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Geography Chapter 17
Term | Definition |
---|---|
Glacier | A large mass of ice that forms on land and moves slowly downhill under its own weight |
Snowline | A temporary line marking the elevation where winter snowfall persists throughout the summer |
Alpine Glacier | A long, narrow glacier that forms high in a mountain valley |
Continental Glacier | Continuous masses of ice; larger than alpine glaciers |
Cirque | A semi-circular shaped bedrock feature created as glaciers erode a mountain |
Ice sheet | A continuous mass of unconfined ice |
Glacial Surge | The forward movement of a glacier at faster than normal speeds |
Abrasion | As the glacier flows downhills, boulders frozen to its bottom move with it and scrape the bedrock, leaving gouges and scratches |
Plucking | As the glacier flows downhill, boulders are picked up, freeze to the bottom of the glacier, and are carried downhill |
Roche Moutonnée | An asymmetrical hill of exposed bedrock with a gently sloping side. Polished smooth by a glacier |
V Shaped Valley | Formed by a flowing river |
Arete | A sharp ridge separating two cirques |
Col | The lowest point between two peaks or horns |
Horn | A pyramid-shaped mountain peak. Created by multiple glaciers eroding the same mountain |
U Shaped Valley | A valley shaped like a U formed as a glacier erodes the land |
Striations | Scratches on rock surfaces caused by the movement of an ice sheet carrying material |
Tarn | Small mountain lakes found in cirques |
Fjord | A U shaped valley cut by a glacier and then filled in by the rising sea level |
Glacial Drift | The general term for all glacial deposits |
Moraine | A landform created by glacial deposition; till deposited at the edges of a glacier as it moves or melts |
Lateral Moraine | A ridge of till deposited at the sides of a glacier |
Medial Moraine | A ridge of till in the middle of a glacier, usually when two glaciers meet |
Terminal Moraine | A ridge of till at the furthest point reached by the glacier |
Till Plain | A large, relatively flat plain of unsorted glacial deposits behind a terminal moraine |
Drumlin | Elongated, teardrop-shaped hills of rock, sand, and gravel that formed under moving glacier ice |
Outwash Plain | An area of glacial stream deposits beyond a glacier's moraines |
Esker | Narrow ridges made of sand and gravel. Formed by glacial meltwater flowing within and under glaciers |
Kame | Small hill, knoll or mound of sorted sand and gravel left on a surface as a glacier retreats |
Kettle / Kettle Lake | A small depression formed by a chunk of ice in glacial till. The ice melts, and either a depression is left, or the depression fills with water and becomes a lake |