crevasse

crevasse (krəvăsˈ) [key], large crack in the upper surface of a glacier, formed by tension acting upon the brittle ice. Transverse crevasses occur where the grade of the glacier bed becomes suddenly steeper; longitudinal crevasses, where the glacier spreads over a wider valley or plain. Marginal crevasses are due to the strain built up when the central part moves faster than the sides.

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