GEO 120 Lecture Notes - Lecture 11: Mass Wasting, Terminal Moraine, Landform
21 Oct 2016
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Geo 123 - lecture 11 - glaciers - elizabeth laliberte. Masses of ice that moves over land by the pressure of their own weight. Form where more snow falls in winter than melts in summer. Snow accumulates and is eventually compacted into ice. Cover all but the highest parts of the underlying ground. Accounting the gain or loss of snow that occur over a time period. Addition of snow and ice by snowfall or frost. Removal of glacial ice or snow by melting, sublimation, calving, evaporation. If accumulations > ablation, the glacier gets bigger. If ablation > accumulations, the glacier gets smaller. More ablation, glacier getting smaller, will retreat. Normal flow for glacial ice 10 to 300 m per year. Surges (faster flow) 20 to 110 m per day. Plucking: rocks become frozen in meltwater and are removed as the glacier advances. Abrasion: scraping by the rocks and material from the weight of the glacier.
