Glacier systems and Landforms Flashcards
What is a glacier?
A large mass of perennial ice
- resting on land or floating in water
- formed due to multiyear surplus of snowfall
What are the two types of glaciers?
Alpine glaciers
Continental glaciers
What is a valley glacier?
- Rivers of ice, confined in valleys
- transports debris downstream
Cirque Glacier?
Bowl-shaped pit located at the head of a valley
-Eroded during times of more extensive glaciation
Piedmont glacier
Formed by coalescing (growing,fusing together) valley glaciers - No confining valley
Tidewater glacier
Terminate in a body of water
Continental glacier
Continental glaciers are continuous masses of ice that are much larger than alpine glaciers. Small continental glaciers are called ice fields. Big continental glaciers are called ice sheets. Greenland and Antarctica are almost entirely covered with ice sheets that are up to 3500 m (11 500 ft) thick.
4 zones of Glaciers?
- Accumulation Zone
- Firn
- Equillibrium line
- Ablation zone
What is glacier mass balance?
Change in the mass of a glacier overtime
why do glaciers move? 2 major reasons
- Weight
- Flow
What does glacial ice velocity depend on?
- Distance from bed and valley sides (friction)
- Surface slope (steepness)
- Free water at the bed (lubrication)
elastic/Placstic deformation
elastic deformation is a change in shape of a material at low stress that is recoverable after the stress is removed.
Supraglacial melt water
- Water flow on top of a glacier
- melts surface and can melt through the glacier
How is subglacial meltwater formed?
1) At the surface - flows through moulins and tunnels to the bed
2) By friction of ice moving over the bed
What does subglacial meltwater do to the glacier?
- Increases slip as the bed is lubricacted
- Erodes and transports sediment
