Marine Process

Question 1

Features of coastal erosion

Answer 1

Cliff, Wave cut platform, caves, arches, stacks, stump, headland and bay
Form by powerful, destructive wave

Question 2

Feature of coastal deposition

Answer 2

Beaches, spits, bars, sand dunes, marsh

Form by more gentle and constructive waves

Question 3

Factors affecting size of the waves

Answer 3

Duration of the wind
Strength of the wind
Fetch - the distance across the ocean that a wind has been blowing on

Question 4

Describe destructive waves

Answer 4

High energy, responsible for eroding the coast
High wave in proportion to length
Transport material away from the beaches
High frequency
Steep, close together
Backwash stronger than swash

Question 5

Describe constructive waves

Answer 5

Strong swash, weaker backwash
Shallow, widely space apart
Low wave in proportion to length
Carry material up the beach creating depositional landform

Question 6

Swash

Answer 6

The movement of water and load up the beach

Question 7

Backwash

Answer 7

The movement of water and load back down the beach

Question 8

Longshore drift

Answer 8

The process of waves moving material and load along a coastline
If the coastline changes direction, material will continue to be deposited in the original direction

Question 9

Prevailing wind

Answer 9

The direction that the wind normally hits a coastline

Question 10

Sand dunes

Answer 10

Very dynamic, constantly changing
Need a large supply of sand
Dry sand being blown up the beach
Sand transported by the wind by saltation
Sand deposited against obstruction
Colonise by small plant, increasing size and trap more sand

Question 11

Cliff, wave cut notch, wave cut platform

Answer 11

Cliff are formed when destructive wave attack the bottom of a rock face
Hydraulic and abrasion undercut the face, forming a wave cut notch - lines of weakness are attacked
Waves continue to attack , the notch increase in size until the weight of the overhanging rock is so great -> it collapses
The loose rock are transported along the coast by longshore drift
The whole process begins again
As the cliff eroded backward, it leaves behind a wave cut platform
This rarely eroded as the wave energy is concentrated on eroding the notch above it

Question 12

Caves, arches and stacks

Answer 12

Waves approach headland -> refracted -> concentrates energy on the headland and disperses energy across bay -> erosion from side of headland
Waves start by attacking line of weakness (joints and fault) by hydraulic
Line of weakness increase in size -> caves form
Cave get bigger -> cut all the way through the headland -> arch form
Continue erosion -> roof collapse because too heavy and weathering and erosion -> leaving an isolated column of rock called stack
Stack eroded by the sea and weather -> reduce size -> stump

Question 13

Bay and headland coastlines

Answer 13

formed when the sea attacks a section of coast with alternating bands of hard and soft rock (discordant)
Bays are formed due to rapid erosion of less resistant rock
Where there is more resistant rock, erosion id slower -> headland form as the harder rock is left sticking out
Once formed, the headland is left more vulnerable to erosion and the waves energy refracted and concentrated here -> shelter bay

Question 14

Bay

Answer 14

An intended area of land normally found between two headland

More shelter -> less erosive power -> find beaches in bays

Question 15

Headland

Answer 15

A piece of land that sticks out into the sea

Waves refract around headland -> experience a lot of erosion

Question 16

Spits form

Answer 16

Longshore drift transport material along the coastline
Formed in areas of relatively shallow and sheltered water where there is a change in the direction of coastline but longshore drift still continue
Deposition occurs resulting in the accumulation of sand and shingle
The material initially deposited is the largest material
The finer material is then deposited, helping to build up the rest pf the spit
Short change in wind direction -> change the direction of spit -> curve end
Salt marsh form in the sheltered, low energy zone behind the spit

Question 17

Bars formation

Answer 17

Form when a spit grows the whole way across a bay
The area between the bar and bay is called lagoon
-> gradually be infilled with deposition

Question 18

Tombolos form

Answer 18

Forms when spit continues to grow outwards connecting the mainland to the offshore island just like bridges

Question 19

Define spit

Answer 19

A sand ridge, usually curving, that is joined to the land at one end and just out into the sea at the others

Question 20

Define bar

Answer 20

A ridge of sand and shingle which has joined two headland, cutting off a bay

Question 21

Define tombolos

Answer 21

A ridge of sand and shingle joining the mainland to an island

Question 22

Condition for coral to grow

Answer 22

Warm water, > 18, grow best between 23 -25 - tropical sea conditions, between two tropics
Clear, no sediment, shallow water, no deeper than 60m - no pollution
Oxygen
Plenty of sunlight for photosynthesi

Question 23

Benefits

Answer 23

Employment, seafood
Protect shorelines and communities from storms and erosion - can absorb energy
Natural recycle agent for co2 from sea and atmosphere
Contribute material to the formation of beaches (eroded coral reef)
Source of raw material (coral for jewelry and ornaments)
Tourism - dive and snorkels

Question 24

Describe fringing reef

Answer 24

Grow out to the sea attached to the mainland, circle the coast line
Often protected by barrier reef further out to the sea -> plant and animal suited to low wave energy environment

Question 25

Barrier reef

Answer 25

Occur further from the sea and are commonly separated from the mainland or island by a deep lagoon Older and wider than fringing reef

Question 26

Atoll

Answer 26

A ring of coral reef with a lagoon replacing the island in the centre

Question 27

What is coastline

Answer 27

The border between the land and the sea