coasts revision cards Flashcards
what are the three stages in a sediment cycle?
Inputs (where sediment comes from)
transfers (the processes)
outputs eg spits and beaches
name the four parts of the littoral zone in order
backshore
foreshore
nearshore
offshore
what are the short term factors effecting the Littoral zone?
tides and storm surges
what are the long term factors affecting the Littoral zone?
changes in sea level
climate change
what are the three tides
low
high
spring tides
what is abrasion
sediment moving along the shoreline causing it to be worn down over time
what is attrition?
wave action causes rocks and pebbles to hit against each other, causing rocks to be smaller and more round. Attrition does not cause coastal erosion
what is hydraulic action?
A wave crashing into a rock or cliff face forcing air into the cracks, the high air pressure causes the cracks to force apart and widen
when are erosion rates highest?
when waves are high and have a long fetch.
waves are perpendicular to the cliff.
heavy rainfall occurs.
Winter waves are more destructive.
rate of erosion by rock type
sedimentary highest
metamorphic second
igneous slowest
describe longshore drift.
waves hit at an angle determined by the direction of the prevailing wind. The waves push sediment in the direction of the wind in the swash. Due to gravity, the wave then carries sediment back down the beach in the backwash. This moves sediment along the beach over time.
what is traction?
large, heavy sediment rolls along the sea bed, being pushed by currents.
what is saltation?
smaller sediment bounces along the sea bed, being pushed by currents
what is suspension?
small sediment is carried within the water column (a body of water)
what is solution?
Dissolved material is carried within the water
what is a swash aligned beach?
waves break with no angle so no LSD
what is drift aligned?
waves break at an angle so there is LSD
what is deposition?
deposition occurs when a wave loses energy meaning the sediment becomes too heavy to carry, deposition is gradual.
what is gravity settling?
the waves energy becomes very low and so heavy rocks and boulders are deposited followed by the next heaviest sediment
what is Flocculation?
clay particles clamp together due to chemical attraction and then sink due to their high density
name 6 depositional landforms
Tombolo cuspate forelands offshore bars spits bars sand dunes
name the processes of transportation
traction
saltation
suspension
solution
name two depositional processes
Flocculation
gravity settling
how is a tombolo formed?
formed due to wave refraction off the coastal islands reducing wave velocity