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TitleContrasting glacial sedimentation processes and sea-level changes in two adjacent basins on the Pacific margin of Canada
AuthorBarrie, J V; Conway, K W
SourceGlacier-influenced sedimentation on high-latitude continental margins; by Dowdeswell, J A (ed.); Ó Cofaigh, C (ed.); Geological Society, Special Publication vol. 203, 2002 p. 181-194, https://doi.org/10.1144/gsl.sp.2002.203.01.10
Year2002
Alt SeriesGeological Survey of Canada, Contribution Series 2001037
PublisherGeological Society of London
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceBritish Columbia; Western offshore region
NTS82E/03; 82E/04; 82E/05; 82E/06; 82E/11; 82E/12; 82E/13; 82E/14; 82F/03; 82F/04; 82F/05; 82F/06; 82F/11; 82F/12; 82F/13; 82F/14; 82M/03; 82M/04; 82M/05; 82M/06; 82M/11; 82M/12; 82M/13; 82M/14; 92; 93E/03; 93E/04; 93E/05; 93E/06; 93E/11; 93E/12; 93E/13; 93E/14; 93F/03; 93F/04; 93F/05; 93F/06; 93F/11; 93F/12; 93F/13; 93F/14; 93M/03; 93M/04; 93M/05; 93M/06; 93M/11; 93M/12; 93M/13; 93M/14; 102; 103A; 103B; 103C; 103F; 103G; 103H; 103I; 103J; 103K
AreaVancouver Island; Victoria; Campbell River; Comox; Texada Island; Hornby Island; Strait of Juan de Fuca; Strait of Georgia; Fraser Delta; Fraser River; Washington State; Puget Sound; Queen Charlotte Islands; Graham Island; Moresby Island; Masset Inlet; Dixon Entrance; Hecate Strait; Queen Charlotte Sound; Prince Rupert; Kitimat; Queen Charlotte Basin; Pacific Ocean; Queen Charlotte Basin; Georgia Basin; Haida Gwaii; Canada; United States of America
Lat/Long WENS-134.0000 -119.0000 55.0000 46.5000
Subjectssurficial geology/geomorphology; stratigraphy; geochronology; glacial deposits; glacial history; glacial landforms; glaciation; ice movement; sea level changes; deglaciation; stratigraphic analyses; Wisconsin Fraser Glaciation; Pacific Margin; Cenozoic; Quaternary
Illustrationslocation maps; geological sketch maps; profiles; stratigraphic sections; tables; graphs
ProgramGeorgia Basin Geohazards Initiative
Released2002 01 01
AbstractDuring the late Wisconsin Fraser Glaciation on the Pacific Margin of Canada, ice moved offshore from the Coast Mountains of the Canadian Cordillera and south into the Strait of Georgia, reaching a maximum extent at about 14 000 14C bp. Most of the strait was ice-free by 11 300 14C bp. Deglaciation was very rapid with regional downwasting and widespread stagnation. This resulted in a stratigraphy of thick till (30-60 m), overlain by ice-proximal glacimarine sediments and a thin and discontinuous ice-distal glacimarine unit. Glaciation of Queen Charlotte Basin reached a maximum sometime after 21 000 14C bp. Deglaciation in this region began sometime after 16 000 to 15 000 14C bp and ice had retreated fully onto mainland British Columbia by 13 500 14C bp. Deglaciation was rapid, with the eastward retreat of an ice shelf. This resulted in a stratigraphy of a till up to 50 m in thickness, usually turbated by iceberg scour and overlain in some areas by thin, ice-proximal glacimarine sediments and much thicker (20 m) widespread ice-distal glacimarine sediments. A significant difference between these two regions is the deglacial relative sea-level history. Rapid regression of the outer Queen Charlotte Islands shelf occurred between approximately 14 600 and 12 500 14C bp, primarily due to rapid isostatic rebound and contemporaneous with deglaciation of the continental shelf. Sea-level reached a maximum lowstand of greater than 150 m and remained low until approximately 12 400 14C bp. In Georgia Basin, sea-level was at a relative high stand of 50 to 200 m during initial deglaciation, falling to between 0 to 50 m below present sometime after 10 000 14C bp. We suggest that rapid emergence on the northern margin of the outer shelf was due to forebulge effects. Further, the very limited extent of glacial ice on the Queen Charlotte Islands and the exposure to the open Pacific forced the retreat of the Cordilleran ice-sheet margin eastwards thereby resulting in dominantly ice-distal glacimarine sedimentation. In contrast, the initial relative sea-level highstand during deglaciation between the Vancouver Island and Cordilleran glaciers in the Strait of Georgia resulted in significant ice-proximal deposition and limited ice-distal glacimarine deposition.
GEOSCAN ID212296