The Coastal System Flashcards
Definition of littoral zone
Dynamic area of change and refers to the coastal area that is effected by waves (different parts of the coast are terrestrial and dynamic and therefore undergo short term changes that created classifications of a coastline)
5 aspects the littoral zone refers to
1) coast land affected by the sea and may include the settlements and farmland
2) backshore is the area that sits above the tide level and coastal processes only affect the backshore when there’s an extreme weather event such a a storm or an extreme high tide
3) the foreshore marks the zone between the high and low tide mark. This is a place where many wave processes take place
4) the nearshore is the area just off the coastline beyond the low tide level and cosists of shallow sea water
5) the offshore is the open sea where waves start to break and water is deeper
3 long term changes create coastlines that are
1) emerging or submerging depending on whether sea level is falling or rising
2) rocky or estuarine, depending on geological resistance to weathering and erosion
3) Concordant or discordant depending on the relative position of geological strata and wave action
Tidal range definition
Difference in height between high and low tides
4 short term changes create coastlines that are
1) classified by tidal range
2) retreating (losing land) or advancing (gaining land), dependin on wether erosion or deposition dominates the site
3) high or low energy coasts depending on the balance between erosion and deposition taking place there
4) dominated by land-based processes (primary coasts) or by marine based processes (secondary coasts)
Features of high energy coasts (6)
1) large powerful destructive waves
2) exposure to strong winds, long fetches and steeply shelving offshore zones
3) high rates of erosion than the rate of deposition al;though the geology of some high energy coastlines make them more resistant to erosion
4) tend to be rocky coasts with sandy coves and rocky landforms such as cliffs, stacks and arches (clear distinction between land and sea
5) high erosion levels that tend to be steep with little vegetation (waves undercut cliff and wash away debris - marine cliff profiles
6) high levels of weathering that tend to be less steep with weathered material at base
Cliff subariel cliff profile
Where can high energy coastlines be found
Stretches of Atlantic facing coast )Cornwall or North-wester Scotland)
Definition of high energy coastline
Rate of erosion exceeds the rate of deposition
Definition of low energy coastline
Where rate of deposition exceeds rate of erosion
Where can low energy coastlines be found
Where waves are less powerful or where coast sheltered from large waves (Northumberland or lincolnshire)
5 features of a low energy coastline
1) small, gentle constructive waves
2) created by gentle fetch and sheltered location, short fetches and gentle sloping offshore zones - reef may protect coast
3) higher rate of decision than erosion
4) characterised by sandy beaches, salt marshes, estuaries, and tidal mud flats, but no cliffs next to the beach (cliffs back from coast)
5) land with gentle relief and low elevation
Inputs into the coast system
- marine - waves tides and storm surges
- atmospheric - weather/climate, climate change, solar energy
- land - rock type and structure, tectonic activity
- people - human activity, coastal management
Processes in coast system
- weathering
- mass movement
- erosion
- transport
- deposition
Outputs in coastal system
- erosional landforms
- depositonal landforms
- different types of coast
What are the 4 different sections of the littoral zone
- Backshore - usually above the influence of the waves
- foreshore - inter-tidal or surf zone
- nearshore - breaker zone
- offshore - beyond influence of the waves
Where is the main source of cliffs eroding
West runtime mad Weybourne (along Norfolk cost) where cliffs been retreating by nearly 1m power year because they are sandstone (60% sandstone)
4 ways of classifying coasts
- geology - creating rocky, sandy amd estuarine costs as well as Concordant and discordant coasts
- energy - high or low energy coasts
- balance - erosion and deposition (which more dominant process) - erosional or depositional coasts and their associated features
- sea level - either emergent or submerging coasts
Where is the Jurassic coast located
Southb Devon and east Dorset and is widely regarded as being amouingst the most stunning scenery in the UK
What is the lull worth crumple
Stair hole on Jurassic cost hall a mile away from llulworth covr. Sea has eroded through limestone and classy to create a small cove and it is the best place the see the ‘Lulworth crumple’ and best examples of limestone folding
Definition of coastal morphology
Underlying geology or rock type but it is also the geological structure
What are strata
Layers of rock
What are bedding planes
Horizontal cracks caiused by either contraction as sediments dry out or by earth movements during uplift
What are joints
Vertical cracks - fractures caused either by contradiction as sediments dry out or by earth movements during uplift
What are folds
Formed by pressure during tectonic activities makes rocks buckle and crumple (Lulworth crumple)
What are faults
Formed when stress or pressure to whcih a rock is subject exceeds internal strength and the faults then slip or move along fault planes
What are dips
Angle at which rock strata lie (horizontally, vertically, dipping towards sea or dipping inland)
