Glaciation Terms

Question 1

Abrasion

Answer 1

Erosion caused by rocks and boulders in the base of the glacier acting like a giant file scratching and scraping the rocks below.

Question 2

Arête

Answer 2

A sharp, knife-like ridge formed between two corries cutting back by processes of erosion and freeze thaw.

Question 3

Bulldozing

Answer 3

Ice pushes material of all shapes and sizes as it moves slowly forward.

Question 4

Conservation

Answer 4

Managing the environment in order to preserve, protect or restore it.

Question 5

Corrie

Answer 5

(Also called cirque) Armchair- shaped hollow in the mountainside formed by glacial erosion, rotational slip and freeze thaw weathering. This is where the valley glacier begins. When the ice melts, it can leave a small circular lake called a tarn.

Question 6

Drumlin

Answer 6

A hill made of glacial till deposited by a moving glacier, usually elongated or oval in shape, with the longer axis parallel to the former direction of ice.

Question 7

Erratics

Answer 7

Rocks which have been transported and deposited by a glacier some distance from their source region.

Question 8

Freeze-thaw weathering

Answer 8

(Also called frost-shattering) It occurs in cold climates when temperatures are often around freezing point and where exposed rocks contain many cracks. Water enters the cracks during the warmer day and freezes during the colder night. As the water turns into ice it expands and exerts pressure on the surrounding rock, causing pieces to break off.

Question 9

Glacial trough

Answer 9

A river valley widened and deepened by the erosive action of glaciers; it becomes ‘U’-shaped instead of the normal ‘V’-shape of a river valley.

Question 10

Hanging valley

Answer 10

A tributary valley to the main glacier, too cold and high up for ice to be able to easily move. It therefore was not eroded as much as the lower main valley, and today is often the site for a waterfall crashing several hundred metres to the main floor.

Question 11

Land use conflicts

Answer 11

Disagreements which arise when different users of the land do not agree on how it should be used.

Question 12

Moraine

Answer 12

Frost-shattered rock debris and material eroded from the valley floor and sides, transported and deposited by glaciers.

Question 13

Outwash

Answer 13

Material, chiefly sand or gravel, deposited by meltwater streams in front of, and underneath, a glacier. The material is sorted and rounded by water action.

Question 14

Plucking

Answer 14

A type of erosion where melt water in the glacier freezes onto rocks, and as the ice moves forward it plucks or pulls out large pieces along the rock joints.

Question 15

Pyramidal peak

Answer 15

Where several corries cut back to meet at a central point, the mountain takes the form of a steep pyramid.

Question 16

Ribbon lake

Answer 16

A long, narrow lake found in glaciated valleys formed in locations where the glacier had more erosive power, eg in areas of softer rock, where the valley gradient temporarily steepened or a tributary glacier joined the main valley.

Question 17

Rotational slip

Answer 17

This occurs when the ice moves in a circular motion. This process can help to erode hollows in the landscape, and deepen hollows into bowl shapes.

Question 18

Till

Answer 18

An unsorted mixture of sand, clay and boulders carried by a glacier and deposited as ground moraine over a large area.

Question 19

Truncated spur

Answer 19

A former river valley spur which has been sliced off by a valley glacier, forming cliff like edges.