Glossary: Ice On The Land

Question 1

Arête.

Answer 1

Sharp-edged two-sided ridge on the top of a mountain.

Question 2

Basal Sliding.

Answer 2

The act of a glacier sliding over the valley floor, due to melt water under the ice acting as a lubricant.

Question 3

Boulder clay.

Answer 3

The name given to all materials deposited by ice; usually it is clay containing boulders of different sizes within it.

Question 4

Erratic.

Answer 4

Boulders found on the surface that are different from the rock below.

Question 5

Firn.

Answer 5

Crystalline or granular snow found on the upper part of a glacier, where it has not yet been compressed into ice.

Question 6

Glacial trough.

Answer 6

The flat-floored and steep-sided valley formed by a glacier, often also referred to as a U-shaped valley.

Question 7

Ground moraine.

Answer 7

Surface deposits left by glaciers and ice sheets; the surface formed is uneven and hummocky.

Question 8

Ice cap.

Answer 8

A smaller body of ice (less than 50,000km2) usually found in mountainous regions.

Question 9

Ice sheet.

Answer 9

A large body of ice over 50,000km2 in extent, usually covering all the land in an area.

Question 10

Abrasion (glacial).

Answer 10

A process of erosion in which rocks carried in the bottom of the ice wear away the surface rock over which the the ice passes.

Question 11

Lateral moraine.

Answer 11

Pile of scree and boulder clay deposited in a line along the sides of a valley.

Question 12

Medial moraine.

Answer 12

Pile of loose material carried and deposited in the centre of the ice.

Question 13

Milankovitch Cycles.

Answer 13

A theory that describes the collective effects of changes in the Earth’s movements upon its climate.

Question 14

Misfit stream.

Answer 14

Small river which flows over the wide floor of a glaciated valley; its size is out of scale with that of the valley.

Question 15

Moraine.

Answer 15

All materials deposited after having been transported by ice.

Question 16

Pleistocene.

Answer 16

Geologists’ name for the last Ice Age when ice covered much larger areas of Europe, North America and Asia than it does today (1.8 million to ~ 10,000 years ago).

Question 17

Plucking.

Answer 17

A process of erosion in which blocks of rock are torn away from the bed rock as the ice moves away.

Question 18

Striations.

Answer 18

Deep grooves and scratches on surface rocks made by the sharp edges of stones carried in the bottom of the ice.

Question 19

Terminal moraine.

Answer 19

Pile of boulder clay in a line across the valley or lowland, dumped by the ice at the furthest point reached.

Question 20

Till (glacial).

Answer 20

All materials deposited by ice; it is an alternative term for boulder clay.

Question 21

Valley glacier.

Answer 21

A moving mass of ice confined within a valley.

Question 22

Corrie.

Answer 22

A circular ‘armchair-shaped’ rock hollow high on a mountainside, surrounded by steep and rocky walls but with a rock lip on the open side.

Question 23

Drumlins.

Answer 23

Egg-shaped hills made of boulder clay up to 40m high and 400m long; many usually occur together forming ‘baskets of eggs’ scenery.

Question 24

Hanging Valley.

Answer 24

A tributary valley left high above the main valley floor so that its stream flowing down the main valley sides falls as a waterfall.

Question 25

Pyramidal peak.

Answer 25

Three-sided slab of rock which forms a mountain peak.

Question 26

Ribbon lake.

Answer 26

Long and narrow lake in the floor of a glaciated valley.

Question 27

Rock basin.

Answer 27

Hollow in the valley floor eroded by a valley glacier.

Question 28

Tarn.

Answer 28

Circular lake in a corrie hollow eroded by a glacier.

Question 29

Truncated spurs.

Answer 29

Higher areas on the straight rocky sides of the glaciated valley.