Glacial landscapes Flashcards

1
Q

What is the relief of land

A

Refers to the highest and lowest elevation points in an area. Typically mountains and ridges.

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2
Q

What is topography?

A

The natural features of land especially the shape of its surface.

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3
Q

What is altitude?

A

Height above sea level measured in metres or feet

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4
Q

What is land use?

A

The purpose or function of land for example pasture, grassland, retail

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5
Q

What are lowland areas?

A

Lowland are close to or below 200m above sea level. One example is the Fens in East Anglia

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6
Q

What are upland areas?

A

Uplands are normally made up of mountains or high hills. Normally they are ares over 600m above sea level. Examples include the Cumbria mountains in the Lake District.

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7
Q

What is the highest point in the Uk?

A

Ben Nevis at 4406 feet (1343m) located in Scotland.

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8
Q

What are the 2 longest rivers in the Uk?

A

River Severn (south west Uk) and river thames (flows through London)

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9
Q

When was the last ice age

A

22,000 years ago

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10
Q

How thick was the ice the last ice age.

A

3km thick

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11
Q

What is a glacial period

A

When the temperature has dropped significantly low and ice advances

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12
Q

What is an interglacial period?

A

When the temperatures are warmer for an extended period of time

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13
Q

What processes were used by the ice sheet to shape the Uk?

A

Erosion, transportation, deposition etc

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14
Q

What is the ISO static rebound?

A

When ice melts, the land rebounds up

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15
Q

What are glacial erratics?

A

Boulders/large sediment that had been carried by the ice left in (random) high altitude areas.

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16
Q

Describe the formation of a glacier:

A
  1. Over a year, fallen snow is gradually compacted into ice
  2. because each year new layers of snow bury and compress previous layers
  3. The compression forces the snow to re-crystalize, forming sugar sized grains.
  4. Gradually the grains grow larger and the air pockets between the grains get smaller, causing the snow to slowly compacts and increase in density.
  5. After about 2 winters the snow turns in firn/neve - a middle state between snow and glacial ice
  6. For most glaciers this process takes more than 10l years.
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17
Q

Describe freeze- thaw weathering:

A

Water enters crack in rock, when it freezes it pushes rock apart, the ice melts and big gap is left.

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18
Q

What is plucking?

A

Where a glacier moves over an area of rock and due to friction the glacier melts and water seeps into cracks below. The water freezes and the rock effectively becomes part of the glacier and is ripped out when the glacier continues to move forward.

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19
Q

What is abrasion?

A

Abrasion is where rocks at the bottoms of the glacier act like sand paper - grinding over the bedrock. This can polish rocks or create sharp grooves called striations.

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20
Q

As glaciers move they transport debris (…………..) along with them in various ways

A

topsoil

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21
Q

subglacial material =

A

material plucked or abraded from bedrock beneath the glacier

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22
Q

englacial material

A

some material falls into crevasses and is transported inside the ice

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23
Q

supraglacial material

A

some material falls onto the ice from surrounding mountain sides so is carried on top

