Land and Water, Glaciated Landscapes

Question 1

What can be inferred by New Zealand’s abundance of valleys?

Answer 1

That, unlike Australia, it was a highly glaciated landscape

Question 2

Glacier

Answer 2

A large mass of perenial ice resting on land or adjacent to it. Moves downslope due to their weight and gravity

Question 3

Firn

Answer 3

Compacted snow

Question 4

How is the accumulation zone of glaciers linked to their movement?

Answer 4

The accumulation zone is the build up of snow/ice at the source. As this ice/snow thickens, its mass increases, causing flow to occur

Question 5

What are the two types of flow?

Answer 5

1. Basal slip
2. Plastic flow

Question 6

Basil slip

Answer 6

The melting of ice/snow on the ground due the combined effect of temperature and pressure. Water reduces friction, allowing it to slide

Question 7

Plastic

Answer 7

The internal deformation of ice

Question 8

Ablation zone

Answer 8

The melting zone of snow/ice at the downstream margin. This zone melts faster than the accumulation zone, making the glacier appear to move upwards

Question 9

When was the last glacial maximum?

Answer 9

18,000 years ago during the Pleistocene when ice sheets and glaciers covered 30% (now 11%) of Earth’s land area

Question 10

Where do glaciers form?

Answer 10

In places of high latitude and/or altitude

Question 11

What are the two theories of glacier formation?

Answer 11

1. Plate tetctonics
2. Milankovitch cycles

Question 12

Plate tectonics of glacier formation

Answer 12

In the continent of Pangea 300 million years ago, there were higher latitude location. The moving land mass would have changed ocean currents, subsequently changing climate

Question 13

Milankovitch cycles of glacier formation

Answer 13

Periodic variations in Earth’s orbit which reduced the intensity of solar radiation, allowing glaciers to form/expand

Question 14

What two erosional processes are carried out by glaciers?

Answer 14

1. Abrasion
2. Plucking

Question 15

Abrasion

Answer 15

Glaciers scraping against the surrounding environment

Question 16

Plucking

Answer 16

Glaciers picking up and freezing eroded sediment

Question 17

What two landforms are charcateristic of past glacial environments?

Answer 17

1. Smooth surfaces (glacial polish once glacier retreats)
2. Striations from abraded material chiseling the surrounding environment

Question 18

What type of sediment is produced by glaciers?

Answer 18

Glacial flour: Very fine grained sediment that is constantly worked upon by fluvial and aeolian processes

Question 19

What type of valleys are prduced by fluvial and glacial processes?

Answer 19

Fluvial: V-shaped valleys
Glacial: U-shaped valleys

Question 20

What is the gernal term for glacial deposits and its two subtype?

Answer 20

General term: Drift

1. Till
2. Straified drift

Question 21

Till

Answer 21

Unsorted and unstratified sediment deposited directly from melting ice

Question 22

Stratified drift

Answer 22

Sorted and bedded deposits from fluvial processes or other weathering or erosional processes

Question 23

What are the three types of moraines?

Answer 23

1. Lateral (start/edges)
2. Medial (middle/meeting point)
3. Terminal (end/foot)

Question 24

What are the three main post-glacial features?

Answer 24

1. Drumlins
2. Outwash plains
3. Loess deposits

Question 25

Drumlins

Answer 25

Oval, elongated hills shaped by the streamlined movement of glaciers

Question 26

Outwash plains

Answer 26

Flat, expansive areas dominated by braided rivers due to the active melting of glaciers

Question 27

Loess deposits

Answer 27

Fine-grained sediment that is blown vast distances to prduce fertile plains

Question 28

What climate is needed for periglacial geomorphology?

Answer 28

Cold climates that allow glaciers to form temporarily, causing the the ground to permafrost

Question 29

What is the active layer of periglacial environments?

Answer 29

The zone of seasonally frozen ground between the subsurface and permafrost layer. This layer experiences constant freeze-thaw cycles

Question 30

What are the two freeze processes?

Answer 30

1. Frost heave
2. Freeze-thaw

Question 31

Frost heave

Answer 31

The vertical and horizontal movement of particles that are in the process of freezing

Question 32

Freeze-thaw

Answer 32

The repititive melting and freezing of ice. The expansion of water due to freezing causes rocks to fracture. Produces very distinctive patterns on the ground

Question 33

Eustacy

Answer 33

The rise and fall of sea level due to changes in water quantity. Also occurs due to changes in the shape and capacity of basins

Question 34

Isostasy

Answer 34

The rise or fall in land due to changes in elevation of the Earth’s crust. This changes relative sea level

Question 35

Glacio-isostasy

Answer 35

The regional/local rise or fall of land caused by the melting or expansion of ice sheets. This can cover new coastlines or reveal older, drowned coastlines