A record of ice sheet demise

• Published in: Science (American Association for the Advancement of Science) Vol. 358; no. 6364; pp. 721 - 722
• Main Authors: Marcott, Shaun A., Shakun, Jeremy D.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 10-11-2017; The American Association for the Advancement of Science
• Subjects: Alpine environments; Canadian Shield; Chronology; Deglaciation; Glaciation; Glaciers; Ice; Ice ages; Ice Cover; Migration; PERSPECTIVES; Seawater; Topography; Canada
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aaq1179

The Cordilleran ice sheet in western Canada melted sooner than previously thought
The Cordilleran ice sheet once covered nearly all of western Canada, from the Puget Lowland of Washington to the southern reaches of Alaska (
1
). Unlike the Laurentide ice sheet, which covered the relatively flat Canadian shield of eastern Canada, the Cordilleran ice sheet blanketed the high alpine peaks of the Canadian Rockies and Coast Ranges. Although relatively small (
2
), it was nonetheless important for shaping the landscape. It also played a critical role in paleohuman migration from Asia to North America (
3
) and potentially in past rapid climate events (
4
). However, the timing and style of the ice sheet's final demise after the last ice age have been unclear. On page 781 of this issue, Menounos
et al.
(
5
) provide an extensive chronology of Cordilleran ice sheet deglaciation.