Post-glacial uplift and substrate age at Cape Henrietta Maria, southeastern Hudson Bay, Canada

Abstract

As a basis for future ecological and biogeographical studies, the post-glacial emergence history of Cape Henrietta Maria was required. This was obtained by fitting a post-glacial emergence curve to a number of radiocarbon dated marine strandlines of known elevation. Analysis shows that the elevation of lower samples is critical for a reasonable prediction of higher relative sea levels. This emergence curve suggests that during the last 1000 y uplift has been about 1.2 m per century. Extrapolation to likely dates of deglaciation (8000−7000 BP) indicates a maximum marine inundation of > 300 m. The current rate of uplift, and the hypothetical elevation of the marine limit are the highest estimations to date for eastern and arctic Canada and support the hypothesis that a center of uplift and ice-loading is situated in southeastern Hudson Bay and northern James Bay. The derived emergence curve was used to construct an isochrone map of Polar Bear Park, in eastern northern Ontario. This map provides the basis for future biological studies of community migration and succession and demonstrates that the uplift curve is a useful chronological tool.