Glacial abrasion is commonly characterized by glacial striations. Glaciers produce these when they contain large boulders that carve long scratches in the bedrock. By mapping the direction of the striations, researchers can determine the direction of the glacier's movement. Similar to striations are chatter marks, lines of crescent-shape depressions in the rock underlying a glacier. They are formed by abrasion when boulders in the glacier are repeatedly caught and released as they are dragged along the bedrock. COUNT 4
QSN1 What cause glacial stiations? ANS1 large boulders that carve long scratches in the bedrock QSN2 What can scientists deduct from the direction of the striations? ANS2 direction of the glacier's movement QSN3 What are chatter marks? ANS3 lines of crescent-shape depressions in the rock underlying a glacier QSN4 How are chatter marks formed? ANS4 abrasion when boulders in the glacier are repeatedly caught and released