Glaciation Flashcards
When did glaciation happen
Ice advances or glaciation began 70 000 years ago and ended 10 000 years ago
What is an interglacial period
A warm period between glaciations
How does a glacier form
- Form in very cold places when lots of snow falls but doesn’t melt so there are layers of snow on top of each other
- Bottom layers of snow are compressed pushing air out and snow turns to ice forming a glacier
- Glacier gradually moves down slope due to gravity
How is V shaped valley formed
Before glaciation V shaped valley formed by river and during ice age the ice moves down the valley
Rock gets trapped in the bottom of ice and acts like sandpaper wearing away valley by abrasion
Glacier deepens, straightens and widens valley by abrasion
After ice me,t V shaped valley remains
What is a moraine
Material that has been carried and deposited by the glacier is called moraine
What is a terminal moraine
found at end point or furthest point reached by a glacier
What is a lateral moraine
Rocks found deposited alongside glacier
What is a ground moraine
Disorganised piles of rocks of various sizes and shapes and types found on ground
What is a medial moraine
Found at junction between 2 glaciers
What is a recessional moraine
Similar to terminal moraines but are found at the snout of the glacier where it remained at the same point for sufficient time
What is a drumlin
Glaciers move moraines around - a drumlin is a mound of deposited moraine - have a steep side and sloping side. Can be 1 km long or 50m in width or height
What are erratics
Large boulders carried by glacier and deposited in an area of different rock types so look out of place
What is frost shattering
Term to describe the Acton of glacial meltwater on joints, cracks and hollows in rock
What does abrasion mean
The moraine frozen into glacier grinds the valley sides and base like sandpaper (widening the valley)
What is plucking
Water at bottom of glacier freezes onto rock on valley base and as glacier moves the rock is pulled away
