Glacial Landforms Flashcards
How do corries (cirques) form? (Give 5 facts)
• Nivation initially deepens a hollow.
• Rotational sliding increases abrasion, deepening the base.
• Plucking occurs at the back wall, forming a steep slope.
• A bergschrund (crevasse) forms, collecting debris that enhances erosion.
• Moraine deposition at the lip may form a tarn (corrie lake).
What are arêtes and pyramidal peaks?
• Arêtes: Narrow, steep ridges formed when two adjacent corries erode towards each other.
• Pyramidal Peaks: Sharp mountain peaks formed when three or more corries erode a single mountain (e.g., the Matterhorn).
What are glacial troughs and ribbon lakes?
• Glacial troughs (U-shaped valleys): Former V-shaped river valleys widened and deepened by glaciers.
• Ribbon lakes: Formed when glaciers over-deepen sections of valleys, which later fill with water.
What are hanging valleys? (Give 2 facts)
• Smaller tributary glaciers erode less deeply than the main glacier.
• After glaciation, the tributary valley is left hanging above the main valley, often with a waterfall.
What is a roche moutonnée? (Give 3 facts)
• Asymmetrical rock formations eroded by glaciers.
• Upstream side: Smooth, polished by abrasion.
• Downstream side: Jagged, plucked by the glacier.
What are crag and tail landforms?
• Crag: Resistant rock that protects softer rock from erosion.
• Tail: Depositional feature behind the crag (e.g., Edinburgh Castle on a crag and tail).
What are the 3(or 4) different types of moraines?
• Lateral Moraine: Forms along the edges of a glacier from debris falling off valley walls.
• Medial Moraine: Forms in the centre of a glacier when two glaciers merge.
• End Moraine (Terminal/Recessional): Forms at the glacier snout when ice melts and deposits sediment.
What are drumlins? (Give 3 facts)
• Oval-shaped hills of glacial till found in swarms (basket of eggs topography).
• Steep stoss end (facing ice movement) and gently sloping lee end.
• Exact formation is debated, but likely linked to ice deformation and sediment strength.
What is a till plain? (Give 2 facts)
• Extensive flat areas formed by glacial deposition.
• Composed of unsorted glacial till (boulders, clay, sand).
What are subglacial and ice-marginal landscapes?
• Subglacial: Formed under ice masses, dominated by erosion (e.g., glacial troughs).
• Ice-marginal: Formed at glacier edges, dominated by deposition (e.g., moraines).
What are proglacial and periglacial environments?
• Proglacial: Found in front of glaciers, where meltwater and wind action shape the landscape.
• Periglacial: Cold environments near but not under glaciers, featuring permafrost.
What are the three main scales of glacial landforms?
• Macro-scale: Large landforms (corries, glacial troughs, pyramidal peaks).
• Meso-scale: Medium landforms (drumlins, roches moutonnées).
• Micro-scale: Small features (striations, chattermarks, erratics).
