rock glacier
rock glacier
Tonguelike body of coarse rock fragments, found above the timberline on mountains, that moves slowly down a valley. The rock material usually has fallen from the valley walls and may contain large boulders; it resembles the material left at the end (terminus) of a true glacier. A rock glacier may be 100 ft (30 m) deep and nearly a mile (1.5 km) long.
This entry comes from Encyclopædia Britannica Concise.
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