Glacial Systems and Landscapes Definitions

Question 1

Ablation

Answer 1

The loss of mass from the glacier, e.g. meltwater, avalanches, sublimation, evaporation.

Question 2

Abrasion

Answer 2

Small rocks within the base of the glacier rub against the bedrock.

Question 3

Accumulation

Answer 3

The addition of mass to the glacier, usually as snow.

Question 4

Active layer

Answer 4

The top layer of soil above permafrost, which thaws annually in summer.

Question 5

Alpine regions

Answer 5

Areas of low temperature in high altitude, mountainous regions.

Question 6

Arêtes

Answer 6

A ridge formed between two corries.

Question 7

Basal ice melting

Answer 7

The weight of a temperate glacier causes meltwater, which will then erode the
bedrock through fluvial erosion.

Question 8

Basal Sliding

Answer 8

Glaciers sliding over bedrock, due to meltwater between the two surfaces.

Question 9

Blockfields

Answer 9

Rock-strewn landscape caused by extensive frost action.

Question 10

Cold based glaciers/ Polar glaciers

Answer 10

The glacier’s temperature remains below zero

degrees, so the base of the glacier remains frozen and moves very little.

Question 11

Compressional flow

Answer 11

Ice builds up and thickens due to friction as a glacier travels upwards along
a shallow gradient

Question 12

Corries

Answer 12

A round hollow in the side of a hill, widened from an initial smaller hollow by a glacier
within the hollow.

Question 13

Crushing

Answer 13

The weight of the glacier causes fracturing in the bedrock.

Question 14

Drumlins

Answer 14

When a glacier hits an obstacle that cannot be eroded, deposition from underneath the
glacier builds up behind the obstacle.

Question 15

Environmental fragility

Answer 15

An environment is vulnerable or at risk, with low resilience or ability to
adapt to changes.

Question 16

Erratics

Answer 16

Boulders transported and deposited by a glacier. The type of rock that forms the erratic
will usually differ from the rock types in the surrounding landscape.

Question 17

Esker

Answer 17

A long, winding ridge of glacial deposition.

Question 18

Extensional flow

Answer 18

Ice thins out, creating crevasses, due to an increase in the glacier’s velocity
down a shallow gradient.

Question 19

Fluvial erosion

Answer 19

Water within the glacier erodes the base of the glacier over time through:
hydraulic action, attrition, corrosion.

Question 20

Frost heave

Answer 20

The freezing and expansion of water beneath the ground, resulting in floor uplift.

Question 21

Glacial budget

Answer 21

The difference between accumulation and ablation for a glacier

Question 22

Glacial period

Answer 22

A period of time of colder average global temperatures causing the growth of ice
cover, glacial advances and sea levels to fall.

Question 23

Glacial through

Answer 23

A U-shaped valley formed from a v-shaped river valley that becomes filled and
eroded over time by a glacier.

Question 24

Hanging valley

Answer 24

A valley with a wall at one end, due to the glacier that filled the valley previously
being low energy.

Question 25

Holocene epoch

Answer 25

Our current glacial period of limited ice cover, lasting over 10,000 years.

Question 26

Ice wedge

Answer 26

Water infiltrates small cracks in the permafrost and expands on freezing repeatedly.

Question 27

Interglacial period

Answer 27

A period of time of warmer average global temperatures, resulting in reduced ice cover, glacial retreat and sea levels to rise.

Question 28

Glacial deformation

Answer 28

Glacial movement caused by the weight of the glacier above deforming the ice.

Question 29

Kames

Answer 29

Piles of material, sorted due to the differing weight of sediment, left on the valley floor after a glacier melts.

Question 30

Milankovitch cycles

Answer 30

Changes to the tilt and shape of the orbit will affect the average temperature of the Earth.

Question 31

Meltwater channels

Answer 31

Streams of meltwater (melted glacier) formed by higher temperatures.

Question 32

Morraines

Answer 32

Deposits of eroded material that has been transported by a glacier. Moraines may be lateral, medial, ground, recessional or terminal.

Question 33

Nivation

Answer 33

Erosional processes involving snow and ice.

Question 34

Orbital eccentricity

Answer 34

How far a planet’s orbit is from being a perfect circle.

Question 35

Outwash plain

Answer 35

Material is washed out and deposited due to large volumes of meltwater as a glacier recedes.

Question 36

Patterned ground

Answer 36

Patterned ground is formed through the frost heave of stones in and underneath the active layer

Question 37

Periglacial

Answer 37

Landscapes found at the edge of glacier, polar and alpine regions. Permafrost occurs, with low precipitation and only highly adapted plant species survive.

Question 38

Permafrost

Answer 38

Permanently frozen soils for two or more consecutive years

Question 39

Pingos

Answer 39

A mound produced as ground is forced upwards through frost heave.

Question 40

Plucking

Answer 40

Rocks on the bedrock are frozen within the glacier. As the glacier moves, the rocks are pulled from the bedrock and moved.

Question 41

Polar regions

Answer 41

Areas of maximum ice sheets and limited vegetation, located at high latitudes on Earth.

Question 42

Roches moutonnées

Answer 42

Rock shaped by a glacier flowing over it and eroding it.

Question 43

Solifluction

Answer 43

The movement of waterlogged soil, trapped between the active layer and permafrost.

Question 44

Solifluction lobes

Answer 44

As the active layer thaws, soil falls down the hillside in tongue-shaped lobes.

Question 45

Terracettes

Answer 45

Ridges running parallel across a hillside, believed to be created by vegetation trapping sediment falling loose down the hillside, created through frost heave.

Question 46

Thermokarst

Answer 46

Marshy, boggy wetlands caused when permafrost melts.

Question 47

Till plains

Answer 47

An ice sheet detaches from the main glacier and melts, releasing all loose till and sediment across the bedrock.

Question 48

Warm based glacier/ Temperate glacier

Answer 48

Faster travelling glaciers due to basal | meltwater trapped underneath the glacier, acting as lubrication to allow the glacier to move.