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TitleA relative sea-level history for Arviat, Nunavut, and implications for Laurentide Ice Sheet thickness west of Hudson Bay
AuthorSimon, K M; James, T S; Forbes, D L; Telka, A M; Dyke, A S; Henton, J A
SourceQuaternary Research (New York) vol. 82, issue 1, 2014 p. 185-197,
Alt SeriesEarth Sciences Sector, Contribution Series 20140009
Mediapaper; on-line; digital
File formatpdf
NTS55E; 55E; 55L/01; 55L/02; 55L/03; 55L/04; 65H/09; 65H/10; 65H/15; 65H/06; 65I/01; 65I/02
AreaKaminak Lake; Maguse Lake; Yandle Lake; Arviat; Kivalliq
Lat/Long WENS-97.0000 -93.5000 62.3333 60.5000
Subjectsgeochronology; radiocarbon dating; isostasy; isostatic rebound; sea level fluctuations; sea level changes; Holocene; crustal uplift; modelling; ice sheets; Laurentide Ice Sheet; Tyrrell Sea; Quaternary
Illustrationsphotographs; location sketch maps; analyses
ProgramCoastal Infrastructure, Climate Change Geoscience
AbstractThirty-six new and previously published radiocarbon dates constrain the relative sea-level history of Arviat on the west coast of Hudson Bay. As a result of glacial isostatic adjustment (GIA) following deglaciation, sea level fell rapidly from a high-stand of nearly 170 m elevation just after 8000 cal yr BP to 60 m elevation by the mid Holocene (~ 5200 cal yr BP). The rate of sea-level fall decreased in the mid and late Holocene, with sea level falling 30 m since 3000 cal yr BP. Several late Holocene sea-level measurements are interpreted to originate from the upper end of the tidal range and place tight constraints on sea level. A preliminary measurement of present-day vertical land motion obtained by repeat Global Positioning System (GPS) occupations indicates ongoing crustal uplift at Arviat of 9.3 ± 1.5 mm/yr, in close agreement with the crustal uplift rate inferred from the inferred sea-level curve. Predictions of numerical GIA models indicate that the new sea-level curve is best fit by a Laurentide Ice Sheet reconstruction with a last glacial maximum peak thickness of ~ 3.4 km. This is a 30--35% thickness reduction of the ICE-5G ice-sheet history west of Hudson Bay.
Summary(Plain Language Summary, not published)
We carried out field work west of Hudson Bay, in the vicinity of the community of Arviat, Nunavut. The field work focused on the collection of samples related to past sea levels, such as marine shells and driftwood located inland from the present-day shoreline. We radiocarbon-dated several of these samples, and were then able to construct a record of regional sea level change for the last several thousand years. This sea level history shows that sea level has been continuously falling as the result of ongoing land uplift after the retreat of the Laurentide ice sheet (a process known as postglacial rebound). The sea level history also allows us to estimate the rate of present-day vertical land uplift, and we find that our estimated rate of around 9.2 mm/yr is in good agreement with a preliminary rate measured by an installed GPS site. By comparing the observed sea level history to numerical model predictions, we are able to show that current model reconstructions of the Laurentide ice sheet likely feature ice that is ~30% too thick west of Hudson Bay.