Coastal Landscapes Flashcards
What is the littoral zone
wider coastal zone
-inc: adjacent land areas, shore, shallow part of sea
-inc: 4 sub sones; coast, backshore, foreshore, nearshore
What is dynamic frequency
balanced state of a system
-when inputs & outputs balance over time
Name the 3 ways coasts are classified
-geological characeristics (lithology, structure)
-impacts of sea-level change (rising/ falling)
-dominant coastal process (erosion/ deposition)
Name the 2 main types of coastlines formed by the littoral zone
-Rocky/ Cliffed coastlines
-Coastal plain landscapes
Name 5 characteristics of rocky coastlines
-clear distinction between land & sea due to height of cliffs
-exposure to erosive forces of sea -> high energy environments
-erosion> deposition
-destructive waves
-mainly resistant rock areas- igneous, sedimentary, metamorphic- granite, limestone
Name 5 characteristics of coastal plain landscapes
-land slopes towards sea -> transition into each other
-low energy environments
-deposition> erosion
-mainly weaker rocks- younger sedimentary rocks- chalks, clays
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
Give an example of a cliffed coast in the UK
chalk cliffs - Flamborough Head, Yorkshire
Give an example of an estuarine coastline in the UK
Lymington, Hampshire
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
How can coasts be classified because of 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- seal 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 sediment inputs
-Coasts receive sediment inputs from waves, wind, tides, currents, mass movements, tectonic processes
-sediment added to coastline through deposition
-removed by erosion
-erosion > deposition- loss of sediment- coastline retreats- eroding coastline
-deposition > erosion- gain sediment- coastline advances- building coastline
Name the 2 types of coast produced by geological structure
-concordant
-discordant
What are concordant coasts
-formed when rock strata runs parallel to coast
-generally smooth/ slightly indented coastlines
(Dalmtaian)
What are concordant coasts
-formed when rock strata runs parallel to coast
-generally smooth/ slightly indented coastlines
(Dalmatian)
What are discordant coasts
-form when different rock strata intersect the coast at an angle
- differing erosion ->
formation of headlands and bays - Less resistant rocks -> eroded -> bays
-more resistant rocks -> remains as headlands
Explain why coves are often produced at concordant coastlines
-outer hard rocks -> protective barrier to erosion of the softer rocks further inland
- Sometimes outer hard rock is punctured- allowing sea to erode the softer rocks
-cove is produced (a circular area of water with a relatively narrow entrance from the sea)
Give an example of concordant coastlines in the UK
-Lulworth, Dorset
Give an example of discordant coastlines in the UK
West Cork Coast, Ireland
Name the 2 ways coastal plains form
-due to fall in sea level exposing seabed
-deposition of sediment from land -> coastal accretion where coastline moves seaward
What is coastal accretion
deposition of sediment at coast & seaward growth of the coastline, creating new land
Why in many locations are coastal plains maintained in dynamic equilibrium
-due to balanced forces of:
-deposition of sediment
-erosion by marine action
Definition of a cliff profile
the height and angle of a cliff face
What 3 geological features influence cliff profiles
-faults
-joints
-fissures
Name 2 characteristics that influenece cliff profiles
-rocks resistance to erosion
-dip of rock strata in relation to coastline
What is differential erosion
When different types of rocks are eroded at different rates
What type of cliff profile does horizontal dip produce
-vertical/ near vertical profile
with notches reflecting strata that are more easily eroded
What type of cliff profile does seaward dip, high angle produce
-sloping, low angle profile
-with one rock layer facing sea
-vulnerable to rock slides down sea
What type of cliff profile does seaward dip, low angle produce
-profile may exceed 90 degrees
-producing overhanging rock
-very vulnerable to rock falls
What type of cliff profile does seaward dip, landward dip produce
-steep profiles of 70-80 degrees
-producing very stable cliff with reduced rock falls
Name the 2 main cliff profile types
-marine erosion dominated -> steep, unvengetated, little rock debris
-sub-aerial process dominated -> curved profile, lower angle face, accumalted debris at bottom of cliff due to mass movement
Igneous
-examples
-erosion rate
-granite, basalt
-erosion rate: v slow, resistant rock -> crystalline, have few joints
Metamorphic
-examples
-erosion rate
-slate, marble
-erosion rate: slow, resistant rock -> crystalline, folded, fractured
Sedimentary
-examples
-erosion rate
-sandstone, limestone
-erosion rate: fast -> bedding planes, fractures
