Coastal landscapes and systems Flashcards
What are the zones that the littoral zone can be divided into
-name them in order
- coast
- backshore
- foreshore
- nearshore
- offshore
What is the backshore zone found in the littoral zone
-what is it
- area between the high tide mark
- affected by wave action during major storms
What is the foreshore zone found in the littoral zone
-what is it
- area between high tide and low tide mark
- seen as most important area for marine activity
What is the nearshore zone found in the littoral zone
-what is it
-area of shallow water where friction occurs between seabed and waves- causing waves to break
What is the offshore zone found in the littoral zone
-what is it
- area of deeper water beyond the point where waves begin to break
- friction occurs between seabed and waves- could cause distortion in wave shape
Name the 2 main types of coastlines formed by the littoral zone
- Rocky/ Cliffed coastlines
- Coastal plain landscapes
What are rocky coastlines
- areas of high relief
- resistant rock areas- resistant to erosive power of sea, wind, rain
- high energy environments
rock types: igneous, sedimentary and metamorphic rocks- granite, slate, limestone
- erosion is greater than deposition
- destructive waves
What is weathering
chemical, bilogical, mechanical breadown of rocks into smaller fragments in situ
What is mass movement
landslides, slumps, rockfalls all of which move material downslope under the influence of gravity
What is surface runoff
water, usually during heavy rain, flowing down cliff face and causing erosion
What is the littoral zone
-boundary between land and sea
Why does the littoral zone vary
- due to:
- short-term factors- daily tides, seasonal storms, individual waves
- long-term factors- changes to sea levels, climate change
Name the 3 coastal landscapes the littoral zone forms
- rocky, cliffed coastline
- sandy coastline
- estuarine coastline
What are sandy coastlines
areas of low relief with sand dunes and beaches, that are much flatter
form in areas with:
- less resistant geology
- a low energy environment
- where deposition > erosion
- constructive waves
What are estuarine coastlines
areas of low relief with salt marshes and mudflats (estuaries)
form:
- in river mouths
- where deposition > erosion
- in a low energy environment
- usually in areas of less resistant rock
What is coastal accretion
deposition of sediment at the coast and the seaward growth of coastline- creating new land
What is dynamic equilibrium
balanced state of a system when inputs and outputs balance over time
How are coastal plains maintained in a state of dynamic equilibrium in many locations
- deposition of sediment from river systems inland and from offshore and longshore sources
- erosion by marine action
What is a cliff profile
height and angle of a cliff face as well as its features
Name the inputs in the coastal system
inputs
- marine- waves, tides
- atmospheric- weather/ climate
- land-rock type, structure
- people- human activity, coastal management
Breakdown the coastal system
-inputs -> processes -> outputs
Name the processes in the coastal system
- weathering
- mass movement
- erosion
- transport
- deposition
Name the outputs in the coastal system
- erosional landforms
- depositional landforms
- different types of coasts
Name the 2 ways coasts can be classified
longer-term criteria:
- geology
- sea level change
short-term criteria:
- level of energy
- advancing/ retreating
How can coasts be classified by their geology
lithology (rock type) and structure of rocks
-used to determine if coast rocky, sandy or estuarine and concordant / discordant
How can coasts be classified because of sea level change
- used to classify coasts as emergent/ submergent
- can be caused by:
- tectonic processes- lift/ subside land- effects sea levels
- climate change- sea levels rise and fall
How can coasts be classified because of energy inputs
- receive energy inputs form waves, tides, currents, rivers, atmospheric processes, gravity tectonics
- classify coasts as high/ low energy
How can coasts be classified because of advancing/ retreating
classified as advancing/ retreating due to long-term processes (emergent/submergent) and short term (outbuilding/eroding).
What are the 2 main cliff profile types
- marine erosion dominated (steep face)
- sub-aerial process dominated (curved slope profile)
What factors can determine a rocks resistance to erosion and weathering
- How reactive minerals in the rock are when exposed to chemical weathering- e.g. calcite (found in limestone) can be weathered by solution, whereas quartz (found in sandstone) is not subject to chemical weathering
- if rocks are clastic/ crystalline- igneous rocks are crystalline and are more resistant, sedimentary rocks are clastic (made of cemented sediment particles
- if rocks have cracks, fractures and fissures, which are weaknesses exploited by the forces of weathering and erosion
