Case Study Overstrand Landforms

Question 1

Location?

Answer 1

North-east coastline in East Anglia, e.g. Overstrand

Question 2

Waves?

Answer 2

Powerful and more destructive as they are built up over a large fetch: strong swash and weak backwash

Question 3

Fetch?

Answer 3

3000km

Question 4

Prevailing wind direction?

Answer 4

From the NE: waves hit cliff almost straight on- swash align beach and so erode rapidly

Question 5

What is cliff made of?

Answer 5

Very weak: chalk bedrock is covered by a thick (2-5m) layer of glacial till which is unconsolidated so eroded easily

Question 6

How do waves erode cliff and what do they create

Answer 6

Waves erode cliff by process of hydraulic action/pressure, abrasion and solution, creating a wave cut notch at the base of the cliff

Question 7

What happens to cliff after being eroded?

Answer 7

Cliff collapse as unsupported cliff material slumps under its own weight - most common during heavy rains when cliff materials because saturated and very heavy.

Question 8

What about other types of cliffs are there, what causes them?

Answer 8

Some are not very high or vertical because the unconsolidated glacial till collapses easily so they are instead gentle sloping and ave. 30m high - the underlying chalk is exposed in places

Question 9

Erosional landform: Cliff retreat?

Answer 9

The cliffs retreat rapidly ave. 1m per year - a single powerful storm can erode hundreds of tonnes of material.

Question 10

Erosional Landform: Wave cut notch visibility?

Answer 10

Wave-cut notch is only visible in some places because the unconsolidated glacial till collapses frequently, obscuring the notch.

Question 11

Erosional Landform: wave cut platform (beach) description?

Answer 11

There is a gentle sloping wave cut platform in front of cliffs: left by rapid retreat of cliffs which is covered at high tide but exposed at low tide.

Question 12

Erosion Landforms: wave cut platform (beach) coverage?

Answer 12

It is covered with a sandy beach: composed of slumped cliff material in process of being removed by longshore drift from the SE to the NW

Question 13

Depositional landforms: Spit (Blakeney Point) waves?

Answer 13

Waves approach coastline at an angle: approach north-facing coastline from NE, which is the prevailing wind direction (drift align beach)

Question 14

Depositional Landforms: spit (Blakeney point) longshore drift?

Answer 14

Long shore drift moves material EAST to WEST: waves move up beach at angle but returns at right angles due to gravity - material is moved along beach from east to west in process

Question 15

Depositional Landform: spit (Blakeney Point) coastline?

Answer 15

Coastline changes direction as the coast bends SW as material being transported by longshore drift is deposited in the sheltered water where the coast changes direction.

Question 16

Depositional Landforms: spit (Blakeney Point) finger of land, length & shingle?

Answer 16

Longshore drift from east to west provides more and more material deposited leading to finger of land being developed - Blakeney point is apx. 15KM long and shingle bank up to 10CM high

Question 17

Depositional Landforms: spit (Blakeney point) curved ends?

Answer 17

Occasional storm winds from north and north west, forces the end of the spit to curve around - Blakeney point has at least 3 prominent curved ends

Question 18

Depositional Landforms: salt marsh (Blakeney Marsh) wave energy?

Answer 18

Sheltered water behind the spit so wave energy is LOW

Question 19

Depositional Landforms: salt marsh (Blakeney marsh) sediment?

Answer 19

This occurs in rivers such as the Stiffkey Freshes Creek as they empty into this area on the way to the sea - silt and other fine sediment that they are transporting is deposited in sheltered water

Question 20

Depositional Landforms: salt marsh (Blakeney marsh) developing of salt marsh?

Answer 20

Over time silt builds up and plants able to colonise it e.g. spartina. The plants trap further sediment around their roots and stems and permanent marsh becomes established with +++ range of plants e.g. sea lavender, sea campion, samphire

Question 21

Importance of Blakeney Marsh?

Answer 21

It has become an important international breeding are for sea bird colonies e.g. arctic terms, oyster catchers