Glacial Landscapes

Question 1

What is a glacier?

Answer 1

A large accumulation of snow and ice which moves under its own weight.

Question 2

How does a glacier form?

Answer 2

Precipitation falls as snow.

Each Layer becomes heavier and compresses the layers underneath.

This is called diagenesis

Real glacial ice is when there is only 20% of air as bubbles

Question 3

What is an open system?

Answer 3

A system that allows the transfer of both matter and energy to neighbouring systems

Question 4

What is a glacial period

Answer 4

Periods of very cold and dry climate in which land ice and valley glaciers have grown to their maximum levels
The last one ended 10,000 years ago

Question 5

What is an interglacial period

Answer 5

Warmer periods during which much of the ice has retreated
Current interglacial period is known as the Holocene

Question 6

Inputs of a glacial system

Answer 6

Snow, hail, avalanches, rock debris, solar energy

Question 7

Outputs of a glacial system

Answer 7

Calving, melting, sublimation, evaporation, previously eroded material that has been transported and deposited by the glacier

Question 8

Give an example of a positive feedback loop in a glacial environment

Answer 8

Temperature rises - Permafrost melts - Co2 released - Greenhouse effect - Temp rises

Question 9

Give an example of a negative feedback loop in a glacial environment

Answer 9

Temp rises - Permafrost melts - Plants absorb more co2 - Reduces greenhouse effect - Temp cools

Question 10

Name the 4 types of polar environments

Answer 10

Polar, Periglacial/tundra, alpine, glacial

Question 11

What is the albedo effect

Answer 11

When incoming solar radiation is reflected back into space due to light colours such as ice
This causes it to be cooler in these areas

Question 12

Outline the characteristics of the climate in periglacial environments

Answer 12

Very cold and dry all year round
little seasonality

Question 13

What are the main features of soil in periglacial environments?

Answer 13

Lack of clearly defined layers

Thin organic layer, often acidic

Waterlogged in summer

Question 14

What are the main features of vegetation in periglacial environments?

Answer 14

Low level of production

Low levels of biodiversity

Vegetation close to the ground

Question 15

What does aspect mean?

Answer 15

The direction the slope faces

Question 16

What does accumulation mean

Answer 16

The addition of snow and ice over time

Question 17

What does ablation mean?

Answer 17

The loss of snow and ice overtime

Question 18

What is the net balance of a glacier

Answer 18

The difference between accumulation and ablation

Question 19

What is pressure melting point

Answer 19

That temperature at which ice is on the verge of melting

Question 20

Outline the characteristics of a warm based glacier

Answer 20

Found at high altitude locations

Meltwater means the glacier is more mobile

More rates of erosion, transportation and deposition

Athabasca Glacier

Question 21

Outline the characteristics of a cold based glacier

Answer 21

Found at high latitude locations

Less meltwater so often does not move much

Much less erosion, transportation and deposition

Meserve Glacier

Question 22

Outline the process of internal deformation

Answer 22

Explains the movement of cold based glaciers
Under great pressure at the base of a glacier the ice crystals allign themselves to the direction of movement of the glacier
Most likely near the bed as pressures are highest
Cracks can emerge leading to the formation of crevasses
Glacier remains frozen to the bedrock

Question 23

Corries

Answer 23

Form when snow continues to build up in a nivation hollow and eventually compacts to form a glacier

Glacier becomes trapped within the hollow, only way it can move is rotational slip

Back wall eroded through plucking and frost shattering, hollow deeped via abtasion

Water can fill corries to make tarns

Question 24

Arêtes

Answer 24

A knife edged ridge formed between two corries (when two steep backwalls meet)

If three meet they create a pyrmaidal peak

Question 25

Glacial Troughs

Answer 25

A u-shaped valley formed by a glacier bulldozing and eroding through a river valley

