1
Q
What does glacial mean?
A
a cooler interval of time during thousands of years of an ice age when a glacier advances
2
Q
What does interglacial mean?
A
a warmer interval of time during the long time span of an ice age , when a glacier retreats
3
Q
What are the 2 eras?
A
cenozoic, mesosoic
4
Q
During the quaternary period, what epochs occurred?
A
holocene, Pleistocene
5
Q
What were the 2 divisions within the late holocene?
A
devensian
ipswichian
6
Q
What were the 4 divisions within the middle holocene?
A
wolstonian, hoxnian, Anglian, cromerian
7
Q
How old is the earth?
A
4.6 billion years old
8
Q
What does stadial mean?
A
colder climate that occurs during an interglacial period or within an overall warmer period
9
Q
What does interstadial mean?
A
warmer climatic period that occurs within a larger, colder glacial phase
10
Q
What are the 3 milankovitch cycles?
A
- changes in eccentricity of the orbit
2.changes in obliquity - precession of the equinoxes
11
Q
What is positive feedback cycle that relates to the albedo effect?
A
The melting of snow/ ice cover by carbon dioxide emissions decreases albedo, methane is emitted as permafrost melts, and warming seas lead to calving of ice sheets, which all lead to loss of snow/ ice cover and of surface albedo, decreasing reflectivity and acceleration further warming.
12
Q
What are the three milankovitch cycles?
A
- eccentricity
- changes in obliquity
- precession of the equinoxes
13
Q
What does the changes in eccentricity of the orbit mean?
A
the earths orbit around the sun can change from more circular to more oval shaped over a long period of time
14
Q
What does changes in obliquity mean?
A
how tilted the earth is (between 21.5 and 24.5 degrees)
currently the earths tilt is 23.5 degrees
15
Q
What does precession of the equinoxes mean?
A
the slow wobble of the earths axis
16
Q
What was the name of the last glacial maximum?
A
Loch Lomond stadial
17
Q
What is the cryosphere?
A
the whole of the frozen part of earth
18
Q
What is an ice sheet?
A
complete submergence of regional topography, forms gently sloping dome of ice several km thick in centre
19
Q
What is an ice cap?
A
smaller version of ice sheet occupying upland areas, outlet glaciers
20
Q
What is an ice field?
A
ice covering an upland area, but not thick enough to bury topography
21
Q
What is a valley glacier?
A
glacier confined between valley walls
22
Q
What is a cirque glacier?
A
a smaller glacier occupying a hollow on the mountainside
23
Q
What is an ice shelf?
A
large area of floating glacier ice extending from the coast where several glaciers have reached the sea
24
Q
Is an ice sheet unconstrained or constrained?
A
unconstrained
25
Is an ice cap unconstrained or constrained?
unconstrained
26
Is an ice field unconstrained or constrained?
unconstrained
27
Is a valley glacier unconstrained or constrained?
constrained
28
Is a cirque glacier unconstrained or constrained?
constrained
29
Is an ice shelf constrained or unconstrained?
unconstrained
30
What are the 2 factors used to classify a glacier?
location
scale
31
Where do temperate glaciers occur?
in high altitude places
32
Where do polar glaciers occur?
at high latitudes
33
Define glacial.
a cooler interval of time during thousands of years in an ice age when a glacier advances
34
Define interglacial.
a warmer interval of time during the long time span of an ice age, when a glacier retreats
35
Define stadial.
colder climate that occurs during an interglacial
36
Define interstadial.
warmer climatic period that occurs within a larger, colder glacial phase
37
Define Ice- house conditions.
very cold glacial conditions
38
Define greenhouse conditions.
much warmer interglacial conditions
39
What is the pleistocene?
a period from 2 million years ago to 11,700 years ago, which included the most recent ice age
40
What is orbital forcing?
a mechanism that alters the global energy balance and forces the climate to change in response
41
What is calving?
the breaking up of chunks of ice at the glacier snout of ice sheet front to form icebergs as the glacier reaches a lake or ocean
42
Why is it colder at higher latitudes?
at higher latitudes the rays from the sun are more dispersed
43
What are the milankovitch cycles?
hint- name all 3
1. eccentricity
2. obliquity
3. precession of the equinoxes
44
What does obliquity refer to?
