1. Coastlines: oceanic borders
G.Burgess
2009.

2. Dynamic environment
Zone where, ocean waters meet continental margins and the atmosphere
Marked by beaches, rocky shores, cliffs, etc.
Constantly changing shape and form

3. Erosion
Erosion is destructive waves wearing away the coast. There are four main processes which cause coastal erosion. These are corrasion/abrasion, hydraulic action, attrition and corrosion/solution.
Corrasion/abrasion
When waves pick up beach material (e.g. pebbles) and hurl them at the base of a cliff. (physical action)
hydraulic action
When waves hit the base of a cliff air is compressed into cracks. When the wave retreats the air rushes out of the gap. Often this causes cliff material to break away.
Attrition
when waves cause rocks and pebbles to bump into each other and break up.
Corrosion/solution
when certain types of cliff erode as a result of weak acids in the sea. (chemical action)

4. Transportation
Transportation is the movement of material in the sea and along the coast by waves.
Longshore Drift
movement of material along the shore by wave action.
happens when waves moves towards the coast at an angle.
The swash (waves moving up the beach) carries material up and along the beach. The backwash carries material back down the beach at right angles. This is the result of gravity. This process slowly moves material along the beach.
longshore drift provides a link between erosion and deposition. Material in one place is eroded, transported then deposited elsewhere.

5. Transportation material moves in four different ways; Traction
large material is rolled along the sea floor.
Saltation
beach material is bounced along the sea floor.
Suspension
beach material is suspended and carried by the waves. .
Solution
material is dissolved and carried by the water.

6. Deposition Deposition
when eroded material is dropped by constructive waves.
happens when the wave loses energy and is not able to carry the suspended materials
Helps to sort materials by size
Heavy materials (large rocks) drop first and lighter materials (sand/silt) drop last.
Deposition creates a range of landforms.

7. Nova Scotia Beaches Act, 1989.
The beach is the area between the lowest spring tide level and the point reached by the storm waves in the highest tides.
Every beach is different but they are usually made up of material deposited on a wave-cut platform.
Sand Dunes
created by strong winds (not by coastal erosion or deposition)
sand is blown up a beach forming small hills.
as depression and hills are formed, more sand gets trapped until there is enough that plants may take root.
Dunes are held together by long-rooted grasses such as marram grass. The root systems hold the grains of sand so that they cannot be blown away
Root systems enable the collection of moisture that enables the growth of other plants and development of new food webs

8. Spit Longshore drift moves material along a coastline.
Where there is an obstruction or the power of the waves is reduced the material is deposited.
Where rivers or estuaries meet the sea deposition often occurs.
over the years materials build up forming a long ridge of material, called a spit.
Salt Marshes
A salt marsh is a coastal marsh that forms on mud flats.
They usually form in very sheltered inlets and estuaries, or behind spits (places where fine sediment accumulates).
form as vegetation builds up on mud flats .

9. Sand Bar Waves transport sand making a trough
This forms a division that separates how materials are deposited
Material in backwash is deposited on sand bar and the rest is deposited on the beach

10. Bays, inlets Usually formed by erosion and
transportation of materials.
Wave action will transport the soft rock or sediment to other locations
Factors of transport; storm surges, glaciation (melt and movement of ice during ice age)
Narrow bay = fjiord
Large bay = gulf
Small rounded inlet = cove
Headland (Cape Breton Island): raised area protruding out into the ocean.

11. Human Influences Breakwater
Atlantic Canada relieved as hurricane Bill blows by
Breakwater
An artificial structure of a durable material that interrupts the progress of waves to shore.
used to dissipate some of the oceans wave energy
can be made of a build up of rocks, cement, timbers, boulders, etc.
usually found at the mouth of a harbour to protect the area on the other side of the breakwater

12. What do Breakwaters do?
interrupt the wave energy heading to the beach, weakening the longshore current and allowing sand to accumulate
eventually causes the sand of the beach to approach the breakwater; filling in the area the breakwater is designed to protect the coastline properties.
Also, it may cause erosion further down the coast because of the diverted energy

13. Human Influences (continued)
Groin
A structure extending from the beach into the water.
help to trap sand from the current, accumulating sand on the updrift side.
Usually make erosion worse on the downdrift side where the beach is sand deprived

14. Human Influences (continued)
Souris homes threatened by cliff erosion
Sea Wall
A wall constructed of a durable substance that protects the beach or shoreline from eroding.
the protection is usually temporary because the sea wall is only as good as the substrate it is made of.
they can increase beach erosion because they are deflecting wave energy.
Also, high waves can crash over the wall and erode both sides