Coastal / UK landscapes Flashcards
Marine processes
erosion, transportation, deposition
subarial processes
weathering and mass movement
Abrasion (or corrasion)
the scraping, scouring or rubbing action of materials being carried by moving features such as rivers, glaciers or waves, which erode rocks
attrition
When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.
Hydraulic action
The pressure of compressed air forced into cracks in a rock face will cause the rock to weaken and break apart.
Solution
rocks being chemically changed such as its either taken into the solution or removed
traction
large stones or boulders are rolled along the floor of the river
Saltation
small rocks are bounced along the bottom of the river bed
solution
material is dissolved and carried along in the river
Suspension
- Small/fine sediment can be transported in the current of the waves/body of the water
What is longshore drift?
- Sediment can be transported by longshore drift.
- Sediment is moved up the beach by the swash at an angle
- and back down the beach at 90o by the backwash.
examples of weathering
biological, chemical, phycisal and freeze thaw
Examples of mass movement
landslides, slumps, falls
examples of landforms from coastal erosion
cave, arch, stack, stump, headland, bays, WCP, WCN, cliff
factors influencing erosion
weather/temperature, tides, depth of water, shape of coastline, wind, humans, type of wave
Concordant coastline
In this type of coastline, the layers of rock are parallel to the direction of the coastline.
Disconcordant coastline
Rock type runs 90° to coast
charateristics of beaches
- gently sloping, very low angle to the beach
- streches far inland
- can be found in bays or along streches of the coastline
- tourist resorts use groynes to keep the beaches in place
How are spits created?
- When the coastline ends but longshore drift continues, so sediment is deposited off the coast.
- if conditions are right the sediment will build up and form new land.
- the swash travels up the beach at an angle and the backwash travels back down the beach at 90dgrees due to gravity.
- a change in the prevailing wind will make a hooked end.
- The prevailing wind determines the direction of LSD
what is biological weathering?
This is caused when plants or their roots push or pull rocks apart.
what is chemical weathering?
The process that breaks down rock through chemical changes
what is mechanical weathering?
the breakdown of rock into smaller pieces by physical means
what is a bay?, what type of coastline does it form on
an indentation in the coastline between two headlands. they are made of less resistant rock than headlands, and the land has been eroded back by the sea
—> Discordant coastline
What is a headland?
a narrow piece of land that projects from a coastline into the sea. it is serouneded by sea on 3 sides
how are cracks in headlands formed?
As headlands aren’t made from all the same rocks there are small joint in the rock. Water is forced into the crack enlarging it - this is called hydraulic action. Also where the sea picks up material and throws it at the headland the material sandpapers away the headland this is called abrasion. This also makes the crack bigger
how is a caved formed
caves occur when waves force their way into cracks in the cliff face. The water contains sand and other materials that grind away at the rock until the cracks become a cave. Hydraulic action is the predominant process
How is an arch formed?
As a cave is formed, erosion continues either side of the headland and once the caves conjoin either side, an arch is formed.
How is a stack formed from an arch?
the ceiling of the cave may become to heavy to is collapses and then forms a stack. they are normally thinner at the bottom as they are worn away by erosion
how is a stump formed
when the stack is eroded it form a stump that will only be visble at low tide.
What are the different types of weathering
- Chemical
- Freeze-thaw
- Biological
What are the different types of mass movement
- Slides
- falling
- Slumps
define mountain
area of land that rises considerably above the surrounding land, with 600m sometimes used as the height that separate mountains from hills
what is the Holocene
- the period of time that describes the recent 10,00 yrs state of the UK landscape
How was the UK landscape formed
- Glaciers eroding and weathering the landscape
- ice scoured out deep valleys (Glencoe)
- ice scraping away soil in low land areas, bulldozing clay and boulders into ridges (Norfolk coast)
- or leaving piles of rock that differ from local geology
What are the 3 rock types based off origin
Igneous, Sedimentary, metamorphic
why might rock be more exposed in mountainous areas
ice removing the surface covering during an ice advance.
How is igneous rock formed
- magma cools
- intrusive (beneath ground) or extrusive (above the surface)
- Formed from when there was volcanic activity in UK
- Mainly in North (there’s extinct volcanoes in Scotland)
Give examples of igneous rock types and where they’re found
- Granite (intrusive) = Dartmoor
- Gabbro (intrusive) = Cuillin Hills
- Basalt (extrusive) = Island of Arran, Scotland
How is sedimentary rock formed
- skeletons of marine microorganisms and other sediment
- laid down and compacted at compacted at the bottom of oceans
examples of sedimentary rock types and where they’re found
- Chalk = Dover
- Limestone = Yorkshire Dales
- Gritstone = Peak District
How is metamorphic rocks made
- Heat + pressure on existing igneous or sedimentary rock
- changes the structure of these rocks, forming a new type
Examples of metamorphic rock types
- slate = North Wales
- Gneiss = Lewis
where are the areas of deepest soil and what influences what grows there
- South
- geology of underneath rocks
what does the soil that was reclaimed from beneath the sea and the drained look like
- dark silty soil
- they are deep soils with no stones
- its texture means that it drains well and warms up quickly
how are waterfalls formed
- river flows over bands of rock which vary in resistance to erosion
- weaker rocks are eroded faster
- creating a steep gradient between hard and soft rocks
- river flows faster, over a sudden drop that’s marked by the edge of the more resistant rocks
- softer rock becomes even more steeper
- over hang of hard rock is created
- deep plunge pool is created and turbulence in the pool erodes the back wall of the waterfall further
