P1 Glacial Landscapes Flashcards
How long does a quaternary period last?
2 million years
What are the two types of periods?
Glacial and interglacial periods
How long ago was the last ice age?
22,000 years ago
How thick was the ice in the last ice age?
3km thick
What is a glacial period?
When global temperatures drop to an average below 15C. When glaciers can build up into big ice sheets which cover mountain ranges and move to lowland areas.
What is an interglacial period?
A period of time when temperatures around the world are above 15C for extended periods of time
What evidence do we have for the last ice age in the uk?
.steep sided mountains
.shore lines on mountains formed by glaciers
.erratics
.loch ness - the depth gets very deep very quickly
-drumlins
What caused the last ice age in the uk?
Orbital cycles of the earth around the sun, changes every 100,000 years
What is a glacier?
A thick moving mass of ice that usually forms in mountainous areas and moved downhill causing the processes erosion, deposition,and transportation.
Describe the process of freeze thaw-weathering
.water seeps into cracks in the rock face
.temperature falls at night causing the water to freeze
. Water expands 10% when it freezes
.the water melts again and seeps further into the crack and the process repeats until eventually the rock face cracks
What is glacial erosion?
The wearing a way and removal of the land by flowing water, ice or wind
What are the two main erosional processes?
Plucking and abrasion
What is plucking?
When a glacier moves over an area of rock and due to friction, the glacier melts ad water seeps into cracks around the rocks below. The water re freezes and the rock effectively becomes a part of the glacier nd is ripped out when the glacier continues to ove forward.
What is abrasion?
Where rocks at the bottom of the glacier act like sandpaper grinding over the bedrock. This can polish the rocks or create sharp grooves called striations.
What is glacial transport?
As glaciers move they transport debris(till) along with them in various ways.
What three ways is till carried with a glacier?
.subglacial material : plucking/abrasion , underneath or inside the ife
.englacial material: material that has fallen into crevices (cracks in the ice)
.supraglacial material: material that has fallen onto the ice
What does glacial till form when in it deposited?
Moraine
What is bulldozing?
When a glacier moves forward it can avt like a giant earth wormer bulldozing piles of rock and debris in front of it to create a high ridge called moraine.
Why do glaciers deposit material?
Because they loose energy
What is a Corrie?
A bowl shaped hollow with a steep back wall and ridges, forming an armchair around the hollow, sometimes containing a small round lake called a tarn
How is a Corrie formed?
- snow accumulates in a depression or in a hollow high up in a mountain area
- over time the snow compresses into ice which then starts moving
- plucking occurs on the back wall of the glacier making it steeper
- freeze-thaw weathering occurs which produces scree which then gets trapped in the ice
- the mass slides downhill, scree in the glacier causes abrasion scrapes away the floor, making it deeper
- there is less arrosions at the front of the glacier which causes a rock lip to form as a result of less powerful erosion.
- when all the ice has melted a tarn forms
What is an arête?
Two back to back corries with steep sides forming an arête
What is a pyramidal peak?
When three or more corries grow in hollows on all sides of a mountain.
How does a ribbon lake form?
.glacier find it difficult to erode hard rock
.glacier easily erodes the softer rock forming a rock basin
.the ribbon lake is dammed by a rock bar (of harder rock)
.marraine may be deposited by the glacier which will also dam the lake
How do glacial troughs (u-shaped valleys) form?
-As the glacier moves down the valley it plucks the rock from beneath
-those rocks then rub against the base of the valley, eroding it further
-This deepens and widens the valley
-At the front end of the glacier it acts ike a bulldozer,shifting and removing soil, plucking rock from interlocking spurs and truncating them
- This creates truncated spurs.
How do truncated spurs form?
.glaciers bulldoze interlocking spurs and truncate them
How do hanging valleys form?
- Within glacial valleys there are main glaciers and smaller tributary glaciers
- the main glacier can erode its valley to a much greater extent because they are wider, deeper, have more mass and more moraines to use as erosive tools.
- The tributary valley glaciers are smaller, have less mass and morain and hence erode the valley less
- This means the main valley is wider deeper and steeper and a tributary glacial valley is left hanging above the main valley.
What is a drumlin?
A hill made of glacial till deposited by a moving glacier, usually elongated or oval in shape, with the longer axis parallel to the former direction of ice
What are erratics?
Rocks which have been transported and deposited by a glacier some distance from their source region
What is moraine?
Frost-shattered rock debris and material eroded from the valley floor nd sides, transported and deposited by glaciers.
How are drumlins formed?
.first material is deposited underneath a glacier as ground moraine
.second, this ground moraine is sculpted to form drumlin shapes by further ice movements
Name the 5 different types of moraine
.Ground
.terminal
.lateral
.medial
.recessional
What is ground moraine?
Moraine spread all over the ground as a glacier retreats up a valley in warmer times
What is terminal moraine?
Rocks deposited in a ridge at the maximum advance of the ice
What is lateral moraine?
Ridges of moraine that come from the valley sides and run parallel to those valleys sides
What is medial moraine
Ridges of rock running down the middle of a valley formed by two lateral moraines from two glaciers coming together
What is recessional moraine?
- often run parallel to terminal marines
-these ridges of material mark the retreat of a glacier.
-Each recessional moraine marks a point where the ice has been static for long enough in the glaciers retreat for material to build up.
What landforms are there in an upland area in the uk affected by glaciation?
.erratics: bowder stone
.arêtes: striding edge
.Corrie: Red tarn
.moraines: easedale valley
Glacial trough: language valley
.drumlins: Kendal
What 4 economic activities take place in glaciated upland areas?
.tourism
.faming
.forestry
.quarrying
How many jobs does tourism provide in the Lake District?
18,000
How many tourists are there per year in the Lake District?
18million per year
What % of houses in the Lake District are holiday homes?
15
How much do tourists spend per year on average in the Lake District?
1.2 million
What type of farming occurs in glaciated upland areas?
Hill sheep farming (high rainfall,steep hills, acidic soil, low temperatures so cant grow crops)
Why is forestry an opportunity in glaciated upland areas?
Coniferous trees grow fast and aren’t too good for habitats
What is quarrying?
The process of removing rock, sand, gravel or other minerals from the ground.
What tourism opportunities do upland areas(affected by glaciation) offer
Hiking,cycling,climbing and nature watching
Land use conflicts in glaciated upland areas
-farming and tourism(leaving gates open and littering)
-quarrying and conservation(quarry’s are damaging to natural environment and are unattractive,lorries on narrow country can cause damage to verges and create air pollution)
-tourism and conservation(excessive tourism can lead to air pollution from vehicles,litter and footpath erosion.
Lake District tourist attractions
-Water sports(lake Windermere)
-rock climbing and a sailing
-biking+hiking
-fishing
-off-road driving and quad biking
Social impacts of tourism
-congestion (on narrow winding roads can be a major issue)
-local people can’t afford to buy houses due to wealthy tourists buying second homes
-jobs tend to be seasonal and poorly paid
-better public transport
Environmental impacts of tourism
-can create air pollution(by vehicles)
-litter
-footpath erosion
Economic impacts of tourism
-more job opportunities
-local businesses thrive
Explain two strategies that manage the impacts of tourism
Traffic can be managed by-public transport encouraged by having specific bus routes for bikers and hikers;traffic calming in villages
Footpath erosion can be managed by-volunteer groups and organisations such as ‘fix the fells’ work with land owners to restore and repair footpaths using local stone and sheep wool to make them more resilient;replanting of native plants and those able to withstand trampling reduces erosion;signs implemented to encourage people not to stray off dedicated footpaths
