Glacial striations
From Wikipedia, the free encyclopedia
Glacial striations or glacial grooves are scratches or gouges cut into the bedrock by process of glacial abrasion during one of the Earth's Ice Ages or by mountain glaciers. Striations usually occur as multiple straight, parallel lines representing the movement of the sediment-loaded base of the glacier. Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut the grooves, and finer sediments also in the base of the moving glacier further scour and polish the bedrock.
Alongside being useful evidence of the direction in which a glacier has flowed, the depth and extent of weathering of the gouges are also used to provide some indication as to when the glacier passed over the area.
Glacial striations can be found at the Glacial Grooves in National Natural Landmark, Kelleys Island, Ohio, the most impressive of which is 400 feet long, 35 feet wide, and up to 10 feet deep.
[edit] External links
