Converging Valley Glaciers

July 27, 2005

P7010074 copy

Provided and copyright by: David W. Martin
Summary authors & editors: Marion O. Weaver

The photo above showing converging valley glaciers was taken from Wrangell–Saint Elias National Park, Alaska in June of 2003. These glaciers have lateral (side) moraines that formed as bedrock was scraped off the valley walls, and carried along the glacier-valley wall interface. As two valley glaciers converge (e.g., river tributaries as an analogy), the adjoining lateral moraines form a medial or middle moraine, which appears as a ribbon of concentrated glacial debris. When glaciers eventually melt, their moraines are left behind -- composition and height depend on the length of time the ice remained at a particular point and on the type of material being eroded.

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