8.1 COASTAL PROCESSES Flashcards
littoral zone?
wider coastal zone including adjacent land areas and shallow parts of the sea just offshore
name the 4 subzones of the littoral zone…
- backshore
- foreshore
- nearshore
- offshore
what are the 2 diff coast types?
-rocky
-coastal plains
features of a cliffed coast? (3)
-abrupt transition from land to sea
-at low tide, the foreshore zone is exposed as a rocky platform
-vertical cliffs
features of a sandy coastline? (2)
-at high tide the sandy beach is inundated
-it prevents erosion through the dune vegetation
features of an estuarine coastline? (2)
-extensive mud flats
-gradual transition from land to sea
what are primary coasts dominated by?
-dominated by deposition
what are secondary coasts dominated by?
-dominated by marine erosion
what is an emergent coast?
-coasts that are rising relative to sea level
what is a submergent coast?
-being flooded by sea
what are the three tidal ranges and what is the range?
microtidal (0-2m)
mesotidal (2-4m)
mactrotidal (>4m)
what would small waves be caused by? (4)
-low energy
-sheltered coasts
-limited fetch
-low wind speeds
what would big waves be caused by? (4)
-high energy
-exposed coasts
-facing prevailing winds
-long wave fetch
what is a cliff profile?
-height and angle of cliff face as well as features
-e.g cut out notches
where marine erosion dominates, what features are there?
-steep cliffs
-limited base debris
-active undercutting
where sub-aerial processes dominates, what features are there? (3)
-curved slope profile
-lower angle face
-accumulated debris
what is coastal accretion?
-build-up of the coast through deposition from sea + land via rivers
whats dynamic equilibrium?
-balance between inputs and outputs through feedback overtime
what is weathering?
-chemical, biological and mechanical breakdown of rocks into smaller fragments and new minerals
what is mass movement?
-landslides, slumps and rock falls
-which move material downslope under the influence of gravity
what is surface runoff?
-water, usually during rain, falling down cliff face and causing erosion
resistance is influenced by? (3)
-how reactive minerals in the rock are when exposed to chemical weathering
eg calcite can be weathered by solution but quartz is not subject to chemical weathering
-is rocks are clastic
-degree at which rocks have cracks
coastal recession rate for granite? and what lithology is it?
0.1-0.3
igneous
coastal recession rate for limestone? and what lithology is it?
1-2
sedimentary
coastal recession rate for chalk? and what lithology is it?
1-100
sedimentary
coastal recession rate for sandstone? and what lithology is it?
10-100
sedimentary
coastal recession rate for boulder clay? and what lithology is it?
100-1000
unconsolidated
how do coastal plains form and give an example? (3)
-result of a fall in sea level exposing the seabed of what was once a shallow continental shelf (eg Atlantic coastal plain in USA)
-depostion of sediment from land
