Coastal Landscapes and Change Flashcards
What is the littoral zone and what are its four subdivisions in order
The coastal zone in which sediments are moved around between the ladn, beach and sea
It consists of the offshore, the nearshore, the foreshore and the backshore
What are the four types of coasts classified by advancing or retreating
Emerging Coast (Advancing Coast)
Submerging Coast (Retreating Coast)
Outbuilding Coast (Advancing Coast)
Eroding Coast (Retreating Coast)
What the the following characteristics of high energy coasts?
Wave Characteristics: (1)
Processes: (3)
Landforms: (6)
General Location: (3)
- Wave Characteristics: Destructive
- Processes: Erosion and transport, mass
movement, weathering - Landforms: Cliffs, wave-cut platforms, caves, arches, stacks, stumps
General Location: Rocky landscapes, highland and lowland coasts, exposed to largest waves
What the the following characteristics of low energy coasts?
Wave Characteristics: (1)
Processes: (2)
Landforms: (5)
General Location: (3)
- Wave Characteristics: Constructive
- Processes: Deposition and transport, longshore drift
- Landforms: Beaches, spits, bars, sand dunes, salt marshes
- General Location: Coastal plain landscapes, lowland coasts, sheltered from largest waves
Name the 4 types of inputs of the coastal system
- Marine: Waves, tides, storm surges etc
- Atmospheric: Climate change, weather/climate
- Land: Rock type, tectonic activity
- People: Human activity, coastal management
Name 5 main processes in the coastal system (Think GCSE)
- Erosion
- Weathering
- Mass Movement
- Transport
- Deposition
What are the 3 factors affecting the energy of a wave
- Wind Speed
- Wind Duration
- Fetch (distance the wave has moved)
Why do tides exist
The sea is affected by the gravity of the sun and the moon (mostly the moon as its closer) so the water is pulled towards the moon which depending on the position of the moon tides are either high or low
What is a spring tide and what is a neap tide
A spring tide is the highest point a tide will go and occurs twice a lunar month when the sun earth and moon perfectly line up
A neap tide is the lowest point a tide will go and occurs twice a lunar month when the sun and earth moon perfectly form a right angle
how long is a lunar month
Approximately 29.5 days
Why do some places have such different tidal ranges compared to others
The shape of the coastline and its position on Earth can affect how much variation in tides there are
Name one place with a low tidal range and one place with a high tidal range and the effect of the tides on their coastlines
A place with a low tidal range is the Mediterranean which causes there to be limited wave action and erosion
A place with a high tidal range is the UK which causes there to be much more coastal erosion
What is a sediment cell
A section of a coastline where sediment moves between the beaches, cliffs and sea. Cells are usually divided by a physical barrier like a large headland which prevents most movements of sediment between cells
How many major sediment cells are there in England and Wales
11 (with subsections eg 5d, 5e, 5f etc)
Are sediment cells closed systems
Sediment cells are mostly closed systems but small amounts of sediment movement in or out is inevitable
Give an example of a minor sediment cell around the UK
South Isle of Wight (sediment moves from the destructive Needles coastline to the constructive Sandown Bay coastline)
Why do waves break (4)
- Waves usually move forwards in a circular motion (water at the top of the wave goes to the bottom and vice versa)
- When waves get close to the coastline they make contact with the seabed which exerts friction onto the wave
- This leads the wave to move from a circular motion to an elliptical one
- Over time the friction increases to the point where the crest of the wave tips over the front which is a wave breaking
What is the difference between geology and lithology?
