CGRG Bibliography of Canadian Geomorphology
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Author : Braun, A.; Shum, C.K.; Potts, L.V.; Kuo, C.-Y.; and Trupin, A.
Date : 2003.
Title : Glacial isostatic adjustment in the Great Lakes region.
Publication : European Geophysical Society (EGS) - American Geophysical Union (AGU) European Union of Geosciences (EUG) Joint Assembly. Nice, France, 06 - 11 April 2003. Geophysical Research Abstracts
Issue : 5:
Page(s) : 07779.
Abstract
The deglaciation cycles of the Laurentide ice sheets have dominated the Glacial Isostatic Adjustment (GIA) in the Great Lakes region. However, beside the GIA induced deformation, tectonic processes and mantle flow have a significant contribution to the lithosphere’s deformation. A separation of the two signals is necessary before using deformation data to constrain Earth parameters, like viscosity, or ice loading history. The Great Lakes region is covered by a suite of different geodetic sensors allowing to quantify the vertical motion at particular sites. A combination of GPS, absolute gravity, satellite altimetry and water-level gauges provide independent means to measure present-day crustal motion. Results obtained from this technique have been validated by comparison with vertical motions from the BIFROST project in Fennoscandia. The vertical motion of the Great Lakes region shows uplift in the Northern part, while the Southern part is subsiding. Since the maximum Southern extend of the Laurentide ice sheet was located in that area, analyzing the present-day deformation can deliver valuable constraints on Earth parameters. The visco-elastic response at the former ice margin shows a significantly different sensitivity to viscosity compared to the former center of the ice sheet or the far field. Here, the visco-elastic response is especially sensitive to the uppermost mantle viscosity. Vertical motion in the Great Lakes region from multiple observations (GPS, GIA models, altimetry-water level gauges) is presented together with initial results of the separation of tectonic and GIA induced signals. A multi-resolution analysis of gravity data using wavelets has been employed to find spatial and spectral characteristics. GIA modeling using vertical motion observations has been carried out in order to get improved constraints of GIA parameters.
Bibliography of Canadian Geomorphology