Context: 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.

Question: What cause glacial stiations?
Answer: large boulders that carve long scratches in the bedrock

Question: What can scientists deduct from the direction of the striations?
Answer: direction of the glacier's movement

Question: What are chatter marks?
Answer: lines of crescent-shape depressions in the rock underlying a glacier

Question: How are chatter marks formed?
Answer: abrasion when boulders in the glacier are repeatedly caught and released

Question: What charactrerizes glacial striations?
Answer: Unanswerable

Question: What is formed when glaciers lack boulders?
Answer: Unanswerable

Question: What helps scientists determine the speed of a glacier?
Answer: Unanswerable

Question: What is formed when glaciers crush boulders?
Answer: Unanswerable