Skip to Main Content
Book Chapter

Multiple Younger Dryas and Allerød moraines (Sumas Stade) and late Pleistocene Everson glaciomarine drift in the Fraser Lowland

By
Don J. Easterbrook
Don J. Easterbrook
Department of Geology, Western Washington University, Bellingham, Washington 98225, USA
Search for other works by this author on:
Published:
January 01, 2014

Abstract

As the late Pleistocene Cordilleran Ice Sheet (CIS) retreated from the southern Puget Lowland and thinned rapidly, marine waters invaded the central and northern lowland, floating the residual ice and causing wholesale collapse of the CIS from southern Whidbey Island to southern British Columbia. Massive, poorly sorted Everson glaciomarine drift was deposited contemporaneously over the entire central and northern lowland. More than 160 14C dates show that the Everson interval began 12,500 14C yr B.P. and ended 11,700 14C yr B.P. Numerous marine strandlines record the drop in relative sea level in the Fraser Lowland from ~180 m (600 ft) at the end of the Everson interval to near present sea level.

Following emergence of the Fraser Lowland, a lobe of the CIS advanced from the Fraser Canyon near Sumas to Bellingham during the Sumas Stade. As the ice retreated, at least eight end moraines were built successively across the lowland, each marking a position of ice advance or stillstand that records late Pleistocene climatic fluctuations. About 40 new 14C dates indicate that the ages of these moraines span the Inter-Allerød–Younger Dryas intervals between 11,700 and 10,000 14C yr B.P. The 14C chronology allows correlation of the Sumas moraines with moraines in the Cascade Range, Rocky Mountains, Canada, Scandinavia, the European Alps, New Zealand, South America, and elsewhere. Late in the retreat of the ice, large outburst floods from an ice-dammed lake in British Columbia swept across the Sumas outwash plain, resulting in fluted topography and giant ripples on dune forms.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables

Contents

GSA Field Guide

Trials and Tribulations of Life on an Active Subduction Zone: Field Trips in and around Vancouver, Canada

Shahin Dashtgard
Shahin Dashtgard
Department of Earth Sciences Simon Fraser University 8888 University Drive Burnaby, British Columbia V5A 1S6, Canada
Search for other works by this author on:
Brent Ward
Brent Ward
Department of Earth Sciences Simon Fraser University 8888 University Drive Burnaby, British Columbia V5A 1S6, Canada
Search for other works by this author on:
Geological Society of America
Volume
38
ISBN electronic:
9780813756387
Publication date:
January 01, 2014

References

Related

A comprehensive resource of eBooks for researchers in the Earth Sciences

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal