Coasts EQ1 Flashcards
Coastal processes
What is morphology?
Shape/ form of landscapes + features
What is a landscape?
Section of coastline made by multiple landforms
What is a landform?
Features made by processes
What is the littoral zone?
The area of shoreline where land is subject to wave action
What are the 4 section of the littoral zone?
- Backshore (above high tide, only affected by waves during spring tides)
- Foreshore (wave processes confined here between high and low tide marks)
- Nearshore (shallow wave areas close to land)
- Offshore (intense human activity)
What are rocky coastlines?
- Cliffs varying in height from few-hundreds of m
(cliffs are formed from rock-> hardness of rock is variable) - Hangman’s Cliff- Devon
What are coastal plains?
- Land gradually slopes towards the sea across area of deposited material
(sand dunes/ mud flats) - referred to as alluvial coasts
Example of a cliffed coast
Flamborough Head- Yorkshire
- Transition from land to sea= abrupt
- Low tide= exposure of wave-cut platform
- Cliffs vertical, cliff angle much lower
- DISCORDANT
Example of sandy coastline
Belgium beach
- high tide= sandy beach inundated (vegetated dune not)
- Dune vegetation plays crucial role in stabilising beach
- CONCORDANT
Example of estuarine coastline
Lymington- Hampshire
- Mud flats, cut by channels, exposed at low tide, inundated at high tide
- Closer to backshore= mud flats vegetated (salt marsh)
- Gradually transitions from land to sea
What is the coastal system?
Narrow strip where sea and land interact is shaped + influenced by natural + human variables
What are the inputs of the coastal system?
- Marine
- Atmospheric
- Land
- People
What are the processes of the coastal system?
- Weathering
- Mass movement
- Transport
- Erosion
- Deposition
What are the outputs of the coastal system?
- Erosional landforms
- Depositional landforms
- Different types of coasts
What are formation processes?
Primary coasts= land based processes (deposition)
Secondary coasts= marine erosion/ deposition processes
What is relative sea level change?
Emergent coasts= coasts rising relative to sea level
Submergent coasts= flooded by sea
What is tidal range?
- Microtidal= 0-2m
- Mesotidal= 2-4m
- Macrotidal= >4m
What is wave energy?
Low energy= sheltered coasts, limited fetch, low wind speeds, small waves
High energy= exposed coasts, face prevailing winds, long wave fetch, powerful waves
What are some short term affects at the coast?
- Tidal range
- Energy
- Dynamic equilibrium
- Weathering
- Erosion v deposition
- Sea level through earthquakes
- Storms/ weather
What are some long term affects at the coast?
- Geology
- Sea level (human cause)
- Formation process
- Ice age sea level rise/ fall
List the rock types in order from most to least resistant
- Granite
- Limestone
- Chalk
- Sandstone
- Shale
- Clay
- Sand
What is unconsolidated rock?
Material deposited with no structural integrity
(Gravels, boulders, clay, sands)
What are coastal plains + how do they form?
Coastal plains= low lying, low relief areas close to the coast
Formed-> fall in sea level exposing seabed of what was shallow continental shelf sea OR deposition of sediment from land brought down to coast by river system cause coastal accretion (coastline gradually moves seaward)
How are coastal plains maintained in a state of dynamic equilibrium?
- Deposition of sediment from river systems inland + deposition of sediment from offshore + longshore sources
- Erosion by marine action at coast
What is concordant?
Rock strata runs parallel to coastline
What is discordant?
Rock strata intersect the coast at an angle
What landforms are at discordant coastlines + how do they form?
Eg. Dorset Coast
Headlands and bays
- Less resistant rocks erode to form bays, more resistant geology stays as headlands
Why are headlands more targeted to erosion compared to bays?
(Wave refraction)
- As waves approach shallower water offshore of headland they slow down + wave height increases (friction occurs)
- Wave crests curve to fill bay and wave height decreases
- Straight wave crests refract, spreading out into bays and concentrating on headlands