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24
Q

what is till made of

A

angular rocks/boulders

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24
sediment transported by ice is known as...
glacial till = can be deposited to form a morraine
25
what is sediment carried by meltwater rivers called
outwash = more rounded due to attrition by river erosion
26
front of glacier =
snout
26
what is basal sliding
Basal sliding is the act of a glacier sliding over the bed due to meltwater under the ice acting as a lubricant. This movement very much depends on the temperature of the area, the slope of the glacier, the bed roughness, the amount of meltwater from the glacier, and the glacier's size.
27
what is bulldozing
when a glacier moves forward it can act like a giant earthmover bulldozing piled of rock debris in front to create a high ridge called a moraine
28
why is there meltwater present under a glacier
the sheer weight of the ice above creates this great pressure = warms up ice (pressure melting)
28
how do glaciers move
As the weight of the ice accumulates gravity causes it to flow over the lip and down the mountainside The glacier slides over the underlying rock on a film of meltwater - basal flow As glacier moves down hill plucking and abrasion occur = large amounts of fragmented rocks are left= ground moraine When the ice flows into the lowland areas the climate is warmer and begins to melt so rock debris is deposited At the end, large amounts of meltwater pour off the snout of the glacier and carry debris far beyond there
29
what happens when ice looses energy
it drops materials
30
what is till composed of
unsorted mixture of material - boulder clay, clay pebbles Lodgement till spreads onto valley floor beneath the ice by moving glaciers
31
what is ablation till
till that is dropped as glacier melts
31
what does till show
direction glacier is flowing deposited as landforms called moraines
32
landform =
a naturally occurring feature on earth's surface caused by geographical processes e.g erosion
32
what is a corrie
A bowl shaped hollow with steep back wall and ridges, forming an arm chair shape around a hollow sometimes containing a small lake called a tarn
33
formation of corrie
Snow accumulates high up, predominantly on north facing slopes. Over time the snow becomes glacial ice and there is more ice than the depression can hold and some of it starts to flow to lower levels. Ice becomes frozen to the back of the hollow and plucking occurs as blocks of rock are pulled away as the ice moves downhill. This makes the back wall steeper and these rock fragments become incorporated into the glacier. Freeze thaw weathering occurs at the top of the slope producing scree which becomes incorporated into the glacier. When all the ice has melted a tarn (lake) forms. The hollow deepens where the ice is thickest due to abrasion. Rock debris acts as tools to wear away the bottom of the hollow. There is less erosion at the front where the glacier leaves the corrie hollow to flow down the valley; a rock lip forms here as a result of less powerful erosion.
34
aretes
a ridge formed by two back to back corries
35
pyramidal peaks are
formed when 3 or more corries grow in hollows on all sides of the mountain
36
where are the deepest corries found in uk
northeast side mountains where the least amount of sunlight is received
37
examples of arete in UK
Crib Goch in North Wales
38
what is glacial trough
the u shaped valley formed by abrasion and plucking of a glacier = V --> U valley shape
39
hanging valley
the portion of a valley that remains after a waterfall has fallen through it
40
where are truncated spurs found
along the sides of a glacial trough
41
how are truncated spurs/hanging valleys fomed
ice that spilt out of corries ice tributaries (glacial tributaries) left hanging valleys + ridges (truncated spurs)
42
Why do glaciers erode at different rates
Glacier finds it difficult to erode hard rock but easily erodes soft rock forming rock basin where ribbon lakes can occur - dammed by rock bar or deposited moraine
43
lateral moraine
a ridge of material which runs along the edges of a glacial trough close to the valley side. The source of this material is freeze-thaw weathering high on the valley sides causing shattered blocks of rock to form onto the glacier below which is deposited when the glacier melts/retreats
43
what are moraines
Produced by glacial erosion and deposition Accumulations of fallen rock debris from glacier with distinct shapes Different types form depending on where sediment has been placed
43
what are ribbon lakes
When some parts of valley floor are depended due to differential rates of erosion a ribbon lake is formed = long thin lakes that collect from melt water and rainwater in the u shaped valley the glacier has travelled through/melted in
44
medial moraine
when 2 lateral moraines merge together a large ridge of rock debris forms (thick dark stripe may run down middle of glacier below the point where 2 glacial tributaries have met)
45
terminal moraine
enormous ridge of material which gets bulldozed by the snout of a glacier. They allow us to work out how far the ice advanced during the last ice age
45
what are drumlins
egg shaped hills caused by glacial deposition group = swarm great ripples formed under ice = bums glaciers shape the material under the glacier = leaves drumlins
45
ground moraine
the material that gets lodged and deposited underneath the glacier - covers large uk areas
45
recessional moraine
these often run parallel to terminal moraine and these ridges of material mark the retreat of a glacier each recessional moraine marks a point where the glacier ice has been static long enough for material to build up when glacier retreats
46
why is the lake district a great example of a place with glacial andforms
Approximately two million years ago, the Lake District was a mountainous area with intersecting river valleys. Colder periods followed which led to ice ages. During these colder periods ice flowed out from the central core, following the river valleys, deepening and widening them, and depositing streamlined till and other depositional features on the lower land. This makes the Lake District a great example of a place with glacial landforms.
46
what do drumlins show
the direction the ice travelled 180 drumlins in glasgow
47
list of lake district glacial features
easedale tarn in lake district national park Greater langdale u shaped valley easedale valley - hanging valley milk ghyll water fall
47
what is rotational slip
Movement of the ice out of the corrie in a circular motion.
47
tourism
provides 1000s of jobs - shops, hotels, touring guides Hiking, cycling, climbing, nature watching
47
farming
Limited agricultural options in glaciated areas - soils tend to be thin/unfertile in mountains - soils can be waterlogged in valley bottoms -sloped are steep and often covered by scree and bare rock outcrops + hard to distribute water + nutrients evenly - harsh climate - high rainfall, low temps, snow however lots of sheep grazing (grass and hay stored for winter feeding) highland cattle + deer
48
economic activities in upland glaciated areas
tourism farming forestry quarrying
49
quarrying
upland glaciated areas made of tough rock = used for road building Lake district slate - blue/grey roofing and decorative material Pennines limestone used as landscaping material for gardens Highlands granite - tough, resistant, used for pavement edges
49
forestry
widespread conifer plantations = fast growing trees suited for harsh climate trees provide wood for construction and furniture some are chipped to use a biofuel
49
what is a honeypot site
a place of natural or human interest that attracts people in large numbers
49
Activities in Lake district
The world of beatrix potter attraction in windermere Lake district falconry in windermere private sailing experience in windermere mountain biking in ableside
49
impacts of tourism
in lake district there was a huge rise in property prices in summer but not winter = empty towns in winter - economic tourists disrupt farmers land - more people on foot path = erosion in land more tourists = traffic congestion = air pollution + less people work more littering - damaging to environment - habitats + wildlife