coasts genrel Flashcards
5 costal sediment sources
rivers and streams
cliff erosion
off shore sandbanks
estries
biological (coral fragments and shells)
5 features of a sediment cell
varying in size
area of coatsline srprating each other
closed system
inputs and outputs balanced
boundries and headlands
headlands and bays
inputs - geology, angle of dip, nature of waves, strength of wind
process - rate of erosion on rocks
wave refraction
erosion of headland
outputs - (what features are created) headlands and bays, erosional features of headland, differing features of bays
how are wave cut platforms formed
- high enery waves breack at foot of cliff
- concentrated erosion at base
- undercut cliff
- wave cut notch
- casues pressure on cliff above
- collapse over time
- cliff line retretes
- craetes wave cut platfom
- rough surfcaces, erosion reduced
features of high energy waves
high energy waves = high erosive power
erosion exceeds deposition
atlantic coast
landforms that are created from high energy envroments
headlands
cliffs
wave cut platforms
features of low energy waves
deposition exceeds erosion
constructive waves
LOW ENERGY
swash is stronger then backwash
destructive waves
HIGH ENERGY
backwash is stronger then swash
concordant coastline
parellel - same rock type runs along the whole coastline
discordant coatsline
horizontal, altering bands of diffrent rock
traction
big rocks rolling
saltation
medium rocks bouncing
suspension
small rocks floating
solution
dissolved sediment
what effects rates of erosion
- wave steepness and breaking point
- waves breaking at foot of cliff and releasing more energy
- fetch
-sea depth ( if the sea becomes deep quickly then this this creates high energy waves, if sea bed was flatter then they would lose energy over time
-coastal configuration
-beach presence (beaches absorb energy)
marine coastal erosional process
- hydraulic action
- abrasion of collision
-attrition
-solution
hydraulic action
force or impact of water on rocks
weakness rock surface
abrasion or collosion
things that are carried by the sea e.g sand shillgels and bolders, material in the sea that wears away the rock
attrition
rocks in the sea carrying out erosion, worn down into smaller peices
solution
dissolving of calcium based rocks
happens in areas where fresh water mixes with sea water
geomorphical procsess
subaerial
marine
weathering
subarial
oprates on land but shapes the coatsline
emergent landforms
raised beaches - formed when the sea levels where higher then they are now
raised beaches are former wave cut platfoms
submergant landforms
Rias and Fjords
Rias
floodplains vanish benth rising sea water
RISING SEA LEVELS DOROWN RIVRER VALLYS
vallys filled with sea water
Fjords
DROWNED GALCIAL VALLYS
streightm narrow and steap sides
not the deepest at the mouth
longshore drift
waves hitting at a angle, pulling back, removing sediment e.g sand, sand is being moved along the beach in the direction of prevailing wind
whats used to prvent - groynes
source of costal sediment
terrestrial
weathering and mass movemnt
biological
marine erosion
terrestrial
fluvial deposition
river transport sediment obtained via erosion, weathering and mass movement along the course of the river and deposites it along the coats
