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TitleForms, response times and variability of relative sea-level curves, glaciated North America
AuthorDyke, A S; Peltier, W R
SourceGeomorphology vol. 32, 2000 p. 315-333,
Alt SeriesGeological Survey of Canada, Contribution Series 1998078
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf
ProvinceSaskatchewan; Northwest Territories; Nunavut; Manitoba; New Brunswick; Prince Edward Island; Ontario; Quebec; Nova Scotia; British Columbia; Yukon; Newfoundland and Labrador
NTS1; 2; 3; 10; 11; 12; 13; 14; 20; 21; 22; 23; 24; 25; 26; 27; 31; 32; 33; 34; 35; 36; 37; 38; 39; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 74; 75; 76; 77; 78; 79; 86; 87; 88; 89; 120; 340; 560; 82; 92; 93; 94; 95; 103; 104; 105; 106; 107; 114; 115; 116; 117
AreaCanada; United States of America
Lat/Long WENS-168.0000 -50.0000 90.0000 14.0000
Subjectssurficial geology/geomorphology; geochronology; sedimentology; sea level changes; sea level fluctuations; isostasy; ice sheets; Holocene; emergence; submergence; radiocarbon dates; Pleistocene; Laurentide Ice Sheet; Innuitian Ice Sheet; Fennoscandia Ice Sheet; Quaternary
Illustrationssketch maps; analyses
AbstractRelative sea level curves from glaciated North America reveal coherent spatial patterns of response times. In the Laurentide Ice Sheet area, curve half-lives range from 1.2-1.4 ka at the uplift centre to 1.7-2 ka in a ridge of high values inboard of the glacial limit. Half-lives decline from this ridge to less than 1 ka along the margin. In the Innuitian Ice Sheet area, half-lives are about 2 ka at the uplift centre and decline to less than 1 ka at the margin. The central Laurentide response times are about half those of central Fennoscandia. This accords with the theoretical expectation that central response times are inversely proportional to ice sheet radius for ice loads large enough that rebound at the centre is insensitive to lithospheric thickness. The Innuitian central response time indicates that rebound at the centre of this ice sheet, which is much smaller than the Fennoscandian Ice Sheet, remains sensitive to lithospheric thickness. Radial gradients in response times reflect the increasing influence of the lithosphere at sites increasingly closer to the margin. Along this gradient, rebound progresses as though at the centres of smaller and smaller ice sheets. That is, the effective spatial scale of the ice load decreases toward the margin. Near the glacial limit, postglacial isostatic adjustment is complicated by forebulge migration and collapse. This is seen most strongly in the relative sea level record of Atlantic Canada, which has subsided during the Holocene more than 20 m more than the adjacent American seaboard. The relative sea level history of some areas, notably the St. Lawrence Estuary, is complicated by tectonic processes.