Coasts Flashcards
What are the three types of weathering and what doe they do?
Mechanical:the disintegration of rock(Freeze thaw, water collects in rocks and freezes expands cracks and more water goes deeper in process repeats)
Chemical:caused by chemical changes(rainwater absorbs CO2 causing it to become slightly acidic)
Biological:caused by actions of flora and fauna(roots grow in cracks)
Types of mass movement
Rockfall-rock breaks away often due to freeze thaw
Landslide-blocks of rock slide downhill
Mudflow-saturated soil and weak rock flows downhill
Rotational slip-slump of saturated soil and weak rock along a curved surface
The 5 processes of coastal erosion
Solution-Dissolving of soluble chemicals in rock
Corrasion-rock fragments picked up by sea and thrown at cliff scraping and wearing rock away
Abrasion-sandpapering effect of pebbles grinding over a rocky platform
Attrition-rock fragments carried by sea knock against each other becoming more smaller and rounded
Hydraulic power-power of waves as they hit a cliff, trapped air forced into cracks in rock eventually causing them to break up
Depositional landforms that occur when waves lose their energy
Beaches:Process: Sediment is deposited by waves and currents along the shore.
Key factors: Wave action, longshore drift, and tidal movement.
Mudflats:Process: Fine sediments (mud and silt) are deposited in sheltered, low-energy areas like estuaries.
Key factors: Slow-moving water and tidal action.
Saltmarshes:Process: Mud and organic material accumulate in coastal areas where salt-tolerant plants grow, forming wetlands.
Key factors: Deposition of sediment and plant colonization.
Sheltered estuaries:Process: Freshwater from rivers meets seawater, leading to sediment deposition and mixing.
Key factors: River flow, tidal action, and deposition of silt and clay.
Spits:Process: Sand is transported by longshore drift and deposited where the coastline changes direction, forming a narrow landform.
Key factors: Longshore drift and changes in wave direction.
Transport of sediment
Solution-dissolved chemicals often derived from limestone and chalk
Suspension-particles suspended within the water
Traction-Large pebbles rolled along the seabed
Saltation-Bouncing motion of particles too heavy to be suspended
Caves, arches and stacks
1.Lines of weakness in resistant rock vulnerable to erosion
2.Abrasion and hydraulic action widen the joint or fault forming a cave
3.Erosion may lead to two back to back caves breaking through a headland to form an arch
4.Arch enlarged by erosion and roof is attacked by weathering processes and eventually collapses
5.Leaves behind an isolated stack
6.Stack is eroded and collapses, leaving behind a stump
Swanage location and significance
Dorset, lies on the south coast of England, has concordant coastline forms where different rock types run parallel to the coast, so coast is mainly formed of one type.
Hard engineering examples,cost advantages and disadvantages
Sea walls-concrete or rock barrier at the foot of cliffs or top of beach, curved to reflect waves out to the sea.£5,000-£10,000 per metre,advantages-effective and creates a walkway;disadvantages-obtrusive and unnatural, expensive high maintenance costs
Soft engineering examples,cost advantages and disadvantages
Beach nourishment-sand or shingle is dredged offshore and transported to the coast by barge, dumped on beach and shaped by bulldozers creating a wider, higher beach known as re-profiling, protecting land and property.£500,000 per 100 metre, advantages-blends in with existing beach and bigger beach-more tourists, disadvantage-needs constant maintenance and is expensive
