2a- How Coastal Landscapes Develop

Question 1

Abrasion

Answer 1

• sediment carried by waves rub away coastline

Question 2

Wave pounding

Answer 2

• force of breaking waves on coastline

Question 3

Hydraulic action

Answer 3

• water pushed into cracks + compressing air = high pressure = widens the crack

Question 4

3 definitions of Solution

Answer 4

Erosion= dissolving alkaline rock in acidic seawater
Transport= transport of dissolved sediment in water
Weathering= soluable rock minerals dissolve in rain water

Question 5

Attrition

Answer 5

When sediment bumps into each other becoming smoother + rounder

Question 6

Suspension

Answer 6

• floating small sediment carried by water

Question 7

Saltation

Answer 7

-sediment bouncing along sea bed = too heavy to be suspended

Question 8

Traction

Answer 8

• larger sediment pushes or rolled along sea bed

Question 9

Flocculation

Answer 9

• fresh and salt water mixing allowing small particles to clump together until too heavy to be carried + are deposited

Question 10

Freeze thaw

Answer 10

• water enters cracks and freezes expanding = widens crack

Question 11

Salt crystallisation

Answer 11

• sea water evaporates leaving behind crystals in cracks = as crystals grow they put pressure on rock

Question 12

Pressure release

Answer 12

• rocks above eroded = decrease in weight/pressure above so rock expands
  (like releasing belt and stomach goes out)

Question 13

Carbonation

Answer 13

• CO2 in rain makes it slightly acidic = reacts with some rocks + dissolves them

Question 14

Biological weathering (2 types)

Answer 14

Physical = burrowing animals or tree roots push in rock causing rock to split

Chemical= organic acids produced reacting with rock minerals

Question 15

How do headlands and bays form

Answer 15

1- disconcordant coastline = different speeds of erosion
2- bay forms in area of weaker geology and headland forms in area of strong geology

Question 16

How do headlands and bays continue to change over time

Answer 16

• wave refraction round headlands
• caves arches stacks and stumps can form
• waves lose energy due to wave refraction and deposit sediment in bay= beach
• bay can become wider as headland erodes

Question 17

What is wave refraction

Answer 17

1- shallow water in front of headland (wave cut platform) slows a part of the wave down
2- rest of the wave bends and breaks round the headland = erodes headland from side

Question 18

How do cliffs retreat and form

Answer 18

1- erosion at base of cliff between high + low tides = wave cut notch
2- undercutting/ continued erosion at base causes cliff to collapse
3- collapsed material = wave cut platform
4- cycle starts again and cliff retreats

Question 19

How do caves , arches , stacks and stumps form

Answer 19

1- wave refraction on WCP slows down waves directly infront of headland while waves either side bend round + attack cliff from side
2- crack forms = then cave = then arch and so on

Question 20

How do blowholes form

Answer 20

1- waves erode cave in headland
2- structure + bedding planes of rock allow vertical erosion as well as lateral
3- tunnel forms allowing water to flow through cave and out of the top

Question 21

What is a Geo

Answer 21

1- erosion enlarges a fault to form a cave
2- continued erosion causes roof to collapse = narrow steep-sided inlet called a geo

Question 22

What is mass movement + give 3 examples

Answer 22

Movement of material due to gravity
- rock fall
- landslides
- slumping

Question 23

Rock fall

Answer 23

• rocks detached by weathering fall due to gravity

Question 24

Landslides

Answer 24

• sliding of rock along crack or fault

Question 25

What is slumping

Answer 25

- Saturated material becomes heavy + lubricated = collapses along curved line

Question 26

What is a beach + name 2 features found on a beach

Answer 26

- accumulation of material deposited -berms + cusps

Question 27

What are berms and cusps

Answer 27

- ridges formed at high tide mark as sediment is deposited at top of swash -small depressions formed as backwash is channeled down beach

Question 28

What are spits + how do they form

Answer 28

- long extended beaches attached to land at one end + stretch into sea at other - longshore drift carries material along coast = sediment grows out from coast - change in wind direction builds sediment in another direction = recurved end

Question 29

Onshore bars

Answer 29

- a spit that connects 2 areas of land eg: across a bay - salt marshes form behind

Question 30

What is a tombolo

Answer 30

- wave refraction around island = waves lose energy + deposit sediment - beach forms connecting island to mainland

Question 31

What are salt marshes

Answer 31

- vegetated areas of deposition in low energy conditions - submerged at high tide + exposed at low

Question 32

How much does limestone erode per year

Answer 32

0.1m a year

Question 33

How much does clay erode a year

Answer 33

0.8m a year

Question 34

what angle do waves arrive at coast for LSD

Answer 34

45.c

Question 35

Spit

Answer 35

long narrow beach of sand or shingle, attached to land at one end and stretch out across a bay, estuary or change in coastline. Formed as LSD carries sediment into sheltered areas of open water

Question 36

Onshore bars

Answer 36

Formed when a spit continues to grow across a bay or indentation. Lagoons of brackish water are formed behind them.

Question 37

Longshore drift

Answer 37

Process of sediment transportation across a beach. Dependent on the prevailing wind. Sediment is transported with swash at a 45 degree angle up the beach and 90 degree angle back to the sea with backwash