The glacier has enough force to erode a rivers interlocking spurs leaving smooth but steep truncated spurs

aswell as a wide flat valley floor

The original river will continue to flow but now as a misfit stream due to the difference in its size with its surroundings

Question 26

Hanging Valleys

Answer 26

A smaller u-shaped valley caused by a tributary glacier. The smaller glacier does not have enough energy to erode to the valley floor leaving a hanging valley where waterfalls usually form

Question 27

Roche mountonees

Answer 27

Glacier hits an obstacle that is too large/hard to pluck
Hitting the obstacle creates pressure and friction increasing melting as the lower ice reaches PMP
The meltwater allows the glacier to slide over the rock and smaller rocks abrade the stoss side
When the glacier reaches the top of the obstacle friction and pressure drop
Meltwater refreezes
Frozen rocks are plucked from the lee side

Question 28

Till plains

Answer 28

Unsorted glacial material formed through erosion and weathering

Form when an ice sheet detaches from the main glacier and melts causing all of the till on top of and within the glacier to deposit on the valley floor

Question 29

Erratics

Answer 29

A large boulder that is of a different rock type to the surrounding rock
Would have been broken off by weathering and erosion then transported by a glacier and deposited when it has been moved to a different location

Question 30

Moraines

Answer 30

Deposits of eroded material that are transported with the glacier

Lateral: Material deposited on the sides of a glacier leaving a ridge when the ice melts

Medial: Formed when two lateral morains meet in the middle of a glacier and deposit material

Ground: Carried under the glacier and abraded between glacier and valley floor. Only sorted moraine

Recessional: Forms at the end of a glacier

Question 31

Drumlins

Answer 31

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

The glacier moves over the large mound and drags excess deposition to the other side
Tear drops shape with a long tapered edge

Blunt end - stoss side

Tapered end - Lee side

Question 32

Why is plant growth difficult in the Tundra?

Answer 32

Waterlogged soils - thawed soils can’t infiltrate through permafrost and evaporation rates are low
Strong winds
Low levels of precipitation
Low insulation
Short growing season - no more than 60 days

Question 33

Vegetation and soil characteristics in cold environments - polar

Answer 33

Slow nutrient cycles
Climate means decomposers can’t thrive
Cold, harsh climate with little rainfall - only highly adapted vegetation can grow such as mosses and lichen
Overall there is a cycle where poor vegetation creates poor soil and poor soil causes poor vegetation

Question 34

Vegetation and soil characteristics in cold environments - Alpine

Answer 34

Heavy snowfall in winter
In summer there is heavy rainfall aswell meltwater
Mild temps stimulate plant growth, thawing and decomposition

Alpine vegetation is decomposed more quickly than in a polar climate, and grows quicker too due to soil fertility and climate.

The nutrient rich vegetation allows a more fertile soil to develop when it decomposes, as the nutrients are transferred into the soil. This fertile soil allows more nutrient rich plants to grow.

Question 35

Vegetation and soil in cold environments - periglacial tundra

Answer 35

Temperatures are consistently below freezing.

The latitude of some permafrost regions also assists in the consistently cold temperatures, as winters in higher latitudes last longer with less daylight hours, making them colder.

Vegetation is more prevalent than in polar regions, but only highly adapted plants can survive in the cold temperatures with little rainfall.

The temperatures and poor soil leads to a slow nutrient cycle. The lack of nutrient rich plants contributes to the soil infertility.

The cold climate causes the lower ground to be frozen all year around. However, slightly warmer summer temperatures cause the thawing of upper soil called the active layer. Soil is usually extremely waterlogged in summer due to thawing, which means plants become deoxygenated within the soil and cannot survive, and any nutrients are often leached out.

Question 36

Vegetation adaptions to tundra environment

Answer 36

Vegetation grows close to ground - protects from strong winds
Shallow roots - To allow it to get nutrients from the active layer
Can photosynthesise at low temps - due to low temps from albedo effect, they can create energy
Perennial plants - store food to allow them to survive during harsh winters