Glaciation Keywords and Concepts
GLACIATION KEYWORDS
Glaciation Overview
- Glaciation: The process where large masses of ice (called glaciers) move across the land, shaping it by eroding, transporting, and depositing materials.
Definitions and Concepts
- Glacier: A river of moving ice.
- Boulder Clay (Till): A mixed sediment left behind by a glacier when it melts, consisting of clay, rocks, and sand. Covers large areas of land and is beneficial for farming.
- Cirque: A bowl-shaped hollow found at the top of a mountain formed when a glacier begins to erode the mountain.
- U-Shaped Valley: A valley shaped like the letter "U" carved out by a glacier, characterized by steep sides and a flat bottom, in contrast to a V-shaped river valley.
- Ribbon Lake: A long, narrow lake formed in a U-shaped valley where the glacier erodes the valley floor more deeply in certain areas, creating a lake.
- Paternoster Lakes: A series of small, connected lakes that form in a glacial valley, resembling a string of beads.
- Erratics: Large boulders picked up and carried by a glacier, often found resting on land where the surrounding rocks are different.
- Plucking: The process where a glacier moves over the land, pulling and lifting rocks out of the ground. These rocks become embedded in the ice and are transported away.
- Moraine: A pile of rocks and soil deposited by a melting glacier. There are four types:
- Lateral Moraine: Found on the sides of a glacier.
- Medial Moraine: Formed from lateral moraines of two glaciers meeting.
- Terminal Moraine: Located at the end of a glacier.
- Ground Moraine: Spread out beneath the glacier. - Corrie Lake (Tarn): A small lake that forms in a cirque after the glacier melts, collecting water from rain or melting snow.
- Pyramidal Peak: A sharp, pointed mountain peak formed through the erosion of a mountain by three or more glaciers from different sides.
- Hanging Valley: A small valley that remains elevated above the main U-shaped valley, formed when a smaller glacier meets a larger one.
- Truncated Spurs: Interlocking spurs that are cut off or "truncated" by a glacier as it moves through a valley.
- Drumlin: A smooth, egg-shaped hill made from boulder clay formed beneath a glacier as the glacier pushes the material into hills while moving.
- Abrasion: The process where the movement of the glacier scrapes the ground beneath it, similar to sandpaper rubbing on wood, leading to the smoothing of surfaces.
- Outwash Plain: A flat area of land consisting of sand and gravel that is washed out from the melting glacier by streams of water.
Additional Concepts
- Arêtes: Sharp, narrow ridges of rock that form between two cirques or valleys, created by the erosion of two glaciers acting from opposite directions.
- Fjords: Deep, narrow coastal valleys filled with seawater, characterized as U-shaped valleys that were eroded by glaciers and subsequently flooded by the sea.
- Esker: A long, winding ridge made up of sand and gravel, formed by rivers flowing inside or beneath glaciers.