GEOB 103 Study Guide - Aretes, Silt, Proglacial Lake
Document Summary
A glacier is a mass of ice that has its genesis on land and that represents a multiyear surplus of snowfall over snowmelt. Glacial ice accumulates in mountains (alpine glaciers) or over continents (ice sheets, ice caps). Glaciers are found in mountainous areas throughout the world, from the tropics to the poles. Perennial ice covers about 11% of the land areas of the earth. 2 million years, glaciers and ice sheets expanded to cover about 29% of the total land area of the earth. Glaciers form in any area in which annual snow accumulation > snow melt. Successive layers of snow are slowly compacted until the loose snowflakes gradually become more and more dense with increasing depth and age. As gravity slowly deforms this mass of ice and it begins to flow, a glacier is formed. Fluctuations of the volume of glacier ice are related to climatic variations in temperature and precipitation.
