Late-glacial retreat pattern of the Cordilleran Ice Sheet in central British Columbia reconstructed from glacial meltwater landforms
(English)Article in journal (Refereed) Submitted
The Cordilleran Ice Sheet (CIS) covered much of the mountainous northwestern part of North America during Pleistocene glaciations. In contrast to other ephemeral Pleistocene ice sheets, the pattern and timing of growth and decay of the CIS are poorly understood. Here, we present a reconstruction of the pattern of late-glacial ice sheet retreat in central British Columbia based on a palaeoglaciological interpretation of ice-marginal meltwater channels, eskers, and deltas mapped from satellite imagery and digital elevation models. A consistent spatial pattern of high-elevation ice-marginal meltwater channels (1600-2400 m a.s.l.) occurs across central British Columbia. They indicate the presence of ice domes over the Skeena Mountains and the central Coast Mountains early during deglaciation. Ice sourced in the Coast Mountains remained dominant over the southern and east-central parts of the Interior Plateau during late-glacial time. Our reconstruction shows a successive westward retreat of the ice margin away from the western foot of the Rocky Mountains, accompanied by the formation and rapid evolution of a glacial lake in the upper Fraser River basin. Final stages of deglaciation were characterized by the frontal retreat of ice lobes through the valleys of the Skeena and Omineca mountains and by the formation of large esker systems in the most prominent topographic lows of the Interior Plateau. We conclude that the CIS underwent a large-scale reconfiguration early during deglaciation and subsequently diminished by thinning and complex frontal retreat towards the Coast Mountains.
Cordilleran Ice Sheet, ice retreat pattern, deglaciation, glacial meltwater landforms
Physical Geography Geology Climate Research Geosciences, Multidisciplinary
Research subject Quarternary Geology; Physical Geography
IdentifiersURN: urn:nbn:se:su:diva-68954OAI: oai:DiVA.org:su-68954DiVA: diva2:474257