Coasts Flashcards
What is the littoral zone?
The boundary between the land and the sea
Why is the littoral zone dynamic?
Because the boundary moves depending on the tide, and sea level change
Define the back shore?
The area above the waves’ influence
Define the nearshore
The area where waves break
Define the offshore
The area out at sea beyond the waves’ influence
What short-term criteria classify coastlines?
River discharge, high/low tide, weather
What long-term criteria classify coastlines?
Geology, sea-level change, high/low energy, rate of erosion
What kind of landforms do high-energy coasts form?
Rocky landforms
Where do high-energy coasts occur?
Where there is a long fetch
Where erosion > deposition
What kind of rocks are resistant, and erode slower?
Igneous
What three factors erode the coast?
Sea, rain, wind
What are coastal plain landscapes formed from?
Weaker, younger, sedimentary rock
What feeds coastal plains?
Sediment from river discharge; ocean deposition
Describe concordant coasts
“Bands” of rock types parallel to the coast. This forms “smooth” coastlines or Dalmatian coasts
Describe discordant coasts
“Bands” of rock types perpendicular to the coast. Soft rock erodes quicker, forming headlands and bays
How do coves form?
A band of hard rock is eroded through, and the soft rock behind it starts to erode much quicker
How does a Dalmatian coast form?
Sea-level rise fills in the concordant valleys between ridges
Define strata
Layers of rock
Define bedding planes
Horizontal cracks/gaps, caused by time differences in when rocks formed
Define joints/fractures
Vertical cracks caused by movements in the earth
Define folds
Rocks buckle and crumple due to tectonic activity
Define faults
A rock fractures, then slips along the fault plane
Define dip
The angle of the strata
What is the order of coastal plant succession?
Embryo, fore-, yellow, grey, dune slack, woodland
What are colonising coastal plants called?
Pioneer species
How do pioneer species help plant succession?
They bind sand/soil, and add nutrients when they decay, allowing larger plants to grow
What kind of plants are found at yellow dunes?
Marram grass
What kind of plants are found at grey dunes?
Low shrubs
What kind of plants succeed pioneer species?
Invader species
What is the peak of a coastal ecosystem called?
Climatic climax community
What are the characteristics of a constructive wave?
Low waves, long wavelength
Strong swash, weak backwash
Beach gain
Wave energy absorbed by beach
What are the characteristics of a destructive wave?
High waves, short wavelength
Weak swash, strong backwash
Beach loss
Wave energy NOT absorbed; attacks the cliff face
Why does beach morphology change with wave type?
They are made of loose material; sand
When is sediment removed from beaches?
Winter
What are the characteristics of winter at a coast?
Storms and destructive waves
What wave type characterises summer at a coast?
Constructive waves
When is sediment returned to beaches?
Summer
Explain what season the beach profile is steepest
Summer, as sediment is deposited into a berm
Define abrasion
Sediment/rocks are thrown at the cliff base, eroding it
Define hydraulic action
Water trapped in cracks increases pressure, air expands when it subsides. This repeated process causes erosion