EQ 1 - Coasts
- Created by: anna_f
- Created on: 23-11-16 14:06
Sand Dunes
What are they:
- Small ridges or hills of sand covered in vegetation found at the top of a beach, above the usual maximum reach of the waves.
Formed:
- Sand and winds that blow the sand inland. Plants colonise the dunes which stabilise them.
Example of plants:
- Prickly Saltwort
- Marron Grass
- Sand Sedge
Location example:
- Ainsedale, Formby
- Mersyside
Salt Marshes
What are they:
- Areas of flat silty sediments with numerous channels running through
How are they formed:
- Shaltered areas with low energy where deposition occurs, where there are no strong tides or currents to carry away sediment
Examples of plants:
- Glasswort
- Marshgrass
- Cord grass
Location examples:
- Norfolk coast
- Eden Esturary of Fife
- Surn Head
General Formation of Vegetation
- Supply of sediment
- Low energy environment
- Initial deposition
- detntus line sand dunes
- mudflats salt marshes
- Pioneer species colonise
- sediment trap
- bind sediment
- add nutrients
- Landforms develop
- mudflats height increase (salt marsh)
- mobile dunes develop (dunes)
Impact of vegetation
Surrounding area:
- Prevents flooding / erosion
- Can be built on once stable
- Tourism
- Helps maintain a wide beach
Brings stability:
- Sediment trap
- Stabilises - binds sediment
- Adds nutrients
- Retains water
- Stops flooding
- Stops erosion
Discordant and Concordent Coastlines
Rock types:
- Chalk
- Welden Clay
- Portland + Purbeck Limestone
Discordent:
- Perpendicular to coastline
Concordent:
- Parallel to coastline
Littoral Zone - inputs
Inputs:
- Supply from land
- Coast erosion
- Beach nourishment
- Sand supply from rivers
- Reversible processes
- Wind transportation
- Releasing / trapping of land
- Decrease supply from land
- Trapping sand at structures
- Coast protection
- Beach sand mining
Littoral Zone - outputs
Outputs:
- Offshore supply
- Onshore transport
- Shore face nourishment
- Reversible processes
- Calcium carbonate production and loss
- Offshore loss
- Nearshore submarine canyon
- Dredging
- Offshore transport during storm and tidal wave conditions
- Offshore loss due to sea level rise
Areas of the Littoral Zone
- Sea
- Backshore
- Foreshore
- Nearshore
- Off-shore
- Land
Beach System - Inputs
Short term:
- Climate
- Storm surges
- Waves
- Tides
- Wind
- Weather
Long term:
- Climate change
- Tectonic activity
- Ocean currents
- Rock type
- Human activity
Coastal System - Inputs
Inputs:
- Waves
- Tides
- Storm surges
- Ocean currents
- Wind
- Weather
- Climate
- Climate change
- Rock type
- Vegitation
- Tectonic activity
- Human activity
- Coastal management
Coastal system - Processes
Processes :
- Hydraulic action
- Abrasion
- Corrosion
- Attrition
- Saltation
- Traction
- Suspension
- Long-shore drift
- Freeze-thaw
- Chemical
- Biological
- Accumulation
- Flocculation
- Slides
- Creep
- Slump
Coastal System - Outputs
Outputs:
- Cracks
- Caves
- Arches
- Stacks
- Stumps
- Blowholes
- Wave-cut platforms
- Sand dunes
- Beaches
- Tombolos
- Spits
- Bars
- Dalmation coasts
- Haff coastlines
- Slides
- Creep
- Slump
Low-energy coast
- Waves
- Calmer conditions
- Short fetch
- Less powerful waves (constructive)
- Sheltered from largest waves
- Processes
- Deposition and transport
- Sediment from river, longshore drift and nearshore currents
- Landforms
- Beaches, spits, salt, marshes, sand dunes, bars, mudflats
- General location
- Coastal plain landscape
- Lowland landscape
- Example locations
- East Anglian
- Mediterranean
High- energy coast
- Waves
- Long fetch
- Most powerful waves (constuctive)
- Exposed to largest waves
- Storm condidtions
- Processes
- Erosion and transportation
- Sediments from eroded land, mass movement and weathering, off-shore currents
- Landforms
- Cliffs, wave-cut platforms, arches, sea, caves, stacks
- General location
- High land and lowland coastline
- Rocky landscape
- Example locations
- Atlantic coasts of Norway and Scotland
Rock angles
1. Rocks dipping towards coastline wunerable to mass movement
Soft clay erodes more quickly chalk is unsupported
Joints make the cliff face more unstable
2. Coal seam erodes more quickly then sandstone creates hang
Glacial boulder clay unconsilidated so slides off the cliff
3. Vunerable to erosion in weaknesses, can hold its form holding arches
4. Not vunerable to erosion
No joints/ bedding planes
Steep cliff
5. Creates mass movement along bedding planes
Igneous, Sedimentary, Metamorphic
Igenous:
- Formed when magma is cooled
- E.g. Granite/ Magma
Sedimentary:
- Formed by small particles, forming layers in the the water, compressed
- E.g. Granite/ Basalt
Metamorphic:
- Formed by heat and pressure changing the rocks
- E.g. Slate (clay)/ Limestone (marble)
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