Glaciation Flashcards
Name 3 landforms of glacial erosion
Corrie
Truncated Spur
Roche Moutonee
How is a Roche Moutonee formed?
Resistant rock, causes ice creep and regelation around it. As ice slides over the rock, it scores and smooths the stoss, while refreezing on the lee, which causes plucking.
How are truncated spurs formed?
Valley glaciers, are less flexible than rivers. The glaciers remove ends of interlocking spurs by plucking and abrasion as they move down the river valley.
How is a Corrie formed?
Large rounded “armchair like depression” is eroded and deepened by plucking and abrasion due to the rotational ice movement of a cirque glacier.
How is a pyramidal peak formed?
If 3 Corries erode back towards one another, this forms a pyramidal peak.
Exploited periglacial landscape case study
Yamal Peninsula
Located in Siberia Russia.
Home to Nenets.
Environmental Values:
Carbon and Methane store.
Cultural Values:
Nenet people
Economic:
Home to biggest known gas reserve which is being exploited by Gazprom (State owned Russian Oil company)
Name 5 Economic, Cultural and Environmental values of glacial and periglacial landscapes
Economic:
- Forestry
- Tourism
- Mineral Stores
- Hunting and fishing for food and clothing
- Renewables e.g HEP
Environmental:
- Carbon Sequestration
- Weather System Control
- Climate Control
- Fragile Ecosystems
- Genetic Diversity
Cultural:
- Scientific Research e.g ice core analysis
- Leisure and recreation
- Spiritual and Religious purposes
- Native people with distinctive cultures
Name 5 human and 5 natural threats facing active and relict glacial landscapes
Natural:
Avalanches and mass movement
Natural Climate change
Steep rugged terrain
Seasonal Extremes
Glacial Outburst floods Jökulhlaup
Human:
Footpath trampling from Tourists
Introduction of invasive species
Noise pollution from mining or tourists
Overfishing
Anthropogenic Climate change
Name causes of natural climate change
Milankovitch Cycles
- Eccentricity
- Precession of Equinoxes
- Obliquity
Volcanic Emissions
Sun Spots e.g Maunder minimum
Name all periglacial processes and a brief overview
Freeze Thaw Weathering
- Water freezes in cracks and joints of rocks, expands by up to 10%, weakening the rock and repeated freezing and thawing will break the rock up.
Solifluction
- The downslope movement of the saturated active layer under the influence of gravity, known as gelifluction when it occurs over impermeable permafrost
Nivation
A combination of processes weakens and erodes the ground beneath a snow patch. Processes include: Freeze thaw, solifluction, meltwater erosion.
Frost Heave
The freezing and expansion of soil water, results in the upward movement and dislocation of soil and rocks. As the ground freezes, large stones become chilled more rapidly than the soil. Water below these stones, freeze and expand pushing the stone upwards due to permafrost below. The result is the formation of small domes on the ground surface
Groundwater freezing
Water is able to filter down into the upper layers of the ground and then freeze, the expansion of the ice causes the overlying sediments to heave upwards into a done, as high as 50m.
Ground contraction
When dry areas of the active layer refreeze, ground contracts and cracks. Ice wedges will form when meltwater enters during summer and freezes during winter. Repeats and widens and deepens the ice wedge.
Aeolian Action
Limited vegetation cover, wind picks up dry, loose sediment.
Meltwater erosion
During summer, meltwater erodes stream or river channels. Refreezing at the onset of winter causes a reduction in discharge and sediment deposition in the channel
What are the features of a tundra?
Tundra, has little vegetation. High levels of permafrost, resulting in impermeable surfaces, and a smaller active layer = when winter freezes active layer the water is trapped and melts in the summer… Low evaporation occurs in this biome, resulting in very wet, boggy, saturated soil. No percolation due to permafrost… holds significant amounts of water due to these features.
How do Tundra’s link to Carbon?
Tundra is very saturated, therefore there are a lot of bodies of water providing anaerobic conditions. Peat, if it is dried out due to anthropogenic climate change, or human exploitation, the peat is no longer under anoxic conditions. This results in the formation of CO2, contributing to climate change, increasing temps and humidity… resulting in more rainfall and ultimately changes the water cycle.
Name the terms for
On top of a glacier
Inside a glacier
Underneath a glacier
Near/Around a glacier
Supraglacial
Englacial
Subglacial
Periglacial
Name 4 landforms of glacial deposition
Drumlins : Highly distinctive, contains unsorted and angular till!
Moraines, Medial Moraines, Lateral Moraine, Terminal Moraine, Recessional:
Lateral = A ridge of till deposited along the valley sides
Medial moraine = A ridge of till deposited in the middle of the valley (parallel to to valley sides)
Terminal moraine = A high ridge of till extending across a valley at right angles to the valley sides, represents the maximum limit of a glacier
Recessional moraine = A lower ridge of till across the valley, parallel to the terminal moraine.
What erosional and depositional landforms can be mapped to indicate the direction of ice movement?
Erosional:
- Striations
- Roche Moutonee
- Glacial Trough
- Crag and Tail
Depositional:
- Drumlins
