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RM ACCOUNTS ED
Geography notes
CSEC
rm accounts ed ram@2013
Coasts
Waves rm accounts ed ram@2013
Wave Formation
Frictional force between the wind and the
sea surface
Transfers circular motion to the water
In open water we get swells
As swells approach the shore waves are
formed
Waves break when the depth of the
water is less than the wave height
rm accounts ed ram@2013
rm accounts ed ram@2013
rm accounts ed ram@2013
Type of waves
Two types
Constructive – These build beaches by depositing sand, shingles and pebbles
Destructive – These remove material from the shore
rm accounts ed ram@2013
Destructive Waves These plunge against the shore
rm accounts ed ram@2013
Characteristics - destructive
Backwash is greater than the swash
Backwash > Swash
> 9 per minute
Short wave lengths
Plunge against the shore
rm accounts ed ram@2013
Constructive Waves
These spill onto the shore
rm accounts ed ram@2013
Characteristics - constructive
Swash is greater than the Backwash
Swash > Backwash
< 9 waves per minute
long wave lengths
Spill onto the shore
rm accounts ed ram@2013
Coasts Wave Processes
rm accounts ed ram@2013
Wave Processes
Erode
Transport
Deposit
rm accounts ed ram@2013
Wave Erosion Hydraulic Action – force of the water
alone
Attrition – Load knock against each other
Abrasion or Corrasion – Load erodes the shore
Solution – Sea water disolves minerals in the rock
rm accounts ed ram@2013
rm accounts ed ram@2013
Wave Transportation
The movement of material can be either
of three ways: in, out and along
In, deposition of material to form beaches
Out, removal of material from the shore out
to sea by the undertow
Along the shore is called longshore drift
rm accounts ed ram@2013
Longshore Drift
rm accounts ed ram@2013
The effect of Groynes /
Groines along a beach
rm accounts ed ram@2013
Wave Deposition
Deposition is the laying down of
transported material
Constructive waves and gently sloping
shorelines are associated with deposition
Where rivers discharge into the sea
rm accounts ed ram@2013
Coasts
Coastal Features
rm accounts ed ram@2013
Types of Coastal features
Erosional – those produced by erosion
Examples: cliff, notch, wave-cut platform, headland and bay, caves, arches, stacks and blowholes
Depositional – those produced by deposition
Examples: beaches, spit, tombolo and bars
rm accounts ed ram@2013
Cliff, Notch and Wave-cut
Platform
rm accounts ed ram@2013
Headland and Bay
rm accounts ed ram@2013
deposition
erosion
rm accounts ed ram@2013
Headland and Bay cont’d
rm accounts ed ram@2013
What happens next?
rm accounts ed ram@2013
Wave Refraction
The change in the direction of the waves as they approach the shore, converging on headlands and diverging as they approach the bay
Stronger on the headlands
Weaker in the bay
rm accounts ed ram@2013
rm accounts ed ram@2013
rm accounts ed ram@2013
rm accounts ed ram@2013
rm accounts ed ram@2013
Depositional Features
What are the two main conditions which
lead to the formation of depositional
features?
Constructive waves and gently sloping
shorelines are associated with deposition
Where rivers discharge into the sea
rm accounts ed ram@2013
rm accounts ed ram@2013
A Beach
A beach is a depositional feature. What
material is laid down to form a beach?
What is a bay-head beach?
Draw a diagram to illustrate a beach.
rm accounts ed ram@2013
Other Depositional features
Spit
Bar
Tombolo
Draw well labelled diagrams of the
features identified above.
rm accounts ed ram@2013
Borrowed from: http://imgcdn.geocaching.com/cache/large/23a79aff-4609-43ed-a383-011910ee6680.jpg
rm accounts ed ram@2013
A Spit
rm accounts ed ram@2013
A Tombolo
rm accounts ed ram@2013
A Bar – Baymouth Bar
rm accounts ed ram@2013
Borrowed from: greenfieldgeography.wikispaces.com -
rm accounts ed ram@2013
rm accounts ed ram@2013
A Bar – Offshore Bar
rm accounts ed ram@2013
thanks
Physical Geography in Diagrams
– R B Bunnett
Dale Franklin – for the teaching concepts
and the initial powe-rpoint.
rm accounts ed ram@2013
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