The document discusses coastal landforms, categorizing them as depositional (e.g., beaches, spits, tombolos) or erosional (e.g., cliffs, caves). It explains the formation processes of these landforms, including how beaches are built up by constructive waves, and how cliffs are shaped by erosion and weathering. The document details specific coastal features and processes such as longshore drift, headland formation, and the evolution of caves into arches and stacks.

1. YEAR 10 GEOGRAPHY
COASTS
10. COASTAL LANDFORMS

2. Coastal landforms can be either depositional or erosional.
Beaches, spits and tombolos are examples of depositional
landforms.
Cliffs and caves are examples of erosional landforms.

3. Beaches are a common feature of a coastline.
Beaches are made up of eroded material that has been
transported from elsewhere and deposited by the sea.
Constructive waves help to build up beaches.
A cross-section of a beach is called a beach profile.
The shingle ridges often found towards the back of a beach are
called berms.

4. A beach showing berms

5. An example of a pure gravel beach, Canterbury Bight, New Zealand. Gravel
dominates from the top of the storm berm to below the low-tide mark

6. Most waves break near the shoreline, so sediment near the
water is more effectively broken down by attrition.
Sandy beaches have gently sloping profiles and shingle and
pebble beaches are steeper.

7. A pebble beach with a steep profile

8. Spits are also created by deposition.
Spits are formed where the prevailing wind blows at an angle
to the coastline, resulting in longshore drift.

9. The development of Spurn Head

10. Longshore drift moves material along the coastline.
A spit forms when the material is deposited.
Over time, the spit grows and develops a hook if wind direction
changes further out.
Waves cannot get past a spit, which creates a sheltered area
where silt is deposited and mud flats or salt marshes form.

12. A tombolo is a spit connecting an island to the mainland.
Lagoons have formed behind the stretch of beach material.

13. Punta Uvita Tombolo, Costa Rica

14. One of the most common features of a coastline is a cliff.
Cliffs are shaped through a combination of erosion and
weathering - the breakdown of rocks caused by weather
conditions.
Soft rock, eg sand and clay, erodes easily to create gently
sloping cliffs.
Hard rock, eg chalk, is more resistant and erodes slowly to
create steep cliffs.

15. Seven Sisters chalk cliffs on the East Sussex coast

17. Weather weakens the top of the cliff.
The sea attacks the base of the cliff forming a wave-cut notch.
The notch increases in size causing the cliff to collapse.
The backwash carries the rubble towards the sea forming a
wave-cut platform.
The process repeats and the cliff continues to retreat.

18. Headlands are formed when the sea attacks a section of coast
with alternating bands of hard and soft rock.
The bands of soft rock, such as sand and clay, erode more
quickly than those of more resistant rock, such as chalk.
This leaves a section of land jutting out into the sea called a
headland.
The areas where the soft rock has eroded away, next to the
headland, are called bays.

19. Bay and headland in New Zealand

20. Weathering and erosion can create caves, arches, stacks and
stumps along a headland.

22. Caves occur when waves force their way into cracks in the cliff
face.
The water contains sand and other materials that grind away at
the rock until the cracks become a cave.
Hydraulic action is the predominant process.
If the cave is formed in a headland, it may eventually break
through to the other side forming an arch.

23. The arch will gradually become bigger until it can no longer
support the top of the arch.
When the arch collapses, it leaves the headland on one side and
a stack (a tall column of rock) on the other.
The stack will be attacked at the base in the same way that a
wave-cut notch is formed.
This weakens the structure and it will eventually collapse to
form a stump.
One of the best examples in Britain is Old Harry Rocks, a stack
found off a headland in the Isle of Purbeck.