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TitleA new glacial isostatic adjustment model of the Innuitian Ice Sheet, Arctic Canada
AuthorSimon, K M; James, T S; Dyke, A S
SourceQuaternary Science Reviews vol. 119, 2015 p. 11-21,
Alt SeriesEarth Sciences Sector, Contribution Series 20140325
Mediapaper; digital; on-line
File formatpdf
ProvinceNunavut; Northwest Territories
NTS38; 39; 48; 49; 58; 59; 68; 69; 78; 79; 88; 89; 98; 120; 340; 560
AreaInnuitian Ice Sheet; Arctic Canada
Lat/Long WENS-122.0000 -74.0000 80.0000 74.0000
Subjectssurficial geology/geomorphology; isostasy; isostatic rebound; glacial history; models; modelling; Innuitian Ice Sheet; global positioning system; Cenozoic; Quaternary
Illustrationslocation maps; plots; images
ProgramCoastal Infrastructure, Climate Change Geoscience
AbstractA reconstruction of the Innuitian Ice Sheet is developed that incorporates first-order constraints on its spatial extent and history as suggested by regional glacial geology studies. Glacial isostatic adjustment modelling of this ice sheet provides relative sea-level predictions that are in good agreement with measurements of post-glacial sea-level change at 18 locations. The results indicate peak thicknesses of the Innuitian Ice Sheet of approximately 1600 m, up to 400 m thicker than the minimum peak thicknesses estimated from glacial geology studies, but between approximately 1000 to 1500 m thinner than the peak thicknesses present in previous GIA models. The thickness history of the best-fit Innuitian Ice Sheet model developed here, termed SJD14, differs from the ICE-5G reconstruction and provides an improved fit to sea-level measurements from the lowland sector of the ice sheet. Both models provide a similar fit to relative sea-level measurements from the alpine sector. The vertical crustal motion predictions of the best-fit IIS model are in general agreement with limited GPS observations, after correction for a significant elastic crustal response to present-day ice mass change. The new model provides approximately 2.7 m equivalent contribution to global sea-level rise, an increase of +0.6 m compared to the Innuitian portion of ICE-5G.
Summary(Plain Language Summary, not published)
This paper describes development of a computer model to better explain measured sea-level change in the Canadian High Arctic over the past 8000 years. The computer model consists of a description of the thickness history and spatial extent of the ice sheet that was present in the area (the Innuitian Ice Sheet) and a model of how the Earth responds to changes in surface loading brought about by the growth and decay of the ice sheet. The new model provides improved agreement with sea-level histories from 18 localities in the High Arctic and revises the estimate of how much water the decay of the Innuitian Ice Sheet delivered to the world's oceans during deglaciation to 2.7 m, an increase 0.6 m from the starting model. The new model also provides improved agreement with measured vertical land motion from 3 GPS sites in the region. Models that describe vertical land motion and sea-level change at specific locations are useful for understanding changes across large regions of Canada.