scholarly journals Deglaciation of the Cordillera of Western Canada at the end of the Pleistocene

2017 ◽  
Vol 43 (2) ◽  
pp. 449 ◽  
Author(s):  
J.J. Clague
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Ice Cover ◽  
High Elevation ◽  
Coast Mountains ◽  
Western Margin ◽  
Warming Climate ◽  
Glacier Ice ◽  
Cordilleran Ice Sheet ◽  
Exposure Ages

Nearly all of what is now British Columbia and adjacent areas were covered by an ice sheet at the maximum of the Last Glaciation (MIS 2) about 18,000 years ago. By 11,000 years ago, the Cordilleran Ice Sheet had disappeared, a victim of warming climate, eustatic sea-level rise along its western margin, and perhaps a reduction in precipitation. Deglaciation proceeded by frontal retreat at the periphery of the ice sheet and by downwasting, complex frontal retreat, and localized stagnation in its interior areas. The chronology of deglaciation is constrained, albeit with inherent dating errors, by AMS radiocarbon and 10Be surface exposure ages. High-elevation sites at the western margin of the British Columbia Interior Plateau, east of the Coast Mountains, became ice-free between about 15,000 and 12,000 years ago. Ice cover in the southern Coast Mountains was sufficiently extensive during the Younger Dryas Chronozone (12,900-11,700 years ago) that glaciers advanced into low-lying areas north and east of Vancouver. At the same time, however, a labyrinth of dead or dying tongues of glacier ice covered some interior valleys. By 11,000 years ago, ice cover in the Canadian Cordillera was no more extensive than it is today.

Advance of the Late Wisconsin Cordilleran Ice Sheet in Southern British Columbia Since 22,000 Yr B.P.

1980 ◽  
Vol 13 (3) ◽  
pp. 322-326 ◽  
Author(s):  
J. J. Clague ◽  
J. E. Armstrong ◽  
W. H. Mathews
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Major Advance ◽  
Radiocarbon Dates ◽  
Coast Mountains ◽  
Growth History ◽  
Glacier Ice ◽  
History Of ◽  
Cordilleran Ice Sheet

AbstractRadiocarbon dates from critical stratigraphic localities in southern British Columbia indicate that the growth history of the late Wisconsin Cordilleran Ice Sheet was different from that of most of the Laurentide Ice Sheet to the east. Much of southern British Columbia remained free of ice until after about 19,000 to 20,000 yr ago; only adjacent to the Coast Mountains is there a record of lowland glacier tongues in the interval 22,000 to 20,000 yr B.P. A major advance to the climax of late Wisconsin Cordilleran glacier ice in the northern States was not begun until after about 18,000 yr B.P. in the southwest of British Columbia and after about 17,500 yr B.P. in the southeast. The rate of glacier growth must have been very rapid in the two to three millennia prior to the climax, which has been dated in western Washington at shortly after 15,000 yr B.P.

Reconstructing the Cordilleran Ice Sheet in northern British Columbia during the Late Pleistocene climate reversals

2020 ◽  
Author(s):  
Helen Dulfer ◽  
Martin Margold
Keyword(s):  
British Columbia ◽  
Late Pleistocene ◽  
Regional Scale ◽  
Ice Sheet ◽  
Younger Dryas ◽  
Western Canada ◽  
Alpine Glaciers ◽  
Pleistocene Climate ◽  
Cordilleran Ice Sheet ◽  
Exposure Ages

<p>The Cordilleran Ice Sheet (CIS) repeatedly covered western Canada during the Pleistocene and attained a volume and area similar to that of the present-day Greenland Ice Sheet. Deglaciation of the CIS following the Last Glacial Maximum (LGM) directly affected atmosphere and ocean circulation, eustatic sea level, and human migration from Asia to North America. It has recently been shown that the rapid climate oscillations at the end of the Pleistocene had a dramatic effect on the CIS. Data on glacial isostatic adjustment and cosmogenic nuclide exposure ages indicate that abrupt warming at the onset of the Bølling-Allerød caused significant thinning of the ice sheet, resulting in a fifty percent reduction in mass, while the Younger Dryas cooling caused the expansion of alpine glaciers across the mountains of western Canada. However, the mountainous subglacial terrain makes it challenging to reconstruct the regional-scale deglaciation dynamics of the ice sheet, and its configuration during this period of rapid change remains poorly constrained. </p><p>Here we use the glacial landform record to reconstruct the ice sheet configuration for the central sector of the CIS, over the Cassiar and Omineca Mountains in northern British Columbia, during the Late Pleistocene climate reversals. We present the first regional-scale reconstruction of the CIS following the Bølling-Allerød warming, whereby the ice sheet was reduced to a labyrinth of valley glaciers fed by ice dispersal centres located over the Skeena Mountains in the south and Coast Mountains in the west. Additionally, numerous lateral and terminal late glacial moraines delineate the extent of alpine glaciers, ice caps and ice fields that regrew on mountain peaks above the CIS during the Younger Dryas. Cross-cutting relationships indicate that the valley glaciers of the CIS were slower to respond to the Younger Dryas cooling than the mountain glaciers.</p>

