Retreat pattern of the Cordilleran Ice Sheet in central British Columbia at the end of the last glaciation reconstructed from glacial meltwater landforms
The C ordilleran I ce S heet ( CIS ) covered much of the mountainous northwestern part of N orth A merica at least several times during the P leistocene. The pattern and timing of its growth and decay are, however, poorly understood. Here, we present a reconstruction of the pattern of ice‐sheet retr...
| Published in: | Boreas |
|---|---|
| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2013
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/bor.12007 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fbor.12007 https://onlinelibrary.wiley.com/doi/pdf/10.1111/bor.12007 |
| Summary: | The C ordilleran I ce S heet ( CIS ) covered much of the mountainous northwestern part of N orth A merica at least several times during the P leistocene. The pattern and timing of its growth and decay are, however, poorly understood. Here, we present a reconstruction of the pattern of ice‐sheet retreat in central B ritish C olumbia at the end of the last glaciation 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 (1600–2400 m a.s.l.), ice‐marginal meltwater channels is evident across central B ritish C olumbia. These landforms indicate the presence of ice domes over the S keena M ountains and the central C oast M ountains early during deglaciation. Ice sourced in the C oast M ountains remained dominant over the southern and east‐central parts of the I nterior P lateau during deglaciation. Our reconstruction shows a successive westward retreat of the ice margin from the western foot of the R ocky M ountains, accompanied by the formation and rapid evolution of a glacial lake in the upper F raser R iver basin. The final stage of deglaciation is characterized by the frontal retreat of ice lobes through the valleys of the S keena and O mineca M ountains and by the formation of large esker systems in the most prominent topographic lows of the I nterior P lateau. We conclude that the CIS underwent a large‐scale reconfiguration early during deglaciation and was subsequently diminished by thinning and complex frontal retreat towards the C oast M ountains. |
|---|