Glacial Processes Flashcards
All 9 cards in this deck
What is abrasion?
Rocks trapped beneath the glacier scratch and smooth the bedrock underneath, leaving striations.
What is plucking?
Rocks freeze into the base and sides of the glacier, and as the ice moves it tears them away from the ground.
What are the steps of freeze-thaw weathering?
e.g. a crack in exposed rock above a glacier- By day snow melts and water enters the crack — the crack fills with water.
- Temperature falls below 0°C, the water freezes and expands by about 9% — the crack is widened.
- The process repeats — pieces of rock break off and fall onto the glacier.
What is bulldozing by a glacier?
Rocks and debris in front of the glacier are pushed downhill by the sheer force of the moving ice.
What is rotational slip?
The movement of ice in a circular motion within a hollow, deepening the hollow to form a corrie.
What is the difference between till and outwash?
Till is dropped directly by the ice and is angular and unsorted; outwash is carried out by meltwater streams and is sorted into different sizes.
Why is material deposited by a glacier mixed in size and shape?
Ice is solid, so it carries everything from fine debris to large boulders and bulldozes all material in its path.
True or false? A glacier deposits its load mainly because the ice is melting.
True. As the ice melts it can no longer carry its load, so debris is dropped.
True or false? Plucking and abrasion are processes of weathering.
False. They are processes of glacial erosion; freeze-thaw is the main weathering process.