Multiple Glaciation in Central British Columbia

1971 ◽  
Vol 8 (7) ◽  
pp. 743-752 ◽  
Author(s):  
Howard W. Tipper
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Ice Sheet ◽  
Glacial History ◽  
Ample Evidence ◽  
Coast Mountains ◽  
Lacustrine Deposits ◽  
Glacier Ice ◽  
History Of

During Fraser Glaciation central British Columbia was covered by glacier ice that accumulated in the Coast and Cariboo Mountains, flowed inwardly as a piedmont glacier to the Interior Plateau and thence northeasterly as an ice sheet toward the Rocky Mountains. After withdrawal of the Fraser ice sheet a limited re-advance of ice from Cariboo and Coast Mountains took place but not as a coalescent ice sheet. Drumlinoid forms, eskers, meltwater channels, kettled deposits, and lacustrine deposits provide ample evidence from which a glacial history of the area can be deduced. Although Fraser Glaciation is not believed to have culminated as an ice dome over central British Columbia, there is some evidence to suggest that earlier glaciations did form such a dome from which ice flowed radially over the Coast and Rocky Mountains.

Ice-free conditions in southwestern British Columbia at 16000 years BP

1988 ◽  
Vol 25 (6) ◽  
pp. 938-941 ◽  
Author(s):  
John J. Clague ◽  
Ian R. Saunders ◽  
Michael C. Roberts
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Radiocarbon Dates ◽  
Maximum Extent ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

New radiocarbon dates on wood from two exposures in Chilliwack valley, southwestern British Columbia, indicate that this area was ice free and locally forested 16 000 radiocarbon years ago. This suggests that the Late Wisconsinan Cordilleran Ice Sheet reached its maximum extent in this region after 16 000 years BP. The Chilliwack valley dates are the youngest in British Columbia that bear on the growth of the Cordilleran Ice Sheet.

III.—Recent Observations on the Glaciation of British Columbia and Adjacent Regions

1888 ◽  
Vol 5 (8) ◽  
pp. 347-350 ◽  
Author(s):  
Geo. M. Dawson
Keyword(s):  
British Columbia ◽  
Glacial Period ◽  
Coast Range ◽  
Coast Mountains ◽  
One Stage ◽  
Queen Charlotte Islands ◽  
Glacier Ice ◽  
Inland Ice ◽  
Great Valley ◽  
The U.S

Previous observations in British Columbia have shown that at one stage in the Glacial period—that of maximum glaciation—a great confluent ice-mass has occupied the region which may be named the Interior Plateau, between the Coast Mountains and Gold and Eocky Mountain Kanges. From the 55th to the 49th parallel this great glacier has left traces of its general southward or southeastward movement, which are distinct from those of subsequent local glaciers. The southern extensions or terminations of this confluent glacier, in Washington and Idaho Territories, have quite recently been examined by Mr. Bailley Willis and Prof. T. C. Chamberlin, of the U.S. Geological Survey. There is, further, evidence to show that this inland-ice flowed also, by transverse valleys and gaps, across the Coast Range, and that the fiords of the coast were thus deeply filled with glacier-ice which, supplemented by that originating on the Coast Range itself, buried the entire great valley which separates Vancouver Island from the mainland and discharged seaward round both ends of the island. Further north, the glacier extending from the mainland coast touched the northern shores of the Queen Charlotte Islands.

scholarly journals Englacial lake dynamics within a Pleistocene cordilleran ice sheet at Kima' Kho tuya (British Columbia, Canada)

2021 ◽  
Vol 273 ◽  
pp. 107247
Author(s):  
James K. Russell ◽  
Benjamin R. Edwards ◽  
Marie Turnbull ◽  
Lucy A. Porritt
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Cordilleran Ice Sheet ◽  
Lake Dynamics
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