◽  
G W Hagedorn
Keyword(s):  
Northwest Territories ◽  
Sea Level ◽  
Ice Sheet ◽  
Alluvial Fan ◽  
Laurentide Ice Sheet ◽  
Ice Flow ◽  
Boreal Plains ◽  
Surficial Geology ◽  
Sediment Cover

The northeastern Cameron Hills comprise a Cretaceous bedrock upland, rising >550 m above the regional boreal plains. It was inundated by the Laurentide Ice Sheet and includes much of a prominent 60 by 20 km southwest-oriented mega-scale glacial lineation field, formed in thick till. Subsequent ice flow on northeast Cameron Hills occurred north to south, and a series of lobate and ice-thrust moraines suggest glacial surging. Rotational bedrock slumps cover the eastern and northern flanks of Cameron Hills, and extensive alluvial fan deposits draining from these slopes blanket the surrounding topography. The Cameron River formed as a glacial spillway, draining southwest across the upland before turning north and draining into Tathlina Lake. An expansive raised delta and glaciolacustrine sediment cover extending up to ~295 m above sea level, south of Tathlina Lake, records impoundment of an ice-marginal lake between the northeastward-retreating Laurentide Ice Sheet and Cameron Hills.

Glacial dispersal of rock debris in central Gaspésie, Quebec, Canada

1993 ◽  
Vol 30 (8) ◽  
pp. 1697-1707 ◽  
Author(s):  
Rémi Charbonneau ◽  
Peter P. David
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial History ◽  
Dispersal Pattern ◽  
Glacial Erosion ◽  
Ice Flow ◽  
Granite Pluton ◽  
Alpine Glacier ◽  
History Of ◽  
Late Wisconsinan

The lithological content of tills in central Gaspésie is evaluated by pebble counting of 231 samples collected in excavation pits and containing 200 pebbles each. The results are used here to establish the pattern of debris dispersal and to infer the glacial history of the area. The dispersal pattern is characterized by well-defined southeasterly (160–170°) and northeasterly (40–60°) trending trains. Half-distance values of glacial transport along the trains range from 5 to 9 km for both directions, suggesting ice flow events of considerable magnitude. The volume of material in the trains represents 1–6 m of glacial erosion of the bedrock. Glacial cirques and short U-shaped valleys, about 100–200 m deep, are incised into the McGerrigle Mountains granite pluton as well as the adjacent metabasalt. The corresponding trains are aligned with these erosional features, indicating that their clast content was derived from those features during an early Alpine Glacier Phase. The southeasterly trending dispersal trains are associated with an invasion of central Gaspésie by the Laurentide Ice Sheet during the Early Wisconsinan, whereas the northeasterly trending trains are associated with a local centre of outflow over Gaspésie during the Late Wisconsinan.

scholarly journals Objective Reconstructions of the Late Wisconsinan Laurentide Ice Sheet and the Significance of Deformable Beds

2007 ◽  
Vol 39 (3) ◽  
pp. 229-238 ◽  
Author(s):  
D. A. Fisher ◽  
N. Reeh ◽  
K. Langley
Keyword(s):  
Yield Stress ◽  
Flow Direction ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Ice Streams ◽  
Ice Flow ◽  
Surface Slopes ◽  
Late Wisconsinan

ABSTRACT A three dimensional steady state plastic ice model; the present surface topography (on a 50 km grid); a recent concensus of the Late Wisconsinan maximum margin (PREST, 1984); and a simple map of ice yield stress are used to model the Laurentide Ice Sheet. A multi-domed, asymmetric reconstruction is computed without prior assumptions about flow lines. The effects of possible deforming beds are modelled by using the very low yield stress values suggested by MATHEWS (1974). Because of low yield stress (deforming beds) the model generates thin ice on the Prairies, Great Lakes area and, in one case, over Hudson Bay. Introduction of low yield stress (deformabie) regions also produces low surface slopes and abrupt ice flow direction changes. In certain circumstances large ice streams are generated along the boundaries between normal yield stress (non-deformable beds) and low yield stress ice (deformabie beds). Computer models are discussed in reference to the geologically-based reconstructions of SHILTS (1980) and DYKE ef al. (1982).

scholarly journals Formational history of the Wicklow Trough: a marine‐transgressed tunnel valley revealing ice flow velocity and retreat rates for the largest ice stream draining the late‐Devensian British–Irish Ice Sheet

2020 ◽  
Vol 35 (7) ◽  
pp. 907-919 ◽  
Author(s):  
Mark Coughlan ◽  
Zsuzsanna TÓth ◽  
Katrien J. J. Van Landeghem ◽  
Stephen Mccarron ◽  
Andrew J. Wheeler
Keyword(s):  
Flow Velocity ◽  
Ice Sheet ◽  
Ice Flow ◽  
Ice Stream ◽  
History Of

scholarly journals Ice Streams of the Laurentide Ice Sheet

2006 ◽  
Vol 58 (2-3) ◽  
pp. 269-280 ◽  
Author(s):  
Monica C.M. Winsborrow ◽  
Chris D. Clark ◽  
Chris R. Stokes
Keyword(s):  
Aerial Photography ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Major Influence ◽  
Ice Streams ◽  
Spatial Organisation ◽  
Ice Flow ◽  
Strength Of Evidence ◽  
Fast Ice ◽  
The Stability

Abstract Ice streams had a major influence on the configuration and the stability of the Laurentide Ice Sheet. Their identification is crucial for an understanding of ice sheet behaviour and their importance is reflected by the recent increase in paleo-ice stream research. This paper provides a synopsis of Laurentide paleo-ice streams, compiled from published sources and our mapping from satellite imagery and aerial photography. In total, 49 hypothesised ice streams are reviewed, and categorised according to the strength of evidence for streaming and knowledge of their extent. A map of Laurentide paleo-ice streams is presented, along with tables documenting the nature of evidence on which streaming behaviour has been invoked. The distribution of ice streams demonstrates the spatial organisation of fast ice flow, and overlapping imprints document major changes in ice flow during retreat. We note that Laurentide paleo-ice streams exhibit a much greater range in size than those currently operating in Antarctica.

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