Coastal Landscapes 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 and low 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 are Coastal plain landscapes
-low, flat relief areas
-soft rock areas
-low energy environment
-rock types: weaker, younger sedimentary rocks- chalks, clays, sandstones
-deposition is greater than 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 4 ways
-geology
-sea level change
-energy inputs
-sediment inputs
-advancing/ retreating
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
What are concordant coasts
- have geological strata that runs parallel to the coast
-outer hard rocks acts as a 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)
-dalmatian
-haff
What are discordant coasts
-form when different rock strata intersect the coast at an angle
- differing erosion leads to
formation of headlands and bays - Less resistant rocks are eroded to form
bays
-more resistant geology
remains as headlands
-swanage bay
-bantry bay
What produces concordant and discordant coasts
geological structure
Definition of coastal morphology
shape and form of coastal landscapes and their features
Definition of coastal recession
another term for coastal erosion
Definition of strata
layers of rock
Definition of bedding planes (horizontal cracks)
natural breaks in strata caused by gaps in time during periods of rock formation
Definition of joints (vertical cracks)
fractures caused by contraction as sediments dry out/ earth movement during uplift
Definition of folds
formed by pressure during tectonic activity
-makes rocks buckle and crumple
Definition of faults
major fractures in rock produced by tectonic forces
-faults then move along fault planes
Definition of dip
the angle at which rock strata is
Definitoon of lithology
physical characteristics of particular rocks
What affects the speed at which the coast erodes
-geology
-lithology
Name 3 characteristics of igneous rocks
-is erosion rate fast/ slow
-give examples of igneous rocks
-crystalline
-resistant
-impermeable
-VERY SLOW erosion rate
-granite
-basalt
-dolerite
Name 3 characteristics of metamorphic rock
-is erosion rate fast/ slow
-give examples of metamorphic rocks
-very hard
-resistant
-impermeable
-SLOW
-slate
-schist
-marble
Name 3 characteristics of sedimentary rock
-is erosion rate fast/ slow
-give examples of sedimentary rocks
-formed in strata
-jointed sedimentary rocks (sandstone and limestone)- permeable and resistant
-other sedimentary rocks (chalk)- air spaces between particles- porous
What are Haff Coasts
-type of concordant coastline
-long spits of sand and lagoons- parallel to coast
Where is the Haff Coastline named after
Haffs/ Lagoons of the Baltic Sea
What is differential erosion
When different types of rocks are eroded at different rates
Name 2 characteristics that influenece cliff profiles
-rocks resistance to erosion
-dip of rock strata in relation to coastline
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
Definition of a cliff profile
the height and angle of a cliff face
What 3 geological features influence cliff profiles
-faults
-joints
-fissures
What controls the location of microfeatures
the location of faults and/ or strata which have a high density of joints and fissures
What are microfeatures in cliffs
caves, wave-cut notches