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Unformatted text preview: Chapter 14 Glacial and Periglacial Landscapes Glaciers About 77% of all freshwater is in glaciers Present rate of melting exceeds all records Past 50 years, 75% of glaciers in European Alps have receded More than 50% of ice mass lost since 1850 Within this century, glaciers in equatorial regions (e.g. Mt. Kilimanjaro) could disappear Melting occurring more rapidly at high latitudes, especially Arctic Occur in high latitudes & high altitudes Large mass of ice that exists year-round Can rest on land or float on sea adjacent to land (ice shelf) Today, 11% of Earths land area In past, 30% Continual accumulation of snow recystallizes into ice mass Form in areas of permanent snow Snowline lowest elevation with year-round snow Snow accumulates in a snowfield (higher elevation or latitude) and compacts under weight Takes many years to become glacial ice After first summer, recrystallization and compaction firn Firn has compact, granular texture Over many years, compacts to a dense ice Snow firn glacial ice In Antarctica, may take 1000 years (cold & dry, lacks precipitation) Rivers of Ice Move under pressure, under pull of gravity, like a river rivers of ice Glaciers Two types continental and alpine Alpine glacier = mountain glacier Continental glacier larger than alpine Ice sheet is largest form Cover 80% of Greenland and 90% of Antarctica 91% of all glacial ice on planet is in Antarctica...
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This note was uploaded on 04/20/2008 for the course GEOS 200 taught by Professor Hanchette during the Spring '08 term at University of Louisville.
- Spring '08