Alpine Glaciation Flashcards

Glaciers and Their Origins

• Glaciers originate in mountainous areas at stream tributaries' headwaters, notably found in the Alps, Rockies, Andes, Himalayas, and more.

Functions of Glaciers

• Glaciers act as powerful agents of erosion, performing erosion, transport, and deposition of materials.

Zones of Glacial Activity

• Zone of Accumulation: Area where snow accumulates significantly.
• Zone of Ablation: Region where eroded materials are deposited.

Erosion Processes

• Abrasion: Smoothens valley floors and sides through continuous scraping action.
• Frost-Shattering: Loose materials fall onto glaciers, forming lateral moraines and contributing to englacial debris.
• Plucking (Quarrying): Ice adheres to rock and actively erodes it, resulting in a rugged landscape.
• Rotational Movement: Ice pivots and moves downhill, causing extensive overdeepening of glacier floors.

Landforms Created by Glaciers

• Cirque: A bowl-shaped depression with steep sides formed by glacial erosion.
• Horn: A pyramidal peak shaped by glacial erosion from multiple sides.
• Arete: A sharp ridge formed between two cirques.
• U-shaped Valley: Transformation of V-shaped valleys into broad, flat-bottomed U shapes due to glacial erosion.
• Fjord: An ocean inlet formed by melting glaciers in deep valleys.
• Hanging Valley: Leads to elevated cliffs where tributary glaciers erode at different rates compared to the main glacier.
• Truncated Spurs: Stumps of ridges eroded straight through by advancing glaciers.

Specific Glacier Features

• Roche Mountonnee: A rock formation shaped by glacial actions, marked by a smooth side facing ice flow and a jagged side resulting from plucking.
• Nunatak: Jagged mountain peaks that protrude above glacier surfaces, which remain rough due to lack of ice smoothing.
• Tarn: Small lakes formed in cirques from melting glaciers.

Glacial Transport and Deposits

• Glacial Transportation: Movement of eroded materials both within and above glaciers, also transported by meltwater.
• Striations: Indicator of glacial movement, shown as parallel scratches and grooves on rocks.
• Moraines: Deposited debris that forms specific types of landforms:
  • Lateral Moraine: Ridges formed along valley glacier edges.
  • Englacial Moraine: Material incorporated within the glacier ice and eventually forming ground moraine.
  • Terminal Moraine: Marks the furthest advance of a glacier.
  • Medial Moraine: Formed when two lateral moraines merge.
  • Recessional Moraines: Formed during pauses in glacier retreat.

Characteristics of Glacial Deposits

• Varve: Fertile sediment layer formed in glacial lakes.
• Erratics: Large boulders carried long distances by ice and deposited in areas with different bedrock.
• Ice-Dammed Lake: Bodies of water trapped by glaciers.
• Outwash Deposits: Material deposited by meltwater streams from glaciers.
• Outwash Plain: Created from extensive meltwater streams delivering sediment ahead of glaciers.
• Kame: Hills formed from sediment deposits at crevasses or depressions in glaciers.

Glacial Drift

• Drift: Collective term for all materials deposited under glacial conditions.
• Types of Glacial Drift:
  • Till: Unsorted materials including moraines and erratics.
  • Fluvioglacial Material: Sorted materials deposited by meltwater, such as varves.

Types of Glaciers

• Valley Glacier: Large ice masses that flow down existing valley paths, shaped by topography.
• Piedmont Glacier: Forms when valley glaciers move onto flatter areas, merging and spreading out.

Test your knowledge on alpine glaciation with these flashcards! Learn about where glaciers originate, their impact on erosion, and key concepts such as the zone of accumulation. Perfect for students of geology or anyone interested in earth sciences.