How glaciers form and move, and the landforms left behind by glaciation, from an intro geology course.
30 cards · basic cards · AI-written, checked twice. Edit anything.
- What is a glacier?
- A large, persistent mass of ice and snow that flows under its own weight.
- What three stages transform snow into glacial ice?
- Accumulation (snow falls), compaction (weight increases density), recrystallization (ice crystals grow larger and air is expelled).
- What is neve?
- Compacted granular snow intermediate between snow and glacial ice, with density between the two.
- Define equilibrium line altitude (ELA).
- The elevation where annual accumulation equals annual ablation on a glacier's surface.
- What is a valley glacier?
- A glacier confined to and flowing down a mountain valley, also called an alpine glacier.
- What is a continental glacier?
- A large ice sheet covering vast continental areas, such as those presently in Greenland and Antarctica.
- What is a piedmont glacier?
- A glacier formed where valley glaciers emerge from mountain valleys and merge on the adjacent plains.
- What is a cirque glacier?
- A small glacier occupying a bowl-shaped or amphitheater-shaped depression in high mountains.
- How does plastic flow move a glacier?
- Ice at depth deforms under pressure and flows plastically downslope without melting, like very slow viscous flow.
- What is basal sliding?
- Glacial movement in which ice at the base of a glacier lubricates and slides over bedrock, typically when meltwater is present.
- What is a glacial erratic?
- A large boulder transported by glacial ice and deposited far from its source rock outcrop.
- What is a cirque?
- A bowl-shaped or amphitheater-shaped depression carved by glacial erosion at the head of a mountain valley.
- What is a U-shaped valley?
- A valley with steep walls and a flat floor, carved by glacial erosion, contrasting with V-shaped river valleys.
- What is a hanging valley?
- A tributary valley whose floor is higher than the main glacier valley it joins, often with a waterfall where they meet.
- What is a moraine?
- A ridge or mound of sediment deposited directly by glacial ice, containing unsorted, unstratified material.
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