Science / Geology / Glacier: A thick mass of ice that forms on land from an accumulation and recrystallization of snow significant enough to persist through the summer and grow year by year. There are two basic types of glaciers: 1) valley (or alpine) glaciers that creep downslope under the influence of gravity, and 2) continental glaciers that flow outward from a thick central area under their own weight.
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Science / Geology / Valley Glacier: A glacier that is smaller than a continental glacier or an icecap, and which flows mainly along well-defined valleys, many with tributaries. MORE
Science / Geology / Rock Glacier: A mass of rock material, cemented together by ice, that flows down a slope under the force of gravity much like the motion of a glacier. MORE