Obliquity refers to the earths axis of rotation
45
What degrees does the earths tilt vary between?
21.5 and 24.5 degrees
46
What is the current tilt of the earth?
23.5 degrees
47
What does precession of the equinoxes mean?
the earths wobble like a spinning top
48
What does eccentricity mean?
the eccentricity refers to the shape of the earths orbit- it can vary from being more circular to more oval
49
What is the name of the last glacial period?
the Loch Lomond stadia
50
What is the cryosphere?
the cryosphere refers to all of the frozen water on earth
51
What are the 2 things needed to classify an ice mass?
location and scale
52
What is an ice sheet?
- complete submergence of regional topography
- forms a gently sloping dome of ice several km thick in the centre
53
What is an ice cap?
- a smaller version of ice sheet
54
What is an ice field?
- ice covering an upland area, but not thick enough to bury regional topography.
55
What is a valley glacier?
A glacier confined between valley walls and terminating in a narrow tongue
56
What is a cirque glacier?
a smaller glacier occupying a hollow on the mountainside
57
What is an ice shelf?
Large area of floating glacier ice extending from the coast where several glaciers have reached the sea
58
Is an ice sheet constrained or unconstrained?
unconstrained
59
Is an ice cap constrained or unconstrained?
unconstrained
60
Is an ice field constrained or unconstrained?
unconstrained
61
Is a valley glacier constrained or unconstrained?
constrained
62
Is a cirque glacier constrained or unconstrained?
constrained
63
Is an ice shelf constrained or unconstrained?
unconstrained
64
What is an example of a big ice sheet?
the Greenland ice sheet
65
Where are ice sheets found?
high altitude
polar
66
Where are ice caps found?
high altitude
polar
67
Where are ice fields found?
high altitude
polar
68
Where are valley glaciers found?
high altitude
69
Where are cirque glaciers found?
high altitude
70
Where are ice shelves found?
polar regions
71
On a mountain in the N hemisphere, which side would likely support a glacier the best?
north
72
The ________ side of a mountain is usually the side which has the glacier because it allows for greater a________.
north, accumulation
73
Describe the steps that snow undergoes to get to glacial ice over time.
1. snow
2. granular ice
3. firn/ neve
4. glacial ice
74
What does ablation mean?
the glacier loses mass
75
What does accumulation mean?
the glacier gains mass
76
What is the very end of the glacier (at the front) called?
the snout
77
Name 1 input source to a glacier that isn't precipitation.
avalanches onto glacier
78
On the mer de glace, what can temperatures reach in the summer?
over 30 degrees
79
In the upper slopes of the mer de glace, the glacier moves __ metres per day.
2
80
What does a positive regime mean in terms of the glacier mass balance?
the glacier grows and snout advances
81
What does a negative regime mean in terms of the glacier mass balance?
glacier retreats and snout retreats
82
20,000 years ago, the height of the mer de glace was __km higher than currently.
1km higher
83
If the Greenland ice sheet melted, how many metres would it raise global sea levels?
7m
84
What is basal slip?
where the glacier slides of the ground because of a layer of meltwater, lubricating it
85
What is regelation creep?
ice melts under high pressure when it encounters an obstacle on the glacier bed and then refreezes when the pressure is reduced after passing the obstacle
86
What is internal deformation?
when the immense weight of the ice causes internal stress, making ice crystals slide past each other along planes
87
What does lithology mean?
the physical characteristics of the underlying bedrock and unconsolidated sediments
88
What is entrainment?
glaciers incorporate surface or subglacial sediment into the flowing ice mass as part of the erosion process
89
What does sub-glacial mean?
beneath the glacier
90
What does supra-glacial mean?
the surface of the glacier
91
What does en-glacial mean?
within the glacier
92
What does pro-glacial mean?
areas next to where sediment is deposited
93
What is basal slip?
when meltwater lubricates and reduces frictional stress which increases the movement of the glacier
94
What is regelation creep?
when ice occurs an obstacle and melts due to the pressure and as the water flows around the obstacle it refreezes and the pressure drops
95
The closer the temperature becomes to _________ _______, the greater the regelation creep rate.
melting point
96
The greater the weight of the glacier, the _______ the flow.
faster
97
What is internal deformation?
movement between or within individual grains of ice, including grains slipping over each other, melting and recrystallising
98
In which type of glaciers does internal deformation occur?
cold based glaciers
99
What happens to internal deformation 100ft beneath the surface of the glacier?
due to the weight and pressure, ice crystals become layered and the ice moves in a plastic- laminar flow
100
In what zone does internal plastic deformation occur?
