Unit 8 - Essays - Coastal Landforms Flashcards
(8 cards)
Assess the significance of longshore drift in the formation of depositional landforms.
Assess the significance of longshore drift in the formation of depositional landforms
Paragraph 1 – Spits & Compound Spits (e.g. Spurn Head)
Longshore drift moves sediment along the coast until it extends into open water.
Recurved ends and ridges show ongoing deposition influenced by tidal currents and storms.
Key landform where longshore drift is dominant.
Paragraph 2 – Drift-Aligned Beaches (e.g. West Wittering Beach)
Created by oblique wave approach; material transported parallel to shore.
Deposition occurs down-drift where energy decreases.
Direct correlation between prevailing winds and beach alignment.
Paragraph 3 – Cuspate Forelands (e.g. Dungeness)
Formed by converging longshore drift from opposite directions.
Sediment builds into triangular features, dependent on bi-directional drift.
Paragraph 4 – Tombolos (e.g. St Ninian’s)
Longshore drift contributes to sediment accumulation between island and mainland.
Wave refraction assists but drift supplies material.
Paragraph 5 – Barrier Beaches & Islands (e.g. Slapton Sands, Outer Banks)
Longshore drift reworks sediments over time, forming linear features.
Sea-level rise can amplify this, but drift provides core sediment input.
Conclusion – Judgement
Longshore drift is highly significant in shaping many depositional landforms, particularly linear and coastal-joining features. Other processes like wave refraction and tidal currents are supportive but secondary in these cases.
To what extent is sediment supply the most important factor influencing the characteristics and formation of depositional landforms in coastal environments?
To what extent is sediment supply the most important factor influencing the characteristics and formation of depositional landforms in coastal environments?
Paragraph 1 – Barrier Islands & Beaches (e.g. Outer Banks, Slapton Sands)
Formed by reworked sediments and marine deposition.
Without sufficient sediment, these landforms cannot develop or persist.
Sea-level rise reshapes but doesn’t supply material.
Paragraph 2 – Mudflats & Saltmarshes (e.g. Morecambe Bay, The Wash)
Depend on fine sediment (silt and clay) supplied by rivers and tides.
Flocculation and tidal flows key in creating and stabilising landforms.
Paragraph 3 – Coastal Dunes (e.g. Formby)
Require consistent beach sediment supply for wind transport inland.
Vegetation traps the sediment, but initial availability is crucial.
Paragraph 4 – Role of Marine Processes (e.g. wave refraction, tides)
Wave action, refraction, and constructive waves influence sediment positioning.
These processes shape the form but rely on prior sediment availability.
Paragraph 5 – Human and Climatic Influences
Sediment starvation can occur due to coastal protection structures.
Climate-induced storm activity redistributes existing sediment.
Conclusion – Judgement
Sediment supply is the fundamental prerequisite for depositional landforms; without it, other processes cannot act. It is the most important factor overall.
Assess the relative importance of the factors influencing the formation of coastal saltmarshes and mangroves.
Assess the relative importance of the factors influencing the formation of coastal saltmarshes and mangroves
Paragraph 1 – Sediment Supply and Tidal Deposition
Both environments require low-energy, fine sediment (e.g. The Wash, Sundarbans).
Tidal flows and deposition enable the landform to build up.
Paragraph 2 – Vegetation and Biological Colonisation
Saltmarshes: pioneer plants (eelgrass) trap and stabilise sediment.
Mangroves: dense roots trap sediment and slow water, aiding build-up.
Paragraph 3 – Climate and Temperature
Mangroves need tropical climates (Sundarbans).
Saltmarshes develop in temperate estuaries. Temperature limits range.
Paragraph 4 – Sea Level and Intertidal Zone
Both form in intertidal zones; rising sea level can threaten both.
Mangroves particularly sensitive due to low elevation.
Paragraph 5 – Shelter from Waves and Currents
Sheltered estuaries, deltas, and bays are essential to reduce wave energy.
High energy coasts prevent development of both systems.
Conclusion – Judgement
While all listed factors matter, sediment supply and tidal deposition are the most important shared factors; however, temperature is a key differentiator between saltmarshes and mangroves.
‘Sea-level rise affects coastal depositional landforms more than coastal erosional landforms.’ How far do you agree with this view?
‘Sea-level rise affects coastal depositional landforms more than coastal erosional landforms.’ How far do you agree with this view?
Paragraph 1 – Vulnerability of Low-Lying Depositional Landforms (e.g. Maldives, Mangroves)
Beaches and atolls <2.5m elevation are highly at risk of submergence.
Mangroves and saltmarshes may drown or be squeezed out with rising seas.
Paragraph 2 – Reworking and Retreat of Barrier Features (e.g. Outer Banks)
Sea-level rise causes inland migration and breaching.
Loss of sediment can lead to collapse of systems.
Paragraph 3 – Impact on Erosional Landforms (e.g. Rias and Fjords)
Sea-level rise contributes to formation of rias and fjords via submergence.
Raised beaches may become active cliffs again or be submerged.
Paragraph 4 – Coastal Cliffs and Increased Erosion (e.g. Holderness)
Higher sea levels increase erosion by raising the base level.
Cliffs may retreat faster, but form persists.
Paragraph 5 – Adaptability and Sediment Supply
Some depositional systems can adapt if sediment supply is sufficient.
Erosional landforms are less dynamic and may erode faster but not disappear.
