A bowl-shaped, amphitheater-like depression eroded into the head or the side of a glacier valley. Typically, a cirque has a lip at its lower end. The term is French and is derived from the Latin word circus.

Any curved mark or fracture produced by plucking or chipping of the glacier's bed. Larger than chatter marks,typically the horns of these gouges point up glacier. Also called Lunate Fracture or Crescentic Mark.

A series of small, closely spaced, crescentic grooves or scars formed in bedrock by rocks frozen in basal ice as they move along and chip the glacier's bed. The horns of the crescent generally point down glacier.

U.S. Department of the Interior | U.S. Geological Survey URL: http://pubsdata.usgs.gov/pubs/of/2004/1216/c/c.html Page Contact Information: GS Pubs Web Contact Page Last Modified: Saturday, 12-Jan-2013 23:18:37 EST

A crack or series of cracks that open in the surface of a moving glacier in response to differential stresses caused by glacier flow. They range in shape from linear to arcuate, in length from feet to miles. Their orientation may be in any direction with respect to the glacier flow. The deepest crevasses may exceed 100 feet.

The process by which pieces of ice break away from the terminus of a glacier that ends in a body of water or from the edge of a floating ice shelf that ends in the ocean. Once they enter the water, the pieces are called icebergs.