In the zone of plastic flow
101
Why are there no crevasses at depth in a cold based glacier?
due to internal deformation the ice bends and doesn't crack
102
Towards the surface of the glacier, the ice is brittle.
What is this zone called?
What are the cracks formed called?
1. the zone of brittle flow
2. crevasses
103
How old is the glacial ice in the mer de glace?
200 years old
104
How fast is the ice on the mer de glace travelling in the upper slopes?
2m per day
105
How fast is the ice on the mer de glace travelling in the lower slopes?
50cm per day
106
What does macro mean?
large scale
107
What does meso mean?
medium scale
108
What does micro mean?
small scale
109
What is a misfit river?
a river that hasn't formed the landscape but still flows through the landscape
110
What is a tarn?
a small lake found in a corrie
111
What is a pyramidal peak?
a collection of 3 or more corries formed back to back
112
What is a bergschrund?
a crack between the rock or glacier by the back wall of the corrie
113
On what kind of slopes are corries usually formed on and why?
north west- less sunlight
means accumulation highest here and ablation lowest
114
When the ice becomes too big for the corrie what occurs now?
the corrie slips down the slope via rotational slippage
115
Give an example of a corrie in the Uk.
Helvellyn - Lake district
116
What is a bergschrund?
A crevasse in the ice by the back wall of a corrie
117
What is plucking?
A rotational movement of the glacier picking bits of rock of the bedrock
118
Give and example of a pyramidal peak.
The Matterhorn- Alps ( Switzerland)
119
Give and example of an arête in the UK.
Helvellyn- striding edge
Lake District
120
Give an example of a U - shaped valley.
Yosemite valley- USA
121
Give an example of a ribbon lake in the UK.
Lake Windermere
Lake District
122
How does a ribbon lake form?
Glacier erodes softer bedrock faster than harder as it passes over. This leaves channels in the valley. These channels fill with water and form ribbon lakes on the valley floor.
123
What is a recessional moraine?
A lower ridge of till parallel to the terminal moraine
124
What is a medial moraine?
A ridge of till deposited in the middle of the glacier ( parallel to the valley sides)
125
What is a lateral moraine?
A ridge of till deposited at the sides of the valley
126
What is a terminal moraine?
A high ridge of till extending across the valley at right angles to the valley sides
127
What is the shape of a drumlin field described as?
A basket of eggs topography
128
What is a till plain?
A large, flat plain of till in a lowland area/ also called ground moraine
129
What is lodgement and ablation till?
Deposits of angular, unsorted rock fragments containing erratics
130
What is an erratic?
A large piece of rock that had been transported and deposited by a glacier and does not match the geoglogy
131
What is the difference between lodgement and ablation till?
Lodgement- till is deposited by actively moving ice, forming landforms such as drumlins
Ablation- till is deposited by melting ice from stationary or retreating glaciers forming landforms such as terminal and recessional moraines.
132
What does assemblage mean in the context of glaciation?
A group of landforms, sediments, and geological features found together that indicate the presence and behaviour of past glacial activity.
133
What is the diagram called to identify cirque orientation?
Star / radar/ rose diagram
134
What are clasts?
Small rocks or stones deposited by the glacier
135
Give an example of a hanging valley.
Bridalveil fall
Yosemite USA
136
What is a Roche moutonee?
An asymmetrical hillock, sculpted by a passing glacier
137
Give an example ofa Roche moutonee.
Camel’s hump
Vermont USA
138
What are striations?
Long thin parallel scratches carved into exposed bedrock by the base of a moving glacier
139
Is the Lee side the steep side or the gentle side on a Roche moutonee?
