Coasts EQ1 Flashcards
What is the littoral zone?
The littoral zone is the area of shoreline where land is subject to wave action.
It’s subdivided into offshore, nearshore, foreshore and backshore. (ONFB - OKAY NOW FRY BANANAS!)
What is an emergent coastline?
Land is rising relative to sea levels.
(due to tectonic uplift or sea levels falling).
What is the 5 criterea used to classify a coast
- Geology - Rocky or sandy coastlines / concordant or discordant coastlines.
- Wave energy - High or Low energy enviroments
- Relative sea level change - create either emergent or submergent coastlines.
- Formation processes - primary or secondary coastlines
- Tidal range
What is a submergent coastline?
Where sea levels are rising relative to the land / land is sinking.
Cornwall
What is deformation
Deformation 🔄 – When rocks bend or change shape due to pressure from tectonic activity.
Describe a high energy coastline
High-Energy Coasts 🌊⚡ More erosion than deposition
Strong waves, heavy erosion
Found on open coastlines
Rocky cliffs, pebbles, and few sediments
Erosion & transportation
Cliffs - Wave Cut platforms- Sea caves - CASS
Describe a low energy coastline?
Low-Energy Coasts 🌊➡️ More deposition than erosion
Gentle waves, little erosion
Found in bays, estuaries, and lagoons
Builds up sand and mud (deposition)
LSD & currents
Beaches - spits - sand dunes - salt marshes - bars
What is faulting
Faulting ⚡ – When rocks break and move along a crack (fault) due to stress.
What is “Strata”
Strata 🏔️ – Layers of rock or sediment stacked over time.
What is a concordant coastline?
Bands of hard and soft rock are parallel to the coastline which forms a coast of high cliffs and small caves/coves. Only one type of rock is touching the water unless it gets eroded back into coves.
LULWORTH COVE
What is a discordant coastline?
Both hard and soft rock alternate facing the ocean (right angle) - soft rock erodes easy creating bays and headlands.
DORSET.
What is wave refraction (use discordant coast as an example)
This creates wave refraction as headlands absord powerful wave energy and create lower, diverging waves for the softer rock bays. Also water near the headland is shallower so waves slow down and height increases forcing them to crash at headlands.
What is a HAFF coastline
These form where deposition produces unconsolidated geological structures parallel to the coastline. Long sediment ridges run parallel to the coast - just offshore creaing lagoons (haffs) between ridges and shore.
It is like a very long barrier beach.
I.E Gdansk Poland Haff coastline.
Concordant
What are Dalmatian coastlines?
Formed due to rising sea levels - valleys and ridges run parallel to each other (discordant). As valleys flooded - the tops of ridges remained above sea level - creating a series of offshore islands parallel to the coast.
I.E COAST OF CROATIA.
Concordant
What are cliff profiles and how do they influence the shape of the coast?
A cliff profile refers to the height, steepness, and shape of a cliff, influenced by rock type, structure, and coastal processes.
- Rock Type: Hard rock (e.g., granite) forms steep, slow-eroding cliffs, while soft rock (e.g., clay) creates gentle, fast-eroding slopes.
- Strata Orientation: Horizontal layers form strong, vertical cliffs; seaward dips lead to unstable, slumping cliffs; landward dips create stable, steep cliffs.
- Wave Action & Weathering: High-energy waves erode cliffs, forming wave-cut notches, while weathering weakens them, causing collapse.
- Mass Movement: Weak rock leads to slumping, shaping coastlines, while resistant cliffs erode at the base and retreat slowly.
What are faults
Fractures in the rock.
What are geological dips
The angle which rock strata lie
What is LITHOLOGY
The physical characteristics of particular rocks.
What are cliff micro features?
Micro-features are small-scale coastal features such as caves and wave-cut notches which form part of a cliff profile.
How can Strata influence cliff profiles?
Rock Type: Harder rocks form steeper cliffs; softer rocks form gentler slopes.
Dip of Strata: Steeply tilted layers create steep cliffs; gently tilted layers form sloping cliffs.
Faulting & Folding: Tectonic activity can create uneven, rugged profiles.
Joints & Fractures: Natural fractures lead to more jagged, irregular cliffs.
What is Igenous Rock?
HIGHLY resistant - Granite / Basalt form rugged vertical cliffs
What is a metamorphic rock?
Metamorphic rock is rock that has been changed from its original form by heat, pressure, or chemical processes deep within the Earth.
They erode slow - Slate, Marble.
What is sedimentary rock?
Limestone, sandstone, shale
lots of fractures - erode moderate - fast.
What is the effect of permability on rates of coastal recession?
Permeable rocks allow water to pass through the rock via spaces and pores. They are often more vulnerable to freeze thaw weathering.
Water flowing through them can also remove the cement that binds sediment in then rock together.
Water emergening at a joint between a permeable rock (sandstone) and an impermeable layer (clay) can cause surface runoff eroision and instability causing slipping or slumping.
What are salt marshes?
Coastal wetlands that are flooded and drained by salt water brought in by the tides.
What conditions are required to form salt marshes?
Low tidal energy
Limited erosion
Shelter from wind and waves
Large input of sediment from rivers and sea.
estuarine areas
How do dunes form?
- Sediment Supply – Sand is transported by waves and wind.
- Wind Transport – Onshore winds move sand inland via saltation.
- Obstacle Formation – Sand accumulates around obstacles (e.g., driftwood, rocks).
- Vegetation Growth – Pioneer plants (e.g., marram grass) trap sand and stabilise dunes.
- Dune Succession – Dunes develop from embryo dunes to mature dunes with full vegetation cover.
What are Swash Alinged beaches?
When waves break parallel with the coast, movement of water and material is largely up the beach. This leads to formations of:
Tombolos, barrier beaches, Bars etc.
What are drift aligned beaches?
A drift-aligned beach is a type of beach that forms parallel to the direction of longshore drift.
Spits, recurved spits, cuspate forelands.
What are Cuspate Forelands?
Little triangle shaped features.
