Geography #1C physical landscapes Flashcards
definition of relief:
height and slope of the land
definition of upland:
an area of high land; higher above sea level
definition of lowland:
an area of low lying land compared to the surrounding land; not very high above sea level
definition of igneous rocks:
formed when molten magma from the earth’s interior cools
eg. basalt, granite
definition of metamorphic rocks:
formed when subjected to massive heat / pressure deep within the earth
eg. marble, slate
definition of sedimentary rocks:
formed when sediments from the bottom of the sea compress over million of years
eg. sandstone, limestone
how are waves created?
by wind blowing over the surface of the sea creating friction and producing a swell in the water
the energy of the wind causes water particles to rotate inside the swell thus moves the wave forward
the size and energy of a wave is influenced by:
fetch -the distance the wave travelled
wind speed -amount of time the wave has been blowing
wind strength
what 3 things do wave do?
erode, transport, deposit
definition of swash and backwash:
swash -waves travelling to the beach
backwash -waves travelling back to the sea
definition of wave refraction:
the process where waves change direction as it approches the shore.
The energy of the wave is focused on the headland which erode the headland and deposit the bay, smoothing out the coastline.
erosion and the 4 different types:
erosion is the removal of material by waves:
hydraulic action -force of destructive waves hitting the cliff
abrasion -rocks being thrown against the cliff
attrition -rocks grinding together
solution -rocks being dissolved in water
2 types of waves and their characteristics:
destructive waves
-found in exposed bays
-stormy weather condition
-stronger backwash
-long wave height
-short wavelength
-high frequency
-strong wind
-erode beaches
constructive waves
-found in sheltered bays
-calm weather condition
-stronger swash
-short wave hight
-long wavelength
-low frequency
weak wind
-deposit material + build up beaches
types of transportation:
traction -rolling
saltation -bouncing
suspension -floating
solution -dissolving
longshore drift -along the coastline
describe longshore drift:
when waves strike at an angle because of the direction of the prevailing wind;
the swash carries material up the beach and the backwash carries it back down;
this motion repeats itself in a zigzag motion
definition of weathering:
the breaking down of rocks by processes in situ (where they are) caused by day to day changes in the atmosphere.
3 types of weathering and their process:
mechanical weathering (freeze thaw action) -the disintegration of rocks by physical forces
1 -occurs when water enter rocks with natural weaknesses
2 -water freezes and expands in the crack
3 -ice melts and water goes deeper into the crack, pushing it apart even more
4 -this cycle repeats until the the rock splits
biological weathering -living beings attacking rocks and weaken their structure
1 -plant roots grow in cracks
2 -the roots push the crackes making them wider
3 -the rock splits
chemical weathering
1 -rain water containing carbon dioxide reacts with the calcium carbonate in rocks
2 -this dissolves and wash away in solution, weakening the rock
definition of deposition
and the factors of it occuring:
When the sea loses energy and drops the material it had been carrying:
-Waves lose energy
-sheltered areas where constructive waves are dominant
-shallow water to allow swash to deposit
-little to no wind
-engineered structures to trap sediment
definition of mass movement:
downslope movement of rock, mud, or soil under the movement of gravity, causing the cliff to retreat.
Types of mass movement:
rockfall -fragments of rock fall off the clif face, usually due to freeze-thaw weathering
landslide -large blocks of rock slide downhill
mudflow -saturated soil flows down a slope
rotational slip -saturated soil slides along a concave plane
Differences in discordant coastline and concordant coastline:
discordant coastline -bands of different rock types running perpendicular to the coastline
concordant coastline -same type of rock running parallel to the coastline
types of erosional features
headlands and bays
wave cut platforms
cave, arch, stack, stump
Describe how bay and headland form and their characteristics:
Bay -Formed from soft rocks which erodes quickly; is a crescent shaped indentation, and usually has a beach
Headland -formed from hards rocks which erokdes slower; is a cliff that juts out to the sea
Descibe how a wave cut platform forms:
1 -the sea attacks the base of the cliff between the high and low tide level.
