glacial Flashcards
how much of the uk was covered in ice 20,000 years ago
Scotland, Ireland and Wales, as far south as the Bristol Channel
freeze-the weathering
water gets into the cracks in the rocks. The water freezes and expands putting pressure on the rock. The ice then thaws, releasing the pressure, this will weaken the rock, making it vulnerable
abrasion
bits of rock stuck in the ice grind against the rock below the glacier wearing it away
plucking
meltwater at the base, back or sides of a glacier freezes onto rock. As the glacier moves forward it pulls out pieces of rock
rotational slip
the ice at the top of the glacier moves in a circular motion. this can erode hollows in the landscape and deepen them into bowl shapes
bulldozing
when glaciers push loose material ahead of them, it is called bulldozing
what is the material that glaciers move called
till
landforms formed by erosion - 7
-corries
-aretes
-pyramidal peaks
-truncated spurs
-glacial troughs
-ribbon lakes
-hanging valleys
arete formation
narrow, steep-sided ridge formed when 2 glaciers flow in parallel valleys. The glaciers erode the sides of the valleys, sharpening the ridge between them
corries formation
start as hollows containing a small glacier. As rotational slip occurs, the hole is eroded into a steep-sided armchair shape with a lip at the bottom. When the ice melts, it leaves a tarn
pyramidal peak formation
pointed mountain peak with t least 3 sides. It’s formed when 3 or more back-to-back glaciers erode a mountain
truncated spurs formation
cliff-like edges on the valley side formed when ridges of land that stick out into the main valley are cut off as the glacier moves past
formation of glacial troughs
steep sided valleys with flat floors. they start off as a v-shaped river valley but change to a u-shape as the glacier erodes the sides and floor making it deeper and wider
formation of ribbon lakes
long, thin lakes that form after a glacier retreats. They form in hollows where softer rock was eroded more than the surrounding hard rock
formation of hanging valleys
valleys formed by small tributary glaciers that flow into a main glacier. the glacial trough of the large glacier is eroded much more deeply, so when all of the glaciers melt, the tributary valleys are at a higher level