scholarly journals The Cordilleran Ice Sheet: One Hundred and Fifty Years of Exploration and Discovery

2007 ◽  
Vol 45 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Lionel E. Jackson, ◽  
John J. Clague
Keyword(s):  
World War Ii ◽  
Research Effort ◽  
Ice Sheet ◽  
Early Period ◽  
Transitional Period ◽  
Marine Geology ◽  
Ice Sheet Dynamics ◽  
Cordilleran Ice Sheet ◽  
Regional Fluctuations ◽  
Glacial Landforms

ABSTRACT Present concepts about the Cordilleran Ice Sheet are the product of observations and ideas of several generations of earth scientists. The limits of glaciation in the Cordillera were established in the last half of the nineteenth century by explorers and naturalists, notably G. M. Dawson, R. G. McConnell, and T. C. Chamberlin. By the turn of the century, the gross configuration of the Cordilleran Ice Sheet had been determined, but the causes of glaciation and ice-sheet dynamics remained poorly understood. This early period of exploration and discovery was followed by a transitional period, from about 1900 to 1950, during which a variety of glacial landforms and deposits were explained (e.g., Channeled Scablands of Washington; "white silts" of southern British Columbia), and conceptual models of the growth and decay of the ice sheet were proposed. Shortly after World War II, there was a dramatic increase in research into all aspects of glaciation in the Canadian Cordillera which has continued unabated to the present. Part of the research effort during this period has been directed at resolving the Cordilleran Ice Sheet in both time and space. Local and regional fluctuations of the ice sheet have been reconstructed through stratigraphie and sedimentological studies, supported by radiocarbon and other dating techniques. Compilations of late Pleistocene ice-flow directions have shown that the Cordilleran Ice Sheet was a mass of coalescent glaciers flowing in a complex fashion from many montane source areas. During the postwar period, research has also begun or advanced significantly in several other disciplines, notably glaciology, process sedimen-tology, geomorphology, paleoecology, and marine geology. Attempts are now being made to quantitatively model the Cordilleran Ice Sheet using computers and the geological database assembled by past generations of earth scientists.

scholarly journals Past Ice-Sheet Behaviour: Retreat Scenarios and Changing Controls in the Ross Sea, Antarctica

2016 ◽  
Author(s):  
Anna Ruth Halberstadt ◽  
Lauren M. Simkins ◽  
Sarah L. Greenwood ◽  
John B. Anderson
Keyword(s):  
Drainage Basin ◽  
Ross Sea ◽  
Ice Sheet ◽  
Small Scale ◽  
Swath Bathymetry ◽  
Geomorphic Features ◽  
Ice Sheet Dynamics ◽  
Lift Off ◽  
Glacial Landforms ◽  
Western Ross Sea

Abstract. Studying the history of ice-sheet behaviour in Antarctica's largest drainage basin, the Ross Sea, can improve our understanding of patterns, timing, and controls on marine-based ice-sheet dynamics, and provide constraints on numerical ice-sheet models. Newly collected high-resolution multibeam swath bathymetry data, combined with two decades of legacy multibeam and seismic data, are used to map glacial landforms and reconstruct paleodrainage. Last Glacial Maximum grounded ice reached the continental shelf edge in the eastern but not western Ross Sea. Recessional geomorphic features in the western Ross Sea indicate virtually continuous retreat of the ice sheet in contact with the bed. In the eastern Ross Sea, well-preserved linear features and a lack of small-scale recessional landforms record rapid lift-off of grounded ice from the bed. Physiography exerted a first-order control on ice behaviour, while seafloor geology played an important subsidiary role. Previously published grounding-line retreat scenarios are based on terrestrial observations; however, this study uses Ross Sea-wide geomorphology to constrain marine deglaciation. Our analysis of retreat patterns suggests that: (1) a large embayment formed in the eastern Ross Sea; (2) retreat was complex and asynchronous between troughs; and (3) the eastern Ross Sea largely deglaciated prior to the western Ross Sea.

scholarly journals Submarine glacial landforms record Late Pleistocene ice-sheet dynamics, Inner Hebrides, Scotland

2015 ◽  
Vol 123 ◽  
pp. 76-90 ◽  
Author(s):  
Dayton Dove ◽  
Riccardo Arosio ◽  
Andrew Finlayson ◽  
Tom Bradwell ◽  
John A. Howe
Keyword(s):  
Late Pleistocene ◽  
Ice Sheet ◽  
Ice Sheet Dynamics ◽  
Glacial Landforms

The deglacial dynamics of the Laurentide and Cordilleran ice sheets in the Mackenzie Mountains, Northwest Territories, Canada

2021 ◽  
Author(s):  
Benjamin J Stoker ◽  
Martin Margold ◽  
Duane G. Froese ◽  
John C. Gosse
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Geomorphological Mapping ◽  
Dating Methods ◽  
Mountain Front ◽  
Modelling Studies ◽  
Mackenzie Mountains ◽  
Cordilleran Ice Sheet ◽  
The Individual ◽  
Glacial Landforms

<p>The northwestern sector of the Laurentide Ice Sheet coalesced with the Cordilleran Ice Sheet over the southern Mackenzie Mountains, and with local montane glaciers along the eastern slopes of the Mackenzie Mountains. Numerical modelling studies have identified rapid ice sheet thinning in this region as a major contributor to Meltwater Pulse 1A. Despite advances in remote sensing and numerical dating methods, the configuration and chronology of the northwestern sector of the Laurentide Ice Sheet have not been reconstructed in detail. The last available studies date back to the 1990s, when field surveys and mapping from aerial imagery were used to reconstruct the glacial history in the Mackenzie Mountains. Cross-cutting relations between glacial landforms and a series of <sup>36</sup>Cl cosmogenic nuclide dates were used to propose a deglacial model involving a significant readvance of the Laurentide Ice Sheet in the region. However, the chronological evidence supporting the readvance is uncertain because the individual ages are few and poorly clustered. Here we present an updated map of the glacial limits during the local Last Glacial Maximum and the recessional record in the Mackenzie Mountains, based on glacial geomorphological mapping from the ArcticDEM. We provide sixteen new <sup>10</sup>Be dates from four sites that were previously glaciated by the Laurentide Ice Sheet to constrain the deglacial sequence across the region. These dates indicate ice sheet detachment from the eastern Mackenzie Mountains at ~16 ka as summits in the mountain front became ice-free. The Mackenzie Valley at ~ 65 °N became ice-free at ~ 14 – 13  ka, towards the end of the Bølling-Allerød warm period. Combining these dates with existing <sup>10</sup>Be dates, these chronological constraints on the deglaciation of the Laurentide Ice Sheet allow us to reinterpret landform relations in the Mackenzie Mountains in order to reconstruct the ice sheet retreat. Our reconstruction provides updated constraints on the LGM extent, and the timing and pattern of deglaciation in the Mackenzie Mountains. This new understanding is useful to future efforts to quantify past sea-level contributions from the western Laurentide Ice Sheet.</p>

NORTHERN CORDILLERAN ICE SHEET DISPLAYS A DIACHRONOUS RESPONSE TO MIS 4 FORCING, YUKON TERRITORY,CANADA

2019 ◽  
Author(s):  
Brent C. Ward ◽  
◽  
Jeffrey D. Bond ◽  
Derek Cronmiller ◽  
Derek Turner ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Yukon Territory ◽  
Cordilleran Ice Sheet
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