2 -continous erosional processes (hydraulic action and abrasion) forms a wave cut norch.
3 -the section above the norch (overhang) becomes unspported and collapses, leading to the retreat of the cliff face.
4 -the backwash carries away the eroded material, leaving a wave cut platform.
5 -the process repeats and the clif continues to retreat.
describe how the CASS forms
1 -Cracks are widened in the headland through the erosional processes of hydraulic action and abrasion.
2 -As the waves continue to grind away at the crack, it begins to open up to form a cave.
3 -The cave becomes larger and eventually breaks through the headland to form an arch.
4 -The base of the arch continually becomes wider through further erosion, until its roof becomes too heavy ehich is vulnerable to freeze-thaw weathering and collapses.
5 -This leaves a stack which is undercut at the base until it collapses to form a stump.
definition of beach
a landform of coastal deposition formed by constructive waves
Differences in sandy and shingle beaches
sandy
-shallow gradient
-constructive waves
-stretches far inland
-sand dunes at the back
shingle
-steep gradient
-destructive waves
-not far inland
-pebbles increase in size towards the back
Describe a beach profile:
shows the gradient from the back of beach to sea
-berm crest
-high +low tides
-dunes
-backshore
-foreshore
-nearshore
-offshore
definition of sand dunes and the conditions to form
large heaps of sand that form on the back shore of a sandy beach;
-large flat beach
-large sand supply
-large tidal range
-onshore wind
-obstacle
sand dune formations
1 -beach at low tide
2 -embryo dune
3 -foredune
4 -yellow dune
5 -dune slack
6 -mature dune
Definition of spit and how it’s formed
A sand or shingle beach jutting out to the sea from the land; formed when coastline suddenly change shape or at the estuary mouth
1 -sediment is carried by longshore drift.
2 -when there is a change in the shape of the coastline, deposition occurs to form a spit.
3 -hook end form if there is a change in wind direction
4 -deposited slit form salt marshes.
Definition of a bar
when a spit grow across a bay, it can form lagoons behind it
dorset coast case study
south of england
many erosional and depositional landforms:
Swanage -headland and bay
Old Harry Rocks - caves, stacks and stumps
Chesil Beach -bar
differences between hard and soft engineering:
Hard -manmade structures to manage the coast
Soft -natural + sustainable solutions to manage the coast
examples of hard engineering
Sea walls -curved concrete walls that are placed at the foot of a cliff to reflect the waves back
✔effective at protecting the cliff
✔accessible for people to walk along
✘destroy habitats
✘expensive
Rock armour -large boulders placed at the foot of a cliff to absorb wave energy
✔cheaper + easy to maintain
✔can be used for fishing
✘difficult access to beach
✘expensive to import rocks
Groynes- wooden barriers built out at right angles to trap materials
✔relatively cheap + longlasting
✔act as wind breaks
✘need regular maintaince
✘ineffective for storms
examples for soft engineering
Beach nourishment -import sand onto an existing beach to build it up
✔preserve natural appearence
✔cheaper
✘needs to be constantly replaced
✘increase erosionn in other areas
Reprofiling -redistribute sediments from the lower part of the beach to the upper part of the beach
✔cheap + simple.
✔reduces the energy of the waves
✘ineffective in the energy is too high
✘needs to be repeated continuously
Dune regeneration -build up dunes and increase vegetation
✔relatively cheap
✔preserve natural appearence
✘ineffective against storms
✘needs to be carefully managed
definition of managed retreat
allowing the sea to flood land of low value and create new interital habitats
advantages and disadvantages of managed retreat
✔cheaper in the long term
✔conserve the natural environment
✔creates new intertidal habitats
✘require to relocate people
✘expensive in the short term
✘large area of agricultural land lost which impacts habitats
