Coastal Landscapes 1.1 Flashcards
How can coastal landscapes be viewed as systems
- A system is a set of interrelated objects comprising of stores and flows working together to form a unit
- Energy available may be kinetic, potential or thermal
- This energy allows the geomorphic processes to shape the landscape
- The material found in a coastal landscape is the same found on beaches and the near-shore zone
what are the components of open systems
Inputs - Kinetic/thermal energy from the wind or sun - material from deposition/mass movement
Outputs -marine and wind erosion - evaporation
Throughput’s - consist of stores - including beach and near shore sediment accumulations - flows - LSD with the movement of sediment
What is system feedback
When the equilibrium is disturbed - system self-regulates to restore it - known as dynamic equilibrium - example of negative feedback
What are sediment cells
a stretch of coastline where the movement of material is self contained - an example of a closed system - 11 in the UK - Large land masses stop them e.g. Lands End
How does wind effect the coastline
source of energy for coastal erosion - waves are generated by frictional drag - larger wave speed = larger fetch - wind carries out erosion, transportation and deposition - aeolian processes
What type of energy do waves contain
Potential and Kinetic
Describe breaking waves i.e. the different types and how they work
as the waves comes closer to shore the depth decreases causing the wave to steepen and the crest to advance on the base.
-Spilling - breaks gently onto a sloping beach
-Plunging - moderately steep waves break onto steep beaches
- surging - low-angle waves break onto steep beaches
Describe constructive waves
low in height - long wavelength and frequency - break as spilling waves - swash energy exceeds backwash energy
Describe destructive waves
great height - short wavelengths - high frequency - break as plunging waves - Swashes energy is less than the backwash
What is the relationship between beach gradient and wave type
high energy waves occur in the winter months - remove material from the top of the beach and transport it to the offshore zone - low energy waves - summer months - build up the beach gradient
why do tides occur and how can they effect coastal landscapes?
Periodic rise and fall of the seas surface - gravitational pull of the moon - Tidal range - influences where wave action can occur - weathering processes happen in between tidal ranges
what is Lithology within geology
physical and chemical composition of rocks
What is structure within geology
properties of individual rock types - includes permeability - rock outcrops that run parallel to the coast = concordant coasts - outcrops which lie at right angels = discordant planforms
How do currents have an effect on coastal landscape systems
rip currents cause changes in the beach profile - creating cusps - ocean currents - created by the earths rotation - set in motion by wind - warm currents transfer heat from low latitudes - particularly effect western facing coastal areas - transfer of heat is significant - effects temperature and therefore sub-aerial processes
What is ‘Terrestrial sediment’
Sediment from rivers - 70% of sediment is terrestrial - large part of the sediment budget
