OCR A-Level Geography H481
Coastal Landscapes
Glaciated Landscapes
Dryland Landscapes
Earth’s Life Support Systems
Changing Spaces; Making Places
Trade in the Contemporary World
Global Migration
Human Rights
Power and Borders
Climate Change
Disease Dilemmas
Exploring Oceans
Future of Food
Hazardous Earth
Geographical Skills
Glaciated Landscapes
Glacial erosion and the marks it leaves on rock
- 3 things to know
- Component 01
Overview
Recall questions on abrasion and plucking, rock flour and striations, reading ice direction from roches moutonnées, crag and tail, whalebacks, knock and lochan topography, erosion by subglacial meltwater, and why thicker ice erodes faster.
What you need to know
Answer each one before you reveal it.
What is plucking?
Why is plucking most effective on well-jointed rock?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is abrasion?
Model answer
It is the wearing away of bedrock by rock debris held in the base of the ice and dragged across the surface, acting like sandpaper.
- 2
Name three conditions needed for effective abrasion.
Model answer
Debris-rich basal ice, a glacier that is sliding over its bed, and enough ice thickness to press the debris against the rock.
- 3
What is plucking?
Model answer
Meltwater freezes onto jointed bedrock and, as the glacier moves on, blocks are torn away and carried off with the ice.
- 4
Why is plucking most effective on well-jointed rock?
Model answer
The joints already divide the rock into blocks, so the ice needs only to freeze on and pull them out rather than break intact rock apart.
- 5
What is rock flour?
Model answer
It is the very fine, silt-sized rock powder produced by abrasion, which gives meltwater streams and glacial lakes their milky, turquoise colour.
- 6
What are striations?
Model answer
They are scratches and grooves cut into bedrock by angular debris dragged across it in the base of a glacier.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Glaciated Landscapes, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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