landforms

Question 1

How do wave cut platforms form?

Answer 1

1. Marine erosion, concentrated around the high tide line-> wave cut notch
2. WCN becomes deeper d2 sub-ariel weathering-> weakens cliff face at the top-> unstable and falls under own weight d2 mass movement
   = platform beneath wcn
   -> over time, processes repeat= wcn (normally exposed at high tide)
   BUT length of wcp is limited-> eventually waves cannot reach cliff-> reduces erosion= negative feedback loop

Question 2

What are beaches? what are the different types and features?

Answer 2

A beach= a depositional landform created when sediment is deposited near the coast as waves lose energy, major store in coastal system

Types=
1. swash aligned- waves approach perpendicular-> limited lsd, shingle beach, large sediment
2. drift aligned- waves approach at significant angle-> lsd= sedi travels= spits
Features= berms, cusps, runnels (named on paper f)

Question 3

explain the formation of a spit:

Answer 3

1. LSD deposits sediment-> beach extends out to sea d2 change in direction of coast
2. material is carried further east as waves lose energy and cannot transport sediment-> extending spit
3. secondary winds and wave refraction-> end of spit curves, over time there may be multiple recurved tips= compound spit

Question 4

Outline the processes that lead to the development of barrier beaches (2018)- 4 marker

Answer 4

A barrier beach is usually formed as an extension to a spit (1)
LSD moves sediment along the coastline until there is a change in direction of coast (2)
As a spit develops this can extend across a whole bay, forming a barrier beach (3)
Colonisation of vegetation can stabilise the barrier beach and trap further sediment, keeping the bb above sea level even at high tide (4)
e.g. padre island

Question 5

Explain the formation of a tombolo:

Answer 5

A tombolo= a sand spit that connects the mainland to an island
1. LSD-> formation of a spit-> extends over time as deposition builds this up, eventually may connect island and mainland
2. sand dunes may form along tombolo over time- colonisation occurs e.g. marram grass- gives tombolo stability

Question 6

How do Bars form?

Answer 6

formation of spit-> some sputs continue to extend reaching other side of the bay= bar-> colonisation occurs, stability- water trapped behind the bar= a lagoon e.g. chesil beach

Question 7

explain the formation of a mudflat:

Answer 7

1. salt water flows into the estuary (carrying fine sediment)-> meets river flow (also carrying sediment)- tides and waves-> water flow ceases, no longer can carry sediment= deposition
2. flocculation- individual clay particles group together= larger heavier particles-> small sediment and silt= build up of mud over time where pioneer plants colonise-> more sediment is trapped= mudflat