The steep downstream side
140
Is the stoss the steep side or the gentle side on a Roche moutonee?
The gentle side ( upstream side)
141
Is a roche moutonne made of glacial till or bedrock?
part of the bedrock
142
Give an example of a Roche moutonee.
camels hump - Vermont USA
143
Give an example of a crag and tail.
Edinburgh castle and the royal mile (Scotland)
144
Is the crag of the crag and tail the stoss side or the lee?
the stoss
145
Is the tail side of the crag and tail the stoss or the lee?
the lee
146
In a crag and tail landform, the ________ rock p_________ the ______ resistant rock behind it and the glacier deposits sediments behind the obstacle.
resistant, protects, less
147
Where is the only known active drumlin field located?
Iceland
148
What does the lochan an of the knock and lochan refer to?
the small lake formed behind the rock (knock)
149
Where can you find examples of knock and lochans?
northwest highlands
scotland
150
What is the topography of a field of drumlins described as?
a basket of eggs topography
151
On a drumlin, what is the gentle sloping side called?
the lee side
152
On a drumlin, what is the steep side called?
the stoss end
153
What are drumlins made of?
glacial till
154
Explain the formation of ribbon lakes.
1. glaciers erode less resistant rock more deeply than surrounding harder rock
2. overdeepening by ice traps meltwater and forms a lake
3. once the glacier melts and retreats, water from melted ice and rainfall fills the basin.
4. The harder rock bars or moraine deposits left at the glacier act asa dam, preventing the water from escaping and creating a long thin lake.
155
Explain how a hanging valley forms.
1. when a small tributary glacier joins a larger, more powerful main glacier, the main glacier erodes its valley deeper and wider due to higher ice volume, while the smaller glacier can't erode as deeply.
2. Post-glaciation, the tributary valley is left hanging high above the main U-shaped valley floor
156
Explain how a Roche moutonee forms.
1. as the glacier approaches a resistant rock outcrop, high pressure causes basal melting. 2. This allows the ice to glide over the rock, with embedded rocks acting like sandpaper to create striations on the bedrock.
3. as the ice passes over the crest, pressure decreases, causing meltwater to refreeze into cracks.
4. this freeze thaw process breaks the rock, allowing the moving glacier to pluck large rocks.
157
Explain how a crag and tail forms.
crag- a large resistant rock feature obstructs the advancing ice.
The ice is forced over and around this obstacle , causing erosion via plucking and abrasion, resulting in a steep, jagged, upstream face.
Tail- In the pressure shadow behind the crag, the ice velocity decreases, and the force of erosion s reduced. This protects the softer bedrock or allows the glacier to deposit sediment behind the obstacle.
158
Explain the formation of a knock and lochan.
1. abrasion and pluking smooth resistant rock into rounded hills (knocks) while deep erosion of weaker rocks creates hollows that fill with water. This creates a rugged, scoured, rocky terrain.
159
Explain the formation of a drumlin.
1. glaciers deposit sediment beneath the ice, which is shaped by pressure and movement.
2. the ice holds pre-existing material into an elongated shape.
3. high pressure causes wet sediment to deform, forming streamlined bedforms
4. as the glacier advances, it shapes the deposited till, creating a steep side where the ice hits and a gentle side where the ice tails off.
160
What is glacial till?
an unsorted mixture of unsatisfied sediment deposited directly by glaciers
161
What does supra glacial mean?
on top of the glacier
162
What does englacial mean?
within the glacier
163
What does sub- glacial mean?
underneath the glacier
164
What does fluvioglacial mean?
refers to erosion or deposition caused by meltwater from glacial ice
165
What does proglacial mean?
environments that are located at the front of the glacier, ice cap or ice sheet and dominated by fluvioglacial processes
166
Name the three ice contact fluvioglacial landforms.
- kames
- kame terraces
- eskers
167
Name the 4 proglacial fluvioglacial landforms.
1. outwash plains/sandhur
2. proglacial lake
3. kettlehole
4. meltwater channel
168
What two sources does meltwater come from?
surface melting
basal melting
169
Edexel Geography A- Level
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