CGRG Bibliography of Canadian Geomorphology
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Author : Donnelly, J.P.
Date : 1999
Title : Geographic variability in Late Holocene Eastern North American sea level trends.
Publication : Program and Abstracts, American Geophysical Union, Spring Meeting, Boston, Massachussetts, June 1 - 4, 1999.
Issue :
Page(s) :
Abstract
Changes in relative sea level recorded in salt marsh deposits integrate the many different components of sea level variations at a variety of spatial and temporal scales. In previously glaciated regions the signal at the millennium scale is often dominated by vertical crustal movements associated with post-glacial isostatic adjustment. The best data on late Holocene sea levels in the eastern North America is obtained by the radiocarbon dating of basal salt marsh sediments. Ideal samples are contain evidence of formation at or near mean high water (MHW), such as vegetation endemic to the high salt marsh or the presence of other proxies such as microfaunal assemblages. In order to examine regional trends in sea level, this study provides data from several new sites augmenting a compilation of previously published data. The vertical range of sea level indicators has been estimated based on published descriptions of sample material and in certain cases local tidal range. A continuum of differential crustal subsidence is evident in eastern North America for the latter half of the Holocene. A maximum zone of subsidence exists in New Brunswick and Nova Scotia. Regions of little or no vertical crustal movement exist from approximately Boston, MA northeast along the Maine coast, Bermuda and in the southeastern United States, while an intermediate zone of subsidence exists in southern New England, Long Island and New Jersey. This pattern consistent with the migration of a peripheral forebulge, in the direction of the origin of Laurentide Ice Sheet in central Canada.
Bibliography of Canadian Geomorphology