Coasts

Question 1

What is a beach and how is it formed

Answer 1

A beach is an accumulation of sand and shingle formed by deposition and shaped by transportation, deposition and erosion.
It forms from accumulation of material,
Sand pebbles and shingle come from different sources
Materials eroded elsewhere are also deposited along the coastline by longshore drift.
Waves sometimes pick up material from the sea bed and roll them towards the beach
It forms in sheltered areas so in bays and is usually protected by two headlands

Question 2

Caves arches stacks and stumps

Answer 2

Lines of weaknesses such as faults occur in headlands and get eroded by hydraulic action and abrasion. Soon a cave widens and then the sea erodes it and sooner cuts through to from and arch, then the foot of it will erode and the roof will become tok heavy and collapse. Part of the former cliff is now isolated as a stack
Now the sea will keep eroding it and it will become undercut and collapse, the remainings of the stack is now a stump

Question 3

What is long shore drift

Answer 3

Long shore drift is the movement of sediments along the coast line

Question 4

What are

1) bars
2) lagoons
3) tambolos

Answer 4

Bars are ridges of sand and other material that run roughly to the coast
Lagoons is water dammed up behind a bar
Tambolos are ridges of sand and other material that connect the mainland to an island a little out to sea

Question 5

What are concordant and discordant coasts and an example

Answer 5

Discordant- an alternating coastline

Concordant parallel to the coastline and the same type of rock all along

Question 6

Erosion

Answer 6

Hydraulic action
Attrition
Abrasion
Corrosion

Question 7

Wave cut notch and wave cut platform

Answer 7

Waves attack the base of the cliff through hydraulic action corrosion and abrasion.
Over time the Cliff becomes undercut and a wave cut notch forms
Eventually the cliff will become unstable and collapse
Further cliff retreat will form a wave cut platform

Question 8

How are spits formed?

Answer 8

Spits are formed when sediments are deposited by longshore drift where the coastline changes direction or where theres an estuary near by.
In Order for them to form they need shallow water for the sediments to deposit easily and they need enough sediments
Where theres a temporary change in wind direction it will form a hook

Question 9

Sunderbans Bangladesh

Answer 9

For them to grow they need a soft muddy shore, for them to take root.
Shorelines also need to be undisturbed for them to do well.
They’re of many benefits
1) fish nurseries
2) a habitat for biodiversity
3) they soak up wave energy which is a benefit for low lying coasts
4) protect coastal areas from storm surges
However now they’re being cleared to provide farmland and timber and fuel.
But Bangladesh realizes that they are very important.
So, as part of the coastal zone policy since they trap silt and stabilize shores, they’ve been planing mangroves in the delta sediments and have gained an extra 120,000 hectares of land As a result.
This was helped by the suburban’s gaining world heritage status in 1998 which allows funds to flow in to protect the area