1.1.4 - factors affecting coastal coastal processes and landforms Flashcards
what are the factors affecting waves that result in coastal landforms?
wind velocity
wind duration
fetch
wave reflection
wave refraction
what occurs during wave refraction?
- shape of seabed changes the waves direction of approach, refracting it
- causes wave energy to vary along the coastline
- concentrated wave energy at headlands an more dispersed at bays
(e.g. spits hooked end)
what occurs during wave reflection?
-rocky coastlines have deep offshore water, waves get reflected back from cliffs or seawalls
-do not break at shore, reduces erosion
what three components make up the lithology of the coastline?
hardness, chemical composition, permeability
how does hardness of rock form its composition?
- hard rock = rocks that were compressed when made, making them more resistant to erosion
- soft rock = unconsolidated materials like sand and clay are less resistant to erosion
how does rocks chemical composition of a rock make it up?
certain rocks get chemically weathered faster, often due to their solubility (limestone is more prone to saltwater corrosion)
how do rocks permeability make up the composition of the coast?
pores/joints in the rock allow surface water to seep through - this builds the resistance of the rock to weathering
how do joints/cracks and fold make the coastline more susceptible to erosion?
if lots of them, weaken the rock, meaning more erosion forming features of the coast like inlets/fjords
what forms due to a concordant coastline?
dalmatian coastline
whats an example of the hard rock in nothern uk?
whin sill - cliffs and arches
whats an example of the soft rock in southern uk?
lulworth cove in Dorset - sandy beaches and unconsolidated coastline
what does a larger fetch mean?
the wave has more POWER and is physically larger
