Coastal Landforms (Edexcel IGCSE Geography)

Revision Note

Test yourself
Jacque Cartwright

Written by: Jacque Cartwright

Reviewed by: Bridgette Barrett

Erosional Landforms

Headland and bay 

  • Found in areas of alternating bands of resistant (hard) and less resistant (soft) rocks running perpendicular to oncoming waves (discordant coastline)

  • Initially, less resistant rock (e.g. clay) is eroded back, forming a bay

  • A bay is an inlet of the sea where the land curves inwards, usually with a beach

  • The more resistant rock (e.g. limestone) is left protruding out to sea as a headland

headland--bay-formation
Headland and bay formation

Cove

  • A cove forms where the coastline has bands of resistant and less resistant rock running parallel to the oncoming waves (concordant coastline)

  • There is usually a band of resistant rock facing the oncoming waves, with a band of softer rock behind

  • Wave processes of abrasion, corrosion and hydraulic action will exploit faults in the resistant rock and erode through to the softer rock 

  • Further wave action will erode the softer rock quickly, which will leave behind a circular cove with a narrow entrance to the sea

  • Wave refraction within the cove spreads out the erosion in all directions, creating the typical horseshoe shape

  • Lulworth Cove in Dorset, UK, is a good example of a cove

Cove formation
The formation of coves

Cliff and wave-cut platform

  • Cliffs are shaped through erosion and weathering processes

  • Less resistant rock erodes quickly and will form sloping cliff faces

  • Steep cliffs are formed where there is harder rock facing the sea

  • A wave-cut platform is a wide gently sloped surface found at the foot of a cliff:

    • As the sea attacks the base of a cliff between the high and low water mark, a wave-cut notch is formed

    • Abrasion, corrosion and hydraulic action further extend the notch back into the cliff

    • The undercutting of the cliff leads to instability and collapse of the cliff

    • The backwash of the waves, carries away the eroded material, leaving behind a wave-cut platform

    • The process repeats and the cliff continues to retreat, leading to a coastal retreat

cliff-and-wave-cut-platform
The formation of cliffs and wave-cut platforms

Cave, arch, stack and stump

  • Found on a headland due to wave action and sub-aerial weathering

  • Any weaknesses in the headland are exploited by erosional processes of hydraulic action, abrasion and corrosion

  • As the crack begins to widen, abrasion will begin to wear away at the forming cave

  • The cave will become larger and eventually break through the headland to form an arch

  • The base of the arch continually becomes wider and thinner through erosion below and weathering from above

  • Eventually, the roof of the arch collapses, leaving behind an isolated column of rock called a stack

  • The stack is undercut at the base by wave action and sub-aerial weathering above until it collapses to form a stump

Stages of Stack formation
Stack formation

Depositional Landforms

Beach

  • Form in sheltered areas such as bays

  • Deposition occurs through constructive wave movement, where the swash is stronger than the backwash

  • Beach formation usually occurs in the summer months when the weather is calmer

  • Sometimes sand from offshore bars can blow onto the shore by strong winds

  • Blown sand can create sand dunes at the backshore of a beach

Spit

  • An extended stretch of sand or shingle that extends out to sea from the shore

  • Spits occur when there is a change in the shape of the coastline

  • Or the mouth of a river, which prevents a spit from forming across the estuary

  • A spit may or may not have a 'hooked' end, depending on opposing winds and currents

  • A good example is Spurn Point, which stretches for three and a half miles across the Humber Estuary in the northeast of England

Stages of Formation:

  • Sediment is transported by longshore drift

  • Where the coastline changes direction, a shallow, sheltered area allows for deposition of sediment

  • Due to increased friction, more deposition occurs 

  • Eventually, a spit slowly builds up to sea level and extends in length

  • If the wind changes direction, then the wave pattern alters and results in a hooked end

  • The area behind the spit becomes sheltered

  • Silts are deposited here to form salt marshes or mud flats

spit-formation
Spit formation

Bar

  • When a spit grows across a bay, and joins two headlands together

  • A bar of sand is formed (sandbar)

  • Sandbars can also form offshore due to the action of breaking waves from a beach

bar formation
Bar formation

Lagoon

  • A lagoon is where a small body of water is cut off from the sea 

  • A lagoon may form behind a bar or tombolo

  • Lagoons do not last forever and may fill with sediment and form new land

Tombolo  

  • A tombolo is formed when a spit joins the mainland to an island

  • Chesil Beach in Dorset is a tombolo, as the mainland is joined to the Isle of Portland 

Barrier Island

  • Barrier islands form parallel to the coast 

  • The main difference between a bar and barrier island is that a bar joins two headlands, whereas a barrier island is open at one or both ends

Formation of coastal depositional landforms
Deposition landforms

Examiner Tips and Tricks

You may be asked to draw and label a diagram showing how depositional landforms (beaches, spits etc.) are formed. You need to be able to show how sediment is transported along the coast by waves. Practice drawing and labelling these diagrams so you can reproduce any of them in the exam. Marks will be awarded for the accuracy and completeness of your labelling and drawing. 

Last updated:

You've read 0 of your 10 free revision notes

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Jacque Cartwright

Author: Jacque Cartwright

Expertise: Geography Content Creator

Jacque graduated from the Open University with a BSc in Environmental Science and Geography before doing her PGCE with the University of St David’s, Swansea. Teaching is her passion and has taught across a wide range of specifications – GCSE/IGCSE and IB but particularly loves teaching the A-level Geography. For the past 5 years Jacque has been teaching online for international schools, and she knows what is needed to get the top scores on those pesky geography exams.

Bridgette Barrett

Author: Bridgette Barrett

Expertise: Geography Lead

After graduating with a degree in Geography, Bridgette completed a PGCE over 25 years ago. She later gained an MA Learning, Technology and Education from the University of Nottingham focussing on online learning. At a time when the study of geography has never been more important, Bridgette is passionate about creating content which supports students in achieving their potential in geography and builds their confidence.