Late Holocene sea-level changes and isostatic crustal movements in Atlantic Canada

摘要

It has long been recognised that sea levels along the shores of Atlantic Canada have been rising rapidly during the Holocene in response to isostatic crustal movements. New sea-level data for the Bay of Fundy coast of southern New Brunswick (Little Dipper Harbour) and the Atlantic coast of Nova Scotia (Chezzetcook Inlet) show that late Holocene average rates of sea-level rise in these areas have been 1.0 and 2.5m per 1000 yr, respectively. Numerical model calculations suggest that the high rates of sea-level rise are due to crustal subsidence produced by the combined effects of Laurentide ice loading (forebulge collapse) and ocean loading of the Scotian shelf. Although ice loading is the dominant contributor to the regional sea-level pattern, ocean loading is also important, contributing up to ～40% of the total crustal subsidence in some areas. Tide gauges record rates of sea-level rise during the 20th century that are 0.7-1.9 mm/yr higher than late Holocene trends, with the highest residuals occurring in the Bay of Fundy.