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This serves as an alternative to the Ice Free Corridor previously posited to have allowed for migration amid the retreat of the eastern front of the Cordilleran ice sheet and the western front of the Laurentide ice sheet. [11] The Ice Free Corridor is a subject of debate among anthropologists in recent years.
The Cordilleran ice sheet dammed up Glacial Lake Missoula at the Purcell Trench Lobe. [10] A series of floods occurring over the period of 18,000 to 13,000 years ago swept over the landscape when the ice dam broke. The eroded channels also show an anastomosing, or braided, appearance.
Running water has etched out the grain of the range, landslides have softened the abrupt edges, homegrown glaciers have scoured the peaks and high valleys and, during the Ice Age, the Cordilleran Ice Sheet overrode almost all the range and rearranged courses of streams. Erosion has written and still writes its own history in the mountains, but ...
Mount Edziza, a stratovolcano in northwestern British Columbia A topographic map of Canada, showing elevations shaded from green (lower) to brown (higher). Volcanic activity is a major part of the geology of Canada and is characterized by many types of volcanic landform, including lava flows, volcanic plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes ...
The first volcano-ice interaction is displayed as tuyas, including Tuya Butte, on the Tanzilla Plateau in the Northern Interior of British Columbia. [18] This sub-section of the Stikine Plateau consists of large flatlands with hills of low relief, and might have been one of the areas of ice accumulation for the Cordilleran Ice Sheet. [18]
The Cordilleran ice sheet also blocked the Clark Fork River and created Glacial Lake Missoula, rising behind a 2,000 feet (610 m) high ice dam in flooded valleys of western Montana. Over 2000 years the ice dam periodically failed, releasing approximately 40 high-volume Missoula Floods of water down the Columbia River drainage, passing through ...
The Cordilleran mountains were formed by the collision of the Pacific and North American tectonic plates causing the crust to buckle, creating the mountain ranges that are known today. This is the youngest of the three primary geographic regions of Canada, the others being the Canadian Shield and Interior Plains.
The Skagit River was highly influenced by the repeated advance and retreat of the Puget Lobe of the Cordilleran Ice Sheet. Ice and gravel moraines repeatedly blocked the Skagit, causing it to pool into lakes and forcing it to drain south into the future North Fork Stillaguamish River. After the ice retreated the Skagit breached the moraine dam ...