Coasts

Question 1

What is a littoral zone?

Answer 1

A littoral zone is the wider coastal zone including adjacent land areas and shallow parts of the sea just offshore.

Question 2

What is back shore?

Answer 2

Above high tide level and only affected by waves during exceptionally high tides and major storms.

Question 3

What is nearshore?

Answer 3

Shallow water areas close to land and used extensively for fishing, coastal trade and leisure.

Question 4

What is offshore?

Answer 4

The open sea.

Question 5

What is the sediment supply?

Answer 5

The process of weathering and erosion produce sediment which is transported and deposited to produce coastal landforms.

Question 6

What can sediment supply come from?

Answer 6

• Tidal currents
• Rivers discharge
• Coastal erosion

Question 7

What is geology?

Answer 7

Geology is the physical structure and arrangement of a rock.

Question 8

CLASSIFICATION OF COASTS.

Rocky vs coastal plains. Describe rocky coasts.

Answer 8

• Rocky coasts can have high or low relief
• Results from resistant geology (hard rocks)
• Often in a high energy environment (destructive waves). e.g. Galicia

Question 9

CLASSIFICATION OF COASTS.
Rocky vs coastal plains.
Describe coastal plains.

Answer 9

• Referred to as ALLUVIAL coasts
• Sandy + estuarine coasts (found at the mouth of the river)
• Found near areas of low relief. e.g Sancti Petri

Question 10

CLASSIFICATION OF COASTS.
Formation processes (primary coasts vs secondary coasts).
Describe primary coasts.

Answer 10

-Dominated by land-based processes —> as deposition at the coast from rivers/new coastal land formed from lava flow. e.g canary island (Volcanic activity)

Question 11

CLASSIFICATION OF COASTS.
Formation processes (primary coasts vs secondary coasts).
describe secondary coasts.

Answer 11

-Are dominated by marine erosion or depositional processes. e.g canary island (volcanic activity)

Question 12

CLASSIFICATION OF COASTS.
Geology.
What are the three types of rocks?

Answer 12

Igneous:

• Magma cools down in volcano (intrusive)
• In the Earth’s surface (extrusive)
  e. g. Granite, Basalt (Canary island)

Sedimentary:

• Layers of sediment
  e. g. limestone, sandstone (Mediterranean)

Metamorphic:

• Heat + pressure exerted onto sedimentary rock + change characteristics.
  e. g. Marble, slate (West coasts of Ireland)

Question 13

CLASSIFICATION OF COASTS.

Sea level change.

Answer 13

Emergent coasts:

• Where coasts are rising relative to sea level, due to tectonic uplift or glacier activity
  e. g. Iceland, Hawaii

Submergent coasts:

• Are being flooded by the sea, either due to rising sea level and/or subsiding land.
  e. g. Maldives, Bangladesh

Question 14

CLASSIFICATION OF COASTS.
Tidal range.
3 types of tidal ranges.

Answer 14

• Micro-tidal coasts: tidal range of 0-2m
  e. g. Mediterranean coasts
• Meso-tadial: Tidal range of 2-4m
  e. g. Indian Ocean, South East Asia
• Macro-tidal: range greater than 4m.
  e. g. Atlantic Ocean

Question 15

CLASSIFICATION OF COASTS.
Wave energy.
2 types.

Answer 15

Low energy:

• Sheltered coasts with limited fetch and low wind speeds which result in small waves.
  e. g. Mediterranean coasts

High energy:

• Exposed coasts, facing prevailing winds with long wave fetches which result in powerful waves.
  e. g. Comillas, Galicia

Question 16

When do destructive plate boundaries occur?

Answer 16

Destructive plate boundaries occur when oceanic & continental plates move together and create fold mountains (forced up).

Question 17

When do constructive plate boundaries occur?

Answer 17

Constructive plate boundaries occur when plates move apart.

Question 18

What is a hot spot?

Answer 18

A hotspot is a region within the Earth’s mantle from which heat rises - facilitates melting of rock.

Question 19

How are igneous rocks formed?

Answer 19

-Igneous rocks are formed as a molten mixture of minerals (magma - upper part of the mantle). In places called hot spots, the crust is very thin/heavily cracked e.g. constructive plate boundaries. At destructive plate boundaries - produced different minerals.

Question 20

Rate of erosion of igneous rocks:

Answer 20

VERY SLOW

-Strong and hard-resistant rocks e.g Granite, Basalt.

Question 21

How are metamorphic rocks formed?

Answer 21

Metamorphic rocks are formed when exposed to high levels of heat (e.g. when magma intrudes into a rock/lava runs over the top) - changes minerals into new ones.

Question 22

Rate of erosion of metamorphic rocks:

Answer 22

SLOW

• Crystalline rocks, resistant to erosion. Crystals orientated in one direction (foliation) - produce weaknesses.
  e. g. Slate, Marble

Question 23

How are sedimentary rocks formed:

Answer 23

-Sedimentary rocks are worn away by weathering + erosion. Fragments torn away and transported to another places (these are called sediments). Eventually will be deposited on top + weight will compress sediments, making them stick together to make a rock —> recess called lithification.

Question 24

Rate of erosion of sedimentary rocks:

Answer 24

MODERATE/FAST

• Most sedimentary rocks are clastic and erode fast. Geological structure is weak.
  e. g. sandstone, limestone.

Question 25

What causes waves?

Answer 25

Most waves form when wind blows over water. Its’ size is related to the wind speed as wind creates a frictional drag which produced movement in the upper surface of the water.

Question 26

What is wavelength?

Answer 26

Wavelength is the distance between the crest of two waves.

Question 27

What is fetch?

Answer 27

Fetch is the distance of open water over which the waves move. The greater the fetch, the larger the wave.

Question 28

What are swell waves?

Answer 28

Swell waves are waves originating from mid-ocean which appears as larger waves amongst smaller locally - greater waves. Not all waves originate locally, some originate in mid-ocean, and maintain their energy for thousands of miles. e.g. on the UK coast.

Question 29

What are the two types of waves?

Describe the C———– waves.

Answer 29

Constructive & Destructive.
Wave form: low, surging waves - with long wavelength
Wave break: strong swash, weak backwash
Beach gain/loss: beach gain (constructive)

Constructive waves —> less frequent (6-9 per minute), so wave energy dissipates + deposits over a wide area (weakening the backwash)

The swash of a constructive wave deposits larger material at the top of the beach-creating a berm (usually a shingle)
As the berm build up, the backwash becomes weaker (draining by percolation, rather than down the beach). It only has enough energy to move smaller material, so beach material becomes smaller towards the shoreline

Question 30

What are the two types of waves?

Describe the D———– waves.

Answer 30

Wave form: high, lunging waves- with s short wavelength.
Wave break: weak swash, strong backwash
Beach gain/loss: beach loss (destructive)

Winter: destructive waves occur at a higher frequency (11-16 per minute)
Berms are eroded by plunging waves and high-energy swash
Strong backwash transports sediment offshore (depositing it as offshore bars)
Sometimes, the backslash exerts a current known as a rip or undertow- dragging sediment bask as the next wave arrives over the top