Crowded Coasts 2.3.1 Flashcards
Enquiry Question: What is the coastal zone and how is it influenced by geology and marine processes
What is the littoral zone, and why is it considered dynamic?
The littoral zone is the coastal area exposed to wave action. It is dynamic because it’s constantly shaped by tides, storms, and sea level change.
Name three short-term factors that influence the littoral zone
Tides, storm surges, and wave energy.
What long-term changes affect the littoral zone?
Sea level rise, isostatic and eustatic changes, and climate change.
How can coasts be classified based on energy?
As high-energy or low-energy coasts depending on wave power and sediment transport.
What is the difference between high-energy and low-energy coasts?
High-energy coasts have strong destructive waves and erosion; low-energy coasts have gentle constructive waves and deposition.
How does sediment type influence coastal classification?
Sandy coasts tend to be depositional; rocky coasts face more erosion.
How can changes in sea level affect coastal classification?
Rising sea levels submerge land (submergent coastlines); falling sea levels expose it (emergent coastlines).
How does relief affect the appearance and processes on a coastline?
Steeper relief leads to cliffs and erosional features; flatter relief allows deposition.
What is geological structure in relation to coasts?
Geological structure refers to the arrangement and orientation of rock layers and faults.
What are concordant coastlines, and how do they form?
A concordant coast has rock layers parallel to the shore, with similar erosion resistance along the coast.
What are discordant coastlines, and how do they form?
A discordant coast has rock layers perpendicular to the coast, creating alternating headlands and bays
Give an example of a landform formed on a concordant coast.
Dalmatian coasts, where flooded valleys create parallel islands.
Explain how headlands and bays form on a discordant coast.
Soft rock erodes to form bays; hard rock remains as headlands.
What is wave refraction and how does it affect discordant coastlines?
Waves bend around headlands, concentrating erosion on headlands and deposition in bays.
How does geological structure influence coastal morphology?
It affects the shape of the coast, cliff height, and erosion resistance.
What role does strata dip play in cliff profile development?
A steep seaward dip creates steep cliffs; landward dip results in more stable cliffs.
How do faults and joints in rock affect erosion rates?
More joints and faults mean more pathways for erosion, increasing rates.
Define what is meant by a composite cliff.
A cliff with layers of different rock types, each with different erosion resistance.
What is the impact of horizontal strata on cliff profiles?
They form flat-topped, steep cliffs.
How do folds and tilting of rock layers influence cliff shape?
Tilted strata create stepped or sloped cliff profiles.
How does differential erosion contribute to complex cliff profiles?
Harder layers erode slowly; softer ones erode faster, creating overhangs, notches, and caves.
What is differential erosion?
It’s when different rock types erode at different rates.
Why do alternating layers of hard and soft rock affect recession rates?
Faster erosion of softer layers leads to cliff retreat and unique formations.
How do micro-features like caves and blowholes relate to geology?
Caves form where weaknesses in rock (faults or joints) are exploited by erosion.
