Coasts Flashcards
(18 cards)
Geology Rocks
Igneous
Metamorphic
Sedimentary
High energy coastlines
Face the Atlantic coast
Destructive waves are powerful waves
Rate of erosion excess the rate of deposition
Low energy coastlines
Waves are less powerful
Constructive waves
Rate of deposition exceeds the rate of erosion
The Littoral Zone
A stretch of land at sea
Backshore
Foreshore
Nearshore
Offshore
Coasts and geological structure
Strata
Bedding planes
Joints
Folds
Faults
Dip
Constructive waves
Long wavelength
Strong swash / weak backwash
Beach gain
Destructive Waves
Short wavelength
Weak swash / strong backwash
Beach loss
Costal erosion Abrasion
Waves advances and picks up sand and pebbles
When pulling away the waves retreat the material
When the wave hits the cliff it chips away
Costal erosion Hydraulic Action
When a wave advances air is trapped and compressed in joints and cracks
Then the wave retreats and compresses the air and expands
This continues process can weaken joints and cracks in the cliff
This causes pieces of rocks to break off
Costal erosion Corrosion
The weak acid in the sea water dissolves always the alkaline rock suck as chalk and limestone
Landforms created by costal erosion
Headlands and bays
Cliffs
Stacks and stumps
Shoreline platform
Longshore drift
Wave approaches beach at an angle
Swash carries material on beach
Backwash carries material down the beach
Backwash is stronger than swash
Sediment cells
Sediment move along the coast
Within each cell the sediment moves between the beach, cliff and sea through the process of erosion
Weathering and mass movement
Freeze-thaw weathering
Water enters the crash or joints
It then freezes and expands
This exerts pressure on the rock
This causes wide crack to form
This process keeps repeating
Slay weathering
When salt water evaporates
Leaves salt crystals behind
Rocks such as clay expand when they are exposed to water
Mass movement (Soil Creep)
Soil creep the slowest form of mass movement
It is the very slow downhill movement of individual soil particles
Earth flows/ mudflows
And increase in water can reduce friction causing earths mud to flow over underlying bedrock
Slumps
Often occur in saturated conditions
Occur on moderate to steep slopes
Slumping causes rotational scars
