Coastal Systems And Landscapes Flashcards
What do the energy obtained by wind depend on?
Wind velocity
Length of fetch
Time wind has blown
Depth of water
How does wind create waves?
Friction on the top of the water. The wind picks up and carries the water
What is positive feedback?
Amplifies the effect.
What is negative feedback?
Nullifies the effect
What features do constructive waves have?
Depositional Short fetch Low Swash>backwash Long Less frequent
What features do destructive waves have?
Destroy beaches Strong Backwash>swash Scour beaches Tall waves Frequent
How are constructive waves formed?
Approaches beach slowly , gently spills onto beach surface
Swash loses volume nd energy
Water percolates through beach material as has time to do so
Backwash weak so no material removed from besch
What do constructive waves form?
Ridges and berms
Long less steep beaches
What happens with destructive waves?
Rapidly steepen and plunge down when breaking Backwash> Inhibits Swash of next wave Little material moved up B wash pulls material down
What type of beach do destructive waves form
Steep
What is wave refraction
Irregular coastline
Waves slow at shallower water around headland
Headland waves refract around and all orthogonals (wave directions) converge =erode
Waves in deeper water towards bay Cary on going quickly. Reduction in energy nd deposit
LSD carries mat. From h into b
What controls the tides?
Grav pull of sun and moon
Moon pulls water towards it creating high tides - bulge on other side too.
Areas in between tides are low
What are spring tides
Twice a month. Sun moon and earth in straight line. Tide raising force is strongest
Higher high tides and lower low tides = HIGHEST MONTHLY TIDAL RANGE
What are neap tides
Twice a month earth90° in relation to sun and moon.
Lower high tides, higher low tides
Lowest monthly tidal range
What are the 3 types of current
LSD- waves hitting coast at an angle and transport material along coast
Rip- currents moving away from coast
Upwelling
What are sediment cells
Movement of sand and shingle sized sediment by LSD. 11 sediment cells and sediment stays in those areas
What are some erosional processes
Hydraulic action- force of water into rocks. Cavitation occurs with the loss of pressure s air bubbles come out nd can create shockwaves
Abrasion- hurled against cliffs
Wave pounding- mass of water is powerful
What are some weathering processes
Freeze thaw
Solution - dissolved minerals react with water then the rocks
Carbonation- co2 in rain reacting with rocks like limestone and chalk to create bicarbonates which react with water
Formation of cliffs and wave cut platforms
D waves
Erosion close to high tide line
Wave cut notch
Continued e
Under cut, upper part of cliff collapses (over hang) - weathering
Cliff retreats
Mat. Used to erode again or transported elsewhere
How are geos caves arches stacks and stumps and blowholes formed
D waved attack line of weakness
E into cracks
Widening crack to form narrow steep sided inlet- a geo
Widening horizontally = cave
Erosion continues upwards to top of cave- water rises up creating a blowhole
E all way through= arch
Arch collapse over time- weathering creating a stack
More e to create a stump
