Coast

So sorry like SO long never post already. Have been busy with study. However, I back ! :D
For Geography, I guess you can buy guide books then helps you summaries the whole book. Here I'm using Fairfield Book Publishers' Q&A G.C.E 'o' level Elective Geography topic by topic.



It's really great ! :D I'm also using Mrs Lily Lim Notes [used to be Deyi teacher]{also known as Ben's notes} and my personal notes so if there is any mistake, I'm sorry ! :D

Coast
Definition: A coast is the part of the land which meets the sea and interacts with it. It is always changing sue to coastal processes which shapes it constantly.

Coastal erosion

Factors affecting size of wind

Wind Energy

Greater Pressure → Greater Wind speed → Greater wind energy → Larger Waves

Duration Of wind

longer time → bigger waves

Fetch [Distance]

definition:The distance over which winds blow across open water to form waves.
Longer distance→bigger waves

tides & currents as agents of erosion

Tides are daily changes in sea level due to the movement of the moon and the sun.

A coast experience high tide and low tide every 12 hours

Currents are flows of water that move either horizontally or vertically

Types of waves

Constructive waves

→ Swash is stronger then backwash
→ More materials are deposited
→ builds up the coast
→ occurs on gentle sloping coast
→ break gently with little energy

Destructive Waves

→ backwash is strong then swash
→ More materials are removed instead of deposited
→ steeply sloping coast
→ break violently with high energy

how to remember?
Backwash:backward movement of waves [move backwards take away]

Swash: Forward movement of wave [move forward deposit]

Transportation

[ignore the spelling mistake]

Wave approaches the coast at an oblique angle

The swash brings the sediments up onto the coast at an oblique angle

the backwash then carries the sediments back to the sea at a right angle

This is due to the influence of gravity

This produces a zig-zag movement along the shoreline which transport sediments from west to east producing a long shore drift

Landforms

Questions normally starts with: With a well labeled diagram, explain how (insert land form here) is formed

Please do not explain with out diagram

Diagrams are really important and they cost 6 marks or more !

there are 5 land forms. the textbook only wrote 4.

Cliff And shore platform

A cliff is formed when waves repeatedly pound against a rocky coast,

This weakens the rocks, causing line of weakness to form in the rock face

Overtime,the waves erode the coast to cut a notch along the lines of weakness

the notch may be further eroded to form a cave.

The overhanging part of the notch or cave eventually collapses with repeated pounding of the waves .

the part of the coast that is left forms a cliff.

As cliff continue to be eroded by the wave, it retreats inland

over time ,a gently sloping or falt surface called the wave-cut platform is formed

Head land and bay

the coast line consist of parallel bands of hard and soft rock which are perpendicular to the sea

the less resistant rocks gets eroded faster

while the more resistant rocks get eroded more slowly.

As less resistant rocks are constantly being eroded they curve inwards forming bays

The more resistant rocks protrude out forming headlands.

wave refraction[bending of waves] occurs as waves approaches the headland and bay

Wave energy is concentrated on headland causing erosion to occur.

While wave energy weakens and deposit sedments on the bay.

The headlands get eroded back

the bay get more deposition and form beaches

Overtime, the coastline will become a straight line again and the whole process of differential erosion will occur again.

Beaches

A beach is an area on the coast where sediments are accumulated.

These sediments are fine sand,gravel or shingle

The sediments are deposited by waves,tides or current

beaches made up of coarse material tend to be steeper.

this is due to the strong swash that deposit the on the coast

the backwash is unable yo carry them back into the sea

Beaches made up of sand and fine material tend to me gental sloping

Beaches are constantly changing its shape and size.

during stormy days beaches are eroded more quickly due to destructive waves

during clam weathers beaches are build up by constructive waves

spit and tomobolo

Long shore current deposits materials along the coastline where there is shallow and sheltered water.

Material are deposited in the direction of the long shore drift

Overtime, the accumulation of sediments will form a long narrow ridge mainly made of sand

with one end attached to main land and the other extending out to sea.

This is know as a spit

As the spit continue to extend seaward, it may join with an offshore island that is nearby

forming a tombolo

Caves,Arches,Stacks and stumps
# waves attack a crack in a headlands
# This enlarged to form a cave by the pounding of the waves compressing air in the rock face
# and by abrasion where materials carried by water is flung against the cliff
# the cave is made bigger
# if there is one on either side if headlands, an arch will result when they join
# As further erosion takes place, the arc eventually collapse
# the seaward end of the arch will form a stack
# Further erosion takes place and a stump is formed which can only be seen at low tide