Glaciation

Question 1

Define glacier.

Answer 1

Ice that moves downhill under gravity. They replace rivers in valleys. They transport large amounts of material. As this slides downhill, it erodes the land.

Question 2

Name 3 processes of glacial erosion.

Answer 2

Freeze-thaw weathering, abrasion and plucking.

Question 3

Describe freeze-thaw weathering.

Answer 3

Water fills a crack in the rock.
The water freezes and the crack is made wider.
When the ice melts, the pressure is released.
Repetition of this widens the cracks and causes pieces of rock to fall off.

Question 4

Describe plucking.

Answer 4

Ice freezes and sticks of rock.

When the ice moves, pieces of rock break off with it.

Question 5

Describe abrasion.

Answer 5

Material carried by a glacier acts like sandpaper, rubbing against and wearing away sides and floor of a valley.

Question 6

What is a corrie?

Answer 6

A hollow that formed at the start of the Ice Age. Snow collects in them and turns into ice and then slides downhill. Loose rock drags across the valley and the ice erodes the valley.

Question 7

What is an arete?

Answer 7

When two or more corries develop next to each other, they erode towards each other. The land between them gets narrower until a sharp ridge is formed.

Question 8

What is a pyramidal peak?

Answer 8

When 3 or more corries cut backwards into the same mountain.

Question 9

What is an Ice Age?

Answer 9

When ice and snow covered the whole world for many years.

Question 10

What is a U-shaped valley?

Answer 10

Glaciers followed the route of V-shaped river valleys. These were small, shallow and winding.
Plucking, abrasion and freeze-thaw weathering eroded the sides of the valley.
The valley became wider, deeper, steeper and straighter.
When the ice melted, moraine is dumped and make a flat valley floor. The river that returns is called a ‘misfit stream’ because it does not fit the valley.

Question 11

What is a truncated spur?

Answer 11

Truncated spurs are when the ends of interlocking spurs are eroded by glaciers.
They are cliffs or cut-off ridges.

Question 12

What is a hanging valley?

Answer 12

When a tributary river is not eroded, it is left hanging above the main valley. It will become a waterfall.

Question 13

What is a ribbon lake?

Answer 13

They are lakes formed after meltwater is deposited in areas of soft rock that the glacier eroded easily.

Question 14

Name four types of moraine.

Answer 14

Lateral, terminal, ground, medial.

Question 15

Define lateral moraine.

Answer 15

Material derived from freeze-thaw weathering of valley sides and which is carried at the sides of a glacier.

Question 16

Define medial moraine.

Answer 16

Found in the centre of a glacier and results from two lateral moraines joining together.

Question 17

Define terminal moraine.

Answer 17

Material deposited at the snout of a glacier. If a glacier remains stationary for a long time, then a sizeable mound of material can build up.

Question 18

Define ground moraine.

Answer 18

Material dragged underneath a glacier which, when deposited, forms the flat valley floor. Ground moraine is also referred to as til or boulder clay.

Question 19

What is an esker?

Answer 19

A glacier starts to melt. The meltwater collects into tunnels with sand and gravel. When the ice melts, a long, winding ridge is left.

Question 20

What is a kettlehole?

Answer 20

It forms when a block of ice is buried beneath moraine. When the ice thaws, a depression forms! They can be very big.

Question 21

What is an erratic?

Answer 21

Rocks and boulders carried by ice and deposited in an area of totally different rock.

Question 22

How are boulder clays formed?

Answer 22

Ice carries moraine beneath and on top of it. When the ice melts, it deposits the moraine. This forms a covering of soil, called boulder clay. It is clay soil with stones of different sizes in it.

Question 23

What are drumlins?

Answer 23

Smooth, rounded material. Consists of stone and clay. They result from the load carried by a glacier being deposited.

Question 24

What is outwash?

Answer 24

Meltwater streams run through moraine, picking up rock pieces. Streams drop these beyond the moraine as they slow down. Largest pieces are dropped first, then the smaller pieces. These areas of sand and gravel, rounded and sorted by the water, are called outwash plains.