Geography - Physical landscapes: coasts and glaciers

Coastal and Glacial landscapes

swash

swash

the part of the wave that crashes onto the beach

backwash

the part of the wave sweeping back into the sea

fetch

the distance over water that the wind blows to create waves (longer fetch = more powerful wave

characteristics of constructive waves (7)

low wave height, long wave length, spilling wave, strong swash, weak backwash, low frequency, builds the beach by accumulating sediment

characteristics of destructive waves (7)

high wave height, short wave length, plunging wave, weak swash, strong backwash, high frequency, erodes the beach by removing sediment.

weathering

the wearing down or breaking of rocks in situ. can be biological, chemical or physical/mechanical.

types of weathering processes (3)

freeze thaw (mechanical), salt weathering (mechanical), carbonation (chemical)

mass movement

the movement of material downslope due to gravity, which can occur rapidly or slowly.

types of mass movement (4)

1. landslide (blocks of rock slide downhill)

2. rockfall (fragments of rock break away from cliff face)

3. mudflow (saturated soil + weak rock flow downhill)

4. rotational slip/slumping (curved movement of saturated earth material)

coastal erosion processes (4)

hydraulic action, abrasion, attrition, solution

types of transportation (4)

traction, saltation, suspension, solution

wave cut platform

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coastal erosion landforms (7)

wave cut platforms, bays, headlands, caves, arches, stacks, stumps

how are headlands and bays formed?

They form where there are alternating bands of resistant and less resistant rock along a (discordant) coastline.

Less resistant rock is eroded quickly and forms a bay, the resistant rock is eroded more slowly, leaving headlands jutting out.

coastal deposition landforms (4)

beaches, sand dunes, spits, bars

example of coastal landforms in the UK

swanage, Dorset

broad sandy beach in a sheltered bay on the Jurassic Coast

types of hard engineering (4)

1. sea wall (barrier between waves and land)

2. groynes (at a right angle to the sea)

3. gabions (smaller rocks in wire cages)

4. rock armour (huge boulders of hard rock as a barrier)

types of soft engineering (3)

1. beach nourishment (replacement of sand on a beach)

2. beach reprofiling (bulldozers move shingle back up the beach)

3. sand dune regeneration (artificial creation of new sand dunes/restoration of existing dunes

managed retreat and coastal realignment

a form of soft engineering where low-lying land is allowed to naturally flood so defences can be imroved further inland. coastal realignment is the alteration of the coastline.

aims of managed retreat (3)

1. improve coastal stability

2. protect inland areas rather than coast

3. create natural defences (eg salt marshes)

an example of a coastal management scheme in the UK

Lyme Regis (south coast of England)

details in my book!

longshore drift

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what and when was the last ice age?

during the Pleistocene, which began about 2 million years ago, ice covered over 30% of the Earth’s land surface (including nearly all of the UK)

what is the main glacial weathering process?

freeze-thaw weathering: water enters cracks, freezes and expands, and breaks segments of rock away (repetitive process).

glacial erosion processes (2)

1. abrasion (‘the sandpaper effect’): ice scours the valley floor, leaving a smooth, polished surface, sometimes with striations.

2. plucking: meltwater beneath the glacier freezes. as the glacier moves, loose fragments of rock are plucked away leaving a jagged rocky surface.

types of glacial movement (2)

1. basal slip: meltwater acts as a lubricant, enabling the glacier to move downhill. this can become quite sudden and occurs more often during summer months.

2. rotational slip: ice moves along a curved surface to enlarge and develop hollows.

bulldozing

material in a glacier is usually found at the snout. further movement of the glacier pushes this material downhill (this is called bulldozing).

hummock

a small mound of sediment which is formed by bulldozing.

how and where does glacial deposition occur?

when ice melts, meltwater pours off the snout of the glacier. this means that most deposition occurs at the snout.

glacial till

deposited material. it comprises a range of particle size and tends to be angular having had little water transportation.

outwash

(carried by meltwater streams) it tends to be more rounded than till and better sorted, with gradually finer material being deposited further away from the ice front.

glacial erosion landforms (7)

1. corries

2. arêtes

3. pyramidal peaks

4. hanging valleys

5. glacial troughs

6. ribbon lakes

7. truncated spurs

how does a corrie form?

(found in the upper course) snow and ice accumulates in a hollow in the mountainside. rotational slip by the glacier erodes the base of the hollow by abrasion and plucking, deepening the hollow. freeze-thaw weathering acts on the edge of the hollow creating deposits of scree and a steep back wall/sides. a rock lip forms at the front of the corrie due to reduced erosion where the ice is thinner. over time the glacier deepens the hollow, creating a corrie and meltwater may form a tarn.

arêtes

when 2 corries form back to back and erode towards each other, a ridge/arête is formed between them.

pyramidal peaks

when 3 or more corries develop on all sides of a mountain, the arêtes combine to form a peak.

hanging valleys

a tributary valley higher than the valley of the main glacier, formed from small tributary glaciers flowing towards the main one.

glacial troughs

before glaciation, the valley would have been v-shaped. during glaciation, the rock in the valley sides Is removed through plucking and abrasion. this results in a u-shaped valley with steep sides and a wide, flat floor.

ribbon lakes

formed on the base of a glacial trough, in areas of softer rock which have been eroded deeper. the meltwater sits in these depressions forming a long and narrow lake.

truncated spurs

as the glacier flows through a valley, its erosive power removes much of the valley sides, leaving blunt-ended sloping ridges.

a glacial deposition landform

drumlins: a small egg-shaped hill often found on the floor of a glacial trough. they are elongated features with a steep stops end, and the ice flow was towards the shallow lee end. they are formed when a glacier deposits moraine around an obstacle (eg a rock)

glacial transportation landforms (2)

1. erratics

2. moraines (5)

erratics

rocks which have been transported by ice and deposited elsewhere. this means that they are a different type of rock to the bedrock of the area they are in.t

types of moraine (5)

1. ground moraine: material dragged under the glacier

2. lateral moraine: forms on the side of a glacier (mostly scree from valley sides)

3. medial moraine: when two glaciers join, their lateral moraines merge into one which forms a ridge when the ice melts

4. terminal moraine: material that builds up at the end of the glacier. it marks the maximum extent of ice coverage.

5. recessional moraine: marks where the glacier once was; as it retreats, material is deposited

an example of a glacial landform in the uk

Cadair Idris and Llyn Cau, Wales (textbook page 155)

economic activities in glaciated areas (4)

tourism, forestry, sheep/arable farming, quarrying

how can these economic activites cause conflict?

quarrying: pollution of land + rivers, destroys habitats/landscape, noisy

tourism: tourists litter, footpath erosion, conflicts with farmers (leaving gates open etc), house prices up

farming: grazing sheep remove vegetation- conflict with conservationists, conflict with tourists over farm sites access

forestry: harvesting trees = chopping down forests + destroys habitats, conflict with conservationists as coniferous forests don’t support as many species as natural woodlands.

example of a conflict in a glaciated area

Glenridding zip wire proposal by Treetop Trek in 2014 (Lake District)

example of a glaciated area in the uk used for tourism (case study)

the Lake District

details in my book!