Geology is the study of the classification of rocks and their origion
Lithology is the study of physical properties of rocks, such as their texture or features
What is Strata
Thin layers of (usually) sedimentary rock formed at the Earth’s surface which each have internally consistent characteristics which distinguish it from other layers
What are Bedding Planes
Horizontal Cracks dividing rocks which signify a change in the depositional conditions which affect the formation of each distinct layer of sediment
What is a possible depositional change that can occur and create bedding planes
Floods or severe storms
What are Joints
Vertical cracks in rocks which often pull away from each other
What are Folds
When layers of rocks or strata are permanently bent or curved as a result of pressure or tectonic activity
What are Faults
A crack in the crust of the Earth; often form tectonic plate boundaries
What is the Dip of a rock
The angle at which the Strata lies (eg diagonally, horizontal, vertical)
What are the three main categories of mass movement
- Flows
- Slides
- Slumps
What are the 3 types of flows in mass movement
- Soil Creep (long term downhill movement of soil particles)
- Solifluction (In tundra areas where the ground is frozen, when the top layer of soil thaws but the rest doesn’t, the top layer flows downhill over the rest of the soil)
- Earthflows/Mudflows (An increase in water, usually from rain, reduces friction which can make earth and mud flow downhill easier)
What are the two types of slides in mass movement
- Rock Fall (When weathering weakens a rock causing it to fall out of a cliff)
- Rock Slides (When rocks slide downhill as a result of rainfall reducing friction, more susceptible in rocks with joints or bedding planes)
What are slumps in mass movement
When soft material like clay or sands slide down harder rock like granite in a rotational movement
What is the different between flows, slides and slumps
Flows are unique as all the material is mixed and jumbled whereas in a slide or slump the material remains intact
Slumps are unique because it has a rotational movement
What are the three types of weathering
Biological, Chemical, Mechanical
Name the two categories of landforms that form as a result of coastal processes (aka the outputs in the coastal system)
- Erosional Landforms (eg caves)
- Depositional Landforms (eg beaches)
Give 3 fixed factors influencing the rate of erosion
- Geology
- Lithology
- Exposure
Give 3 variable factors influencing the rate of erosion
- Storms
- Wind Direction
- Season
Describe the formation of wave cut notches and wave cut platforms
Waves erode at the high tide line at the bottom of a cliff, breaking away a gap in the cliff called a wave cut notch.
Over time the wave cut notch will get larger until it causes the cliff above it to collapse.
The part of the cliff just under the wave cut notch will remain.
The process continuously repeats itself causing the cliff to retreat but leaving the platform under where all the wave cut notches are forming a wave cut platform which is usually only exposed at low tide
What type of coastline allows for the creation of headlands and bays and why
Discordant - it has alternating bands of hard and soft rock
Describe the formation of headlands and bays
Found on discordant coastlines with alternating bands of hard and soft rock. The soft rock erodes quicker causing coastline retreat while the hard rocks are more resistant which means they don’t erode. This causes headlands to stick out and experience the bulk of wave power while bays often become tucked between headlands where they are often more sheltered from destructive waves
Describe the formation of caves arches stacks and stumps
Found on narrow peninsulas such as headlands. Erosion takes place on either side of a headland forming small caves on either side within the headland. Eventually, the caves meet up causing a hole to pass through the whole headland which creates an arch. Eventually the bridge over the top of the arch collapses, retreating the headland and leaving a stack which erodes over time until it collapses leaving a stump
What are the four methods of coastal transportation
- Traction (big rocks rolling across seabed)
- Saltation (small rocks bouncing across seabed)
- Suspension (small sediment which floats)
- Solution (dissolved into water)
What are the two types of deposition
- Gravity Settling: A decrease in energy causes water to drop the sediment
- Flocculation: When particles in suspension such as clay will coagulate or clump together over time until it is too heavy to carry so it is deposited
What direction is most longshore drift in the South UK and why
West to East
Longshore drift follows the direction of the prevailing winds which are usually the southwesterlies
What is a spit
When a coastline changes direction, longshore drift will still continue moving beach sediment in the same direction which causes it to extend out into the sea or a river estuary
What is a recurved spit
When a spit extends into a river estuary, once it reaches the actual flow of the river the spit can’t go any further so it bends back on itself slightly
What is a bayhead beach
A beach formed in the innermost part of a bay by deposition
What is a barrier beach / bar
A spit that extends all the way across a gap which traps a lagoon behind it
What is a barrier island
When a barrier beach becomes detached from the mainland