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Geography > Glaciation > Flashcards

Glaciation Flashcards

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1
Q

What is carbon dating?

A

Using radioactive testing to find the age of rocks which contained living material

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2
Q

What is erosion?

A

The wearing away of a landscape

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3
Q

What is an eon?

A

A basic unit of geological time in which a single type of rock system is formed

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4
Q

What is an epoch?

A

A subdivision of the geologic timescale that is longer than an age and shorter than a period

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5
Q

What is geology?

A

An earth science comprising the study of solid earth, the rocks it is made up of and the processes by which they change

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6
Q

What is glaciation?

A

A cold period of time when the earth’s glaciers expanded widely

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7
Q

What is strata?

A

Horizontal layers of rock

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8
Q

What was snowball earth?

A

A deep freeze around 715 million years ago which lasted around 120 million years

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9
Q

What are the Milankovich cycles?

A

-Eccentricity = elliptical orbits mean the earth is either very far from or close to the sun causing melting periods, this changes every 100,000 years
-Wobble = wobbles to create a circular orbit every 21,000 years causing mild winters and cooler summers
-Tilt = changes its axis from 21.5 to 24.5 degrees every 41,000 years which can cause much hotter summers and much colder winters

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10
Q

What are solar variations?

A

They are sunspots on the earth’s surface showing that the sun is more active that usual, if there are more emissions it can increase the earth’s average temperature

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11
Q

What are volcanic eruptions?

A

They release ash and sulphur dioxide gas and when they reach the atmosphere they reflect solar energy and prevent it reaching earth

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12
Q

What are meteorological processes?

A

Determines why some areas have ice cover
-polar glacial dry low temperatures
-low precipitation due to high pressure
-alpine areas

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13
Q

What is the cryosphere?

A

Part of the earth’s crust and atmosphere that are subject to temperatures below 0 degrees for at least part of the year
e.g ice sheets or glaciers

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14
Q

What is the hydrological cycle?

A

The movement, transfer and storage of water around the world

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15
Q

How does ice affect the hydrological cycle?

A

Maintains a freshwater store

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16
Q

Why is the cryosphere important?

A

-Provides habitat
-Large freshwater supply
-Allows for research purposes
-Affects sea levels and currents

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17
Q

What ways can we classify different ice masses?

A

-Thermal characteristics = whether it is warm or cold based
-Morphology of the land = studying the characteristics, origin and development of the landforms
-Degree of constraints = is the glacier hemmed in by valleys or not

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18
Q

What is a warm based (temperate) glacier?

A

-Water is present throughout the ice mass and acts as a lubricant
-This allows greater rates of movement and erosion
-They are often found at mountain glaciers at lower latitudes and higher altitudes

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19
Q

What is a cold based (polar) glacier?

A

-They occur in high latitudes where snowfall is below 0 degrees and the glacier is 0 degrees all year
-The glaciers stay frozen all year so there is little ice movement and little erosion

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20
Q

What is a cirque glacier?

A

Small and occupy armchair shaped hollows on mountains and can over spill to feed valley glaciers

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21
Q

What is a piedmont glacier?

A

A valley glacier which extends beyond the end of a mountain valley into a flatter area and spreads out

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22
Q

What does periglacial mean?

A

Areas at the edge of permanent ice characterised by permafrost and tundra environments

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23
Q

What is permafrost?

A

Where a layer of soil, sediment or rock below the surface remains permanently frozen
-it can reach depth of 400 to 500 metres
-e.g Russia, Greenland, Canada

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24
Q

What is an active layer?

A

The top soil in permafrost environments that thaws during summer and freezes during the winter

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25
Q

What are the three types of permafrost?

A

-Continuous = in the coldest regions with little thawing in the summer
-Discontinuous = slightly warmer and doesn’t penetrate as deeply
-Sporadic = temperatures are around freezing and it happens when the climate is cold enough to prevent thawing in the summer

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26
Q

Which factors influence the distribution of permafrost?

A

-Climate = determines the depth and extent of the permafrost
-Vegetation cover = prevents sunlight reaching the ground
-Snow cover = reflects sunlight so no sun reaches the ground

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27
Q

What is mass balance?

A

The net gain or loss of ice in a glacier over a specific period

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28
Q

What is dynamic equilibrium?

A

When outputs and inputs are balanced

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29
Q

What is sublimation?

A

The transition of a substance directly from the solid state to the gas state without passing through the liquid state

30
Q

What is internal deformation?

A

-Inter granular movement moves the individual ice crystals over each other
-This causes the ice crystals to become deformed or fractured due to stress within the ice
-The ice movement can then form crevasses
-Happens in warm and cold based glaciers

30
Q

What is accumulation?

A

Any process increasing the mass of the glacier

30
Q

What are feedback loops?

A

Deviations in inputs or outputs that move systems away from their equilibrium

30
Q

How does ice form?

A

-Snowflakes fall and accumulate, this is made of loose snow which is 90% air
-The ice compacts and the flakes undergo pressure, this causes granular snow which is 50% air
-This continual compaction produces firn forming glacial ice with trapped air making it blue, this made of firm snow which is 25% air

31
Q

What is a crevasse?

