A Conceptual Model for Growth and Decay of the Cordilleran Ice Sheet

• Published in: Géographie physique et Quaternaire
• Main Author: Fulton, Robert J.
• Format: Text
• Language: English
• Published: Les Presses de l'Université de Montréal 1991
• Subjects: Yukon; Ice cap; Ice Sheet
• Online Access: http://id.erudit.org/iderudit/032875ar; https://doi.org/10.7202/032875ar

A conceptual model for growth and decay of the Cordilleran Ice Sheet has evolved over 100 years of Quaternary research in British Columbia. Physiography and location relative to prevailing westerly winds were the main factors controlling the style of glacier build up. The pattern of decay was controlled mainly by physiography. With cooling at the beginning of glaciation, mountain glaciers expanded to become valley glaciers and eventually coalesced on adjacent plateaus or shelves to form an ice sheet. At glacial maximum, this sheet extended from the western margin of the continental shelf to the eastern edge of the Rocky Mountains and from the Columbia Plateau to the central Yukon. The central (highest) part of the ice sheet was hemmed in by mountains, consequently, snowline had to rise nearly to its present elevation before shrinking of the central core could begin. This meant that mountain glaciers which initiated growth of the ice sheet were reduced to near their present dimensions before significant recession could take place in the core area of the ice sheet. As a consequence, large ice masses in the interior of British Columbia stagnated and then shrank to remnants occupying major valleys and eventually were reduced to dead ice blocks buried in glacial debris. This pattern of retreat contrasts with that of ice masses centred on mountain blocks, such as the Alps, where rising of the snowline resulted in recession of ice cap margins back towards original accumulation areas in the central core of the mountains. La modélisation de l'évolution de l'Inlandsis de la Cordillère a évolué au cours de la centaine d'années de recherches menées en Colombie-Britannique. Si le développement de l'inlandsis a surtout été déterminée par le relief et la localisation par rapport aux vents dominants, le retrait glaciaire a, par contre, principalement été commandé par le relief. Au début de la glaciation, le climat se refroidissant, les glaciers alpins ont progressé pour devenir des glaciers de vallée, qui se sont par la suite ...