Glaciation Flashcards
What is an inter- glacier?
Is a period of time between two ice ages
What is an ice sheet
Is a mass of glacial ice extending more than 50000 km2
What is an example of a famous glacier
Merdeglace french Alps
Hat dose crevasse mean?
A deep crack found in an ice sheet or glacier
What is this glacier system?
Look at notes…
What is an ice age?
An ice age is a period of time when prolonged low temperatures mean that waterthrush to ice over a large area
What are inputs?
Inputs come from avalanches along sides of the glacier but mainly from precipitation as snow
What is storage?
Over time snow accumulates and is compressed into ice. The water held in storage is the glacier
What is flow?
Under the force of gravity the glacier flows down hill
What is an output?
Meltwater is the main output from the glacier, along with some evaporation
What is abrasion?
A type of weathering where water repeatedly freezes and puts pressure on rocks to break them down
Plucking is…
A process of erosion where glacier ice freezes onto rocks and, as it moves away pulls large pieces of rocks with it
What is an avalanche
A mass of snow and ice that moves very quickly down an mountain side
Causes of Avalanche …
Heavy snowfall
Steep slop
Pressure by skiers
Give seven ways to reduce the affect of avalanches:
Walls & fences on steep slops to hold back snow.
Plant trees to break up small avalanches.
Wedges to protect electricity pylons.
Sheds to protect railway line.
Mounds on flatter ground to slow down. avalanches as it reaches flatter ground.
What is a Corrie?
A glacial feature formed from errosion
How does a Corrie form (4 points)?
- Snow collects in a hallow on a side of a mountain.
- Over time, further snow collects in hallow and compresses snow below turning it into ice.
- Hollow deepens and widens through abrasion and plucking.
- Leads to ‘arm chair’ shape characteristic of a Corrie and causes rock lip to be formed.
What can form after the glacier has disappeared and what is it called?
Lake can form in the hallow, this is called a Tarn
What is a Arête?
a knife-edged ridges formed between two corries
What are tuncated spurs?
interlocking spurs that have been truncated
What are hanging valleys?
when glaciers erode deeper into the valley, tributaries are left higher up the sides, they are left hanging
What is a ribbon lake?
lakes formed in soft rock which are carved out by glaciers that then melt e.g. lake windermere.
What is a Drumlin
forms of a till, elongated features that can reach a kilometre or more in length, 500 m in width and 50m high.
What is the accepted idea about how Drumlins are formed?
Formed when ice became overloaded with sediment.
Features of glacial deposition
Medial moraine - found in the centre.
Laterial moraine - produced from frost shattering off the valley sides and is carried at the sides of the glacier.
Terminal moraine - found at snout and marks the max advance of a glacier.
Ground moraine - formed beneath a glacier and forms part of the valley floor.
What are Erratics and how are they formed?
A boulder that is different from the bedrock beneath it. They are transported and deposited by glaciers. Useful indicators of patterns of former ice flow.
Example of an pyramidal peck…
Matterhorn
