Three alternative hypotheses for the timing and rate of deglaciation in the outer fiords and coasts of the eastern Canadian Arctic are tested by a computer program that provides information on the amount and form of crustal deflection according to a two-layer geophysical model. The three alternative hypotheses are (1) a glacial advance that started about 20,000 B.P. and reached a maximum at the outer coast at 18,000 B.P. and a slow glacial retreat that began at 14,000 B.P., (2) a glacial advance about 20,000 B.P. with the glacial margin stabilized along the Cockburn moraines near the fiord heads from 15,000 to 8000 B.P., and (3) a glacial advance to the coast from 20,000 to 19,000 B.P. with the glacial margin stabilized until 9000 B.P. and then a rapid glacial retreat to the fiord heads.

The derived-deflection and relative-sea-level curves, for a position equivalent to the outer coast of Baffin Island, indicate that the results from hypotheses 1 and 3 are incompatible with the observed distribution of raised Holocene and late Pleistocene marine sediments and their associated 14C dates. In contrast, the curve for relative sea level from hypothesis 2 explains significant elements of the distribution of radiocarbon dates and suggests that a marine transgression affected the outer coast until about 8500 B.P. The marine transgression was not caused by the peak in eustatic sea level but by the glacio-isotatic depression of the coast maintained by the stable mass of the northeastern sector of the Laurentide Ice Sheet.

First Page Preview

First page PDF preview
You do not currently have access to this article.