4. UK Evolving Physical Landscape: Coastal Landforms Flashcards
What are the 2 types of Coastline?
Concordant
Discordant
Geological structure influences formation of erosion along landforms
Hard rock - more resistant - longer to erode
Soft rock - less resistant - eroded more quickly
Joints faults and cracks are weaknesses and erode faster
What is a Concordant Coastline?
Alternating bands of hard and soft rock - parallel to coast
Eroded at same rate along the coast - fewer erosion along landforms
What is a Discordant Coastline?
Alternating bands of hard and soft rock - perpendicular to the coast
Headlands and bays are common - bands of rock eroded at different rates
How has the UK climate impacted Coastal Erosion and Retreat?
Temp varies with seasons - differences impact processes along coast e.g. mild increases the rate of salt weathering
Winter storms - strong winds - high energy - destructive waves - erosion of cliffs
Intense rainfall - cliff saturated - mass movement
Most common wind - warm south westerly - storm from Atlantic - south coast exposed
Cold motherly winds common on East coast
What is the effect of Destructive Waves?
Erosion processes
Waves high frequency and steep
Backwash more powerful than swash - material removed from coast - coastal retreat
What is formed when waves erode Cliffs?
Wave cut platforms
Most erosion at foot of cliff - wave cut notch - rock above unstable and collapses - collapses material is washed away
Repeated collapsing - cliff retreating - wave cut platform left behind
What forms along Discordant Coastlines?
Headlands and bays
Soft rocks - lots of joints - low resistance to erosion - hard rocks high resistance
Headlands and bays - alternative bands of resistance and less resistant bands across the coast
Bay - gentle slope
Headland - steep slope - resistant rock erodes slowly - left jutting out
What are the 3 things formed when Headlands are eroded?
Caves
Arches
Stacks
Resistant rock - cracks - weak - waves enlarge by hydraulic power - causes caves to form
Deep erosion of cave break through to form an arch
Further erosion - wears away supporting arch - collapses - stack
What is Transportation?
Movement of material resultant from erosion
Material transported along coats - longshore drift
Waves direction of prevailing wind - hit coast at an oblique angle
Swash - material up beach
Backwash - material down beach at right angles
Material zig zags along coast
What is the effect of Constructive Waves?
Deposit Material - water slow down and leaves sediment
Leave more material than remove - Constructive
Constructive waves - long, low frequency - 6-8 per min
Swash powerful - Backwash less power full
Deposit sand and shingle along coast from beach
What does Deposited Sediment form?
Spits and Bars
What is a Spit?
Spit - sharp bend in coastline e.g river mouth - longshore drift - sand and shingles past bend an deposit in sea - sheltered area behind spit protected from waves
What is a Bar?
Bar - forms when a spit joins 2 headlands together - cuts off bay from the sea - lagoon can form
How do you identify Coastal landforms caused by Erosion?
Determine if there are bays, headlands, caves, arches, stacks, cliff platforms etc
How do you identify Coastal landforms caused by Deposition?
Beaches shown in yellow; shingle beaches as white / yellow with speckles
Spit by beach - out to sea and attached to land at one end - sharp bend in coast
