Coasts Revision

Question 1

What is a concordant coastline?

Answer 1

Question 2

How are metamorphic rocks formed? Name some examples

Answer 2

Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means “change in form”.

The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (100 megapascals (1,000 bar) or more), causing profound physical or chemical change.

Quartzite and slate are types of metamorphic rock

Question 3

What is isostaic sea level change?

Answer 3

Isostatic sea level change is the result of an increase or decrease in the height of the land. When the height of the land increases, the sea level falls and when the height of the land decreases the sea level rises. This could happen from tectonic movements

Isostatic change is a local sea level change whereas eustatic change is a global sea level change

Question 4

What distinctive landforms are created by mass movement?

Answer 4

Rotational scars, talus scree slopes, terraced cliff profiles

Question 5

Describe what we mean by a fault in a cliff

Answer 5

Describe the faults in the image below

Question 6

What is an emergent coastline?

Answer 6

An emergent coastline is a stretch along the coast that has been exposed by the sea by a relative fall in sea levels by either isostasy or eustasy

The emergent coastline may have several specific landforms:

Raised beach

Wave cut platform

Question 7

What is a sediment cell?

Answer 7

A sediment cell is a largely self-contained stretch of coastline. They are regarded as closed systems as sedimentis not usually transferred from one to the other. In reality, somesediment does get transferred between neighbouring cells. Each sediment major cell typically has many smaller sub-cells.

Question 8

Name the different inputs into a coastal system

Answer 8

_{Marine – waves, tides and currents<br></br>Energy – kinetic energy from waves and wind, thermal energy from the sun and potential energy from material on cliffs/slopes and material from processes of weathering, mass movement, erosion and deposition<br></br>Geological – rock type, structure and tectonics. material from marine deposition, weathering and mass movement<br></br>Atmospheric – climate, weather and climate change<br></br>People – urban planning, housing, industry, coastal management/defences, leisure}

Question 9

What are coastal plains?

Answer 9

A coastal plain is flat, low-lying land adjacent to a sea coast

Question 10

What is a ria?

Answer 10

A ria is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea.

Question 11

Where is the Haff coastline and what are its distinctive characteristics?

Answer 11

The Haff coastline is the low and regular coastline found in Eastern Germany. It is formed of soft sediments and the sandy strips run parallel to the coast.

The term haff is also used more widely to describe a lowland coast where the long bars and lagoons are parallel to the shore

Question 12

Explain the influence of dip on cliff profiles

Answer 12

• the dip of a rock layer is the angle of tilt from the horizontal.
• if a rock layer dips towards sea the blocks of rock may slide under the influence of gravity (mass movement)
• if the angle of the dip is landward, weathering and erosion may attack exposed bedding planes and joints, creating an irregular profile

Question 13

Describe how the differential erosion of alternating and contrasting rocks affects the coastline

Answer 13

• sedimentary rocks are permeable whereas metamorphic rocks are impermeable.
• the presence of water in these rocks can affect weathering and mass movement e.g. Slumping due to saturation
• some rocks such as limestone contain soluble minerals and so are vulnerable to chemical weathering such as carbonation (sea water absorbs co2 which splashes onto limestone and dissolves it)

Question 14

Explain why estuaries are ideal for the development of salt marshes

Answer 14

• estuaries are low energy environments where tidal conditions bring seawater and sediments in and out and rivers bring fine MUDs and silts and deposit them at the estuary
• the clay particles sick to one another (flocculation) and once deposited are colonised by algae.
• salt marshes can then be found at the edges of estuaries.

Question 15

Explain the formation of embryo dunes

Answer 15

• sand dunes form where there is a plentiful supply of sand and a large area for it to dry out.
• onshore winds blow sand towards land and obstacles such as vegetation and shingle ridges which trap the sand
• embryo dunes are formed first.

Question 16

Why is marram grass so important to the formation of sand dunes

Answer 16

• able to colonise the stable dunes and help hold the sand together and trap more sand.

Question 17

Distinguish between constructive waves and destructive waves

Answer 17

• constructive, larger swash than backwash, build up the beach
• destructive strong backwash weak swash, remove sediment

Question 18

Name and describe the 4 sediment transportation processes

Answer 18

• suspension, small particles carried in the water e.g. Silts and clay, currents pick up large amounts during a storm.
• solution, minerals are dissolved in sea water and carried in solution, load comes from cliffs made form chalk/limestone.
• saltation, load is bounced along the sea bed e.g. Small pieces of shingle or large sand grains
• traction, pebbles and large sediment are rolled along the sea bed

Question 19

Describe how a cuspate foreland is formed

Answer 19

• cuspate foreland is a low lying headland, formed when significant longshore drift is from opposite directions along the coast, sediment is deposited across a bay from both directions forming two spits
• the two spits converge and shelter the area behind in the bay, salt marshes form and enough deposition will form low lying land

Question 20

Describe the essential features of the coastal plain

Answer 20

• flat low lying land adjacent to the sea
• cliff/wave cut notch
• gets flooded during storms

Question 21

What are subaerial processes?

Answer 21

• land based processes which later the shape of the coastline
• weathering (e.g. Freeze thaw, chemical weathering)
• mass movement (e.g. Landslides, slumping)

Question 22

Describe the essential features of the backshore

Answer 22

• the part of the beach closest to the coastline
• dry under normal conditions
• berms (horizontal plateau formed from deposition) without vegetation
• only exposed to waves during storms

Question 23

What is a talus scree slope?

Answer 23

Produced by Mass Movement. The angular blockfall debris accumulates at the cliff foot to form a talus scree slope, a fan shaped mound of material. Undercutting of cliffs by the creation of wave-cut notches can lead to large falls and talus scree slopes at their base