A

A deep v-shaped cleft formed in the upper part of a glacier as a result of the ice undergoing extension

31
Q

What is ablation?

A

Any process that decreases the mass of the glacier

31
Q

What is negative feedback?

A

Regulates systems to maintain the balance and equilibrium

31
Q

What is positive feedback?

A

Enhances and speeds up the processes promoting rapid change

31
Q

What is basal slip?

A

-Meltwater acts as a lubricant reducing friction with the bedrock and debris
-Happens in warm based glaciers
-Is accountable for 75% of warm based glacier movement

32
Q

What is plucking?

A

A form of erosion which pulls away pieces of rock as the glacier moves

33
Q

What is a macro-scale landform?

A

Large scale landforms that have been created by a combination of glacial processes over a period of time
e.g cirques, aretes

34
Q

What is a meso-scale landform?

A

An intermediate scale landform that has been created mostly by erosion and meltwater erosion
e.g drumlins, roche moutonees

35
Q

What is a micro-scale landform?

A

Small scale landforms
e.g striations, erratic

36
Q

What does sub glacially mean?

A

Moving material to the base and sides, happens mostly in meltwater

37
Q

What does en glacially mean?

A

Moving material within the glacial ice

38
Q

What does supra glacially mean?

A

Transporting material on top of the ice

39
Q

How does a glacial trough form?

A

Glacial troughs are U-shaped valleys carved out by the erosive action of glaciers

40
Q

How does a hanging valley form?

A

Form when smaller glaciers in the tributary valleys are unable to erode as deeply as the larger, main glacier

41
Q

How does a truncated spur form?

A

There are ridges which were cut off by the erosive action of the glacier

42
Q

How does an arete form?

A

Narrow ridges forming between two adjacent glacial valleys due to erosive actions of glaciers on both sides of the mountain ridge

43
Q

What is a pyramidal peak?

A

Pointed, steep-sided mountains with three or more faces forming at the intersection of multiple areas due to glacial erosion on the mountain

44
Q

What is till?

A

Mixed or unstratified material deposited by the ice

45
Q

What is lodgement till?

A

Occurs beneath the ice mass when friction between the debris and the bed gets stuck and the glacier moves past it
-results in more rounded and smooth till due to abrasion

46
Q

What is ablation till?

A

Debris dumped as the glacier melts and thaws
-results in more angular rocks as they do not experience abrasion

47
Q

What is terminal moraine?

A

Where the front of the glacier was, shows the furthest the glacier travelled

48
Q

What is recessional moraine?

A

The point the glaciers snout reached before the glacier started to retreat

49
Q

What is an erratic?

A

Boulders transported and deposited by a glacier

50
Q

What is a moulin?

A

A circular, vertical, well-like shaft within a glacier trough which water enters from the surface, it carries meltwater from the surface down to wherever it may go

51
Q

What makes Antarctica special?

A

-Remote continent on earth
-Coldest, windiest, least populated
-Smallest continent except from Oceania
-Gigantic ice sheet
-Coldest temperature recorded was -89.2 degrees

52
Q

What are the economic values of glacial environments?

A

-Farming = provides high slopes, high precipitation, low temperatures where sheep can be moved in the summer allowing the grass to recover e.g in the UK
-Forestry = involves researching tree types to understand different plant species
-Mining and quarrying = there are oil and gas stores in the rock beneath the ice sheet e.g the Antarctic
-Hydroelectricity = created by increasing the pressure of water flow through a turbine producing electricity e.g Switzerland
-Tourism e.g the Swiss Alps

53
Q

What is polar tourism?

A

-Started around 170 years ago
-1991/92 had around 64,000 visitors
-74,000 passengers visited in 2019/20
-There were 8x as many operators before the pandemic than there were in 1991/92
-60 ships and 408 cruises which travel there

54
Q

How does an avalanche happen?

A

A grinding motion starts and rapidly accelerates on slopes of more than 30 degrees

55
Q

What are lahars?

A

-The most destructive volcanic events
-They are a mixture of water, volcanic ash, tephra, rock fragments and chunks of ice
-1985 eruption in Columbia

56
Q

What is geomorphology?

A

The study of the physical features of the surface of the earth and their relation to its geological structures

57
Q

What is uniformitarianism?

A

A concept which suggests that catastrophic (biblical) processes were not responsible for the landforms that exist on earth’s surface
-it was developed by James Hutton in 1785
-suggests that supernatural theories were not needed to explain the geological history of the earth

58
Q

What is a polycyclic landscape?

A

A concept that most glacial regions are produced by a series of glaciated periods in one area

59
Q

What is a corrie?

A

A round hollow in the side of a hill

60
Q

What is a pingo?

A

A mound produced as ground is forced upwards through frost heave

61
Q

What is frost heave?

A

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

62
Q

What is a roches moutonnees?

A

A rock shaped by the glacier flowing over it and eroding it

63
Q

What is basal sliding?

A

Glaciers sliding over bedrock due to meltwater between the two surfaces

64
Q

What is a drumlin?

A

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

Geography (11 decks)

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