GEOL 001 Lecture 19: Geol 001 - LEC19
20 Dec 2020
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Document Summary
Valley (alpine) glaciers: exist in mountainous areas, flow down a valley from an accumulation center at its head. Slightly more than 2% of the world"s water is tied up in glaciers. Antarctic ice sheet: 80% of the world"s ice, nearly 2/3rds of earth"s fresh water, covers almost 1 and times the area of the us, if melted, sea level would rise 60-70 meters. Glaciers form in areas where more snow falls in winter than melts during the summer. Steps in the formation of glacial ice. Snowflakes become smaller, thicker, and more spherical. Snow is recrystallized into a much denser mass of small grains called firn. Once the thickness of ice and snow exceeds 50 meters, firn fuses into a solid mass of interlocking ice crystals. Movement is referred to as flow: 2 basic types, plastic flow. Under pressure, ice behaves as a plastic material. Occurs because of molecular structure of ice.