Conclusion – Judgement
Sea-level rise poses a greater threat to depositional landforms due to their low elevation and sediment dependence, though erosional landforms also accelerate in response. Statement is largely accurate.
Evaluate the role of sub-aerial processes in the development of coastal cliffs and wave-cut platforms.
Evaluate the role of sub-aerial processes in the formation of erosional landforms in coastal environments
Paragraph 1 – Role in Cliff Retreat (e.g. Holderness Coast)
Sub-aerial processes like rainwater saturation lead to slumping and rotational slips.
Particularly important in soft rock coastlines (e.g. glacial till at Holderness).
Paragraph 2 – Contribution to Wave-Cut Notch Formation
Weathering (e.g. freeze-thaw, salt crystallisation) weakens cliff face above marine notch.
Aids collapse after wave undercutting, accelerating platform formation.
Paragraph 3 – Interaction with Marine Processes
Sub-aerial processes prepare material for removal by marine erosion.
They don’t directly erode, but make cliffs more vulnerable.
Paragraph 4 – Role in Landform Evolution (e.g. Raised Beaches, Portland)
Weathering continues on relict cliffs after marine action ends.
Processes like biological weathering shape upper cliff faces.
Paragraph 5 – Variation by Geology and Climate
More significant on soft, permeable rocks or in wetter climates.
Less important on hard rock, vertical cliffs with little vegetation or water access.
Conclusion – Judgement
Sub-aerial processes are essential in supporting and accelerating marine erosion but are rarely the dominant force in landform initiation. They are complementary.
Assess the extent to which the characteristics of coastal cliffs are the result of marine processes
Assess the extent to which the characteristics of coastal cliffs are the result of marine processes
Paragraph 1 – Cliff Erosion by Marine Processes (e.g. Holderness)
Hydraulic action and abrasion at cliff base form notches, leading to collapse.
Dominant in areas with high wave energy and soft lithology.
Paragraph 2 – Cliff Profile and Wave Energy
Steep cliffs on rocky coasts result from high-energy, plunging breakers (e.g. California).
Wave type (constructive/destructive) influences erosion rates.
Paragraph 3 – Influence of Sub-Aerial Processes
Weathering and mass movement shape upper cliff profile.
Slumping creates stepped profiles in weaker rocks.
Paragraph 4 – Role of Lithology and Structure
Jointed or permeable rocks (e.g. clay, sandstone) allow water ingress and promote slumping.
Harder rocks (e.g. granite) produce sheer, vertical cliffs with marine dominance.
Paragraph 5 – Tidal Range and Exposure
High tidal range exposes more cliff to erosion.
E.g., UK coasts erode more due to multiple daily tidal cycles.
Conclusion – Judgement
Marine processes are the primary factor in cliff foot erosion and retreat, but cliff shape and structure also depend on sub-aerial processes and geology.
‘Wave energy is the most important factor influencing the formation of erosional landforms in coastal environments.’ How far do you agree?
‘Wave energy is the most important factor influencing the formation of erosional landforms in coastal environments.’ How far do you agree?
Paragraph 1 – Wave Energy and Marine Erosion
High-energy waves (destructive) erode through hydraulic action, abrasion.
Responsible for creating cliffs, platforms, arches, and stacks.
Paragraph 2 – Wave Refraction and Energy Focus
Refraction directs energy to headlands (e.g. Old Harry Rocks), enhancing erosion.
Bays experience energy dispersion and deposition.
Paragraph 3 – Sub-Aerial and Weathering Processes
Not landforms on their own but speed up erosion by weakening structure.
Key in landslides, slumping, especially in saturated or soft cliffs.
Paragraph 4 – Geology and Rock Resistance
Landform type and evolution are constrained by rock type (e.g., discordant coasts).
Differential erosion creates headlands and bays regardless of wave energy.
Paragraph 5 – Sea-Level and Tectonic Activity
Raised beaches and fjords (e.g. Sognefjord) influenced more by post-glacial processes than wave energy.
Wave energy has limited impact here.
Conclusion – Judgement
Wave energy is most important for active erosion (cliffs, platforms, stacks), but other factors (geology, tectonics, sub-aerial processes) are essential in determining form and location. Statement is mostly true but not universally.
Assess the relative importance of the factors influencing the generation and characteristics of waves
Assess the relative importance of the factors influencing the generation and characteristics of waves
Paragraph 1 – Wind Speed and Duration
Faster and longer wind = more energy transferred to waves.
Leads to larger, longer-period waves (e.g. North Sea storms).
Paragraph 2 – Fetch
Longer fetch allows waves to grow larger before landfall.
Atlantic-facing coasts have more powerful waves than enclosed bays.
Paragraph 3 – Wave Refraction and Orientation
Refraction concentrates energy on headlands, disperses in bays.
Orientation to coast affects longshore drift and energy intensity.
Paragraph 4 – Beach Gradient and Breaking Type
Steep slopes = plunging breakers (erosional).
Gentle slopes = spilling breakers (depositional).
Paragraph 5 – Tides, Water Depth, and Obstacles
High tide allows waves to reach cliffs; low tide limits reach.
Offshore features (reefs, islands) can absorb wave energy.
Conclusion – Judgement
Wind (speed, duration) and fetch are most critical for wave generation, while wave orientation, refraction, and beach profile modify characteristics nearshore. All factors interact, but wind and fetch are foundational.
