3.2 Coastal Landforms Flashcards

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1
Q

What factors do affect waves?

A

They are energy that flow through water factors such as:

  • Wind strength (stronger fetch)
  • Wind duration (longer fetch)
  • Water depth
  • Fetch
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2
Q

What is a fetch?

A

Uninterrupted distance across water that wind blows.

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3
Q

What is a swash?

A

Flow of water up beach as wave breaks.

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4
Q

What is a backswash?

A

Flow of water down beach.

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5
Q

What are constructive waves?

A
  • Depositional waves
  • Low frequency
  • Strong swash, weak backswash
  • Low energy, low frequency
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6
Q

What are destructive waves?

A
  • Erosional waves
  • Larger fetch
  • Weak swash, stronger backswash
  • High energy, high frequency
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7
Q

What are subaeral processes?

A

Land-processes which can alter the coastline such weathering.

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8
Q

What is weathering?

A

The breakdown of rocks, with no movement.

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9
Q

What is mechanical weathering? (freeze-thaw)

A

Exertion of physical force of breaking material.

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10
Q

What is chemical weathering?

A

Chemical reaction with products that break down material. (acid rain)

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11
Q

What is biological weathering?

A

Plant/bacteria/animal action eg plant roots or overgrazing.

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12
Q

What is mass movement?

A

The sudden movement of large amounts of material typically rock and soil.

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13
Q

What is longshore drift?

A

Waves hit coast at prevailing wind angle, swash carries material up beach angle, backswash carries material down beach at 90 degrees.

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14
Q

What is a spit?

A

Longshore drift desposits sediment across a bay.

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15
Q

What is a Bar/Barrier beach?

A

Spit extends across bay, forms lagoon behind it.

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16
Q

What is a tombolo?

A

Bar connecting coast to offshore island.

17
Q

What is a bayhead beach?

A

Sediment deposited into bay forming a beach.

18
Q

What is a salt marsh?

A

Flat muddy coastal wetland on low energy coast.

19
Q

What is an Offshore bar?

A

Destructive waves erode sediment which washes back into sea, forming bar parallel to coast.

20
Q

What is a cupsate foreland?

A

Longshore drift occurs in opposite directions forming a triangular shape.

21
Q

What is a sandy beach?

A

Flat stretch far inland, constructive waves, sand dunes.

22
Q

What is a pebble beach?

A

Steep, short, far inland, destructive waves, large pebbles at back.

23
Q

What is gravity settling?

A

When water energy is too low to transport sediment anymore.

24
Q

What is flocculation?

A

Where small charged particles (eg clay) clump together + sink in the water.

25
Q

What are the 4 types of sediment transportation?

A
  • Traction: large boulders and pebbles are rolled alog the river bed.
  • Saltation: small stones, pebble and slit bounces along the river bed.
  • Suspension: Fine material such as clay and sediment us carried by the water.
  • Solution: Dissolved minerals carried by the river.
26
Q

What are the 4 erosional processes?

A
  • Abrasion: rocks collide with cliff and wear it away.
  • Attrition: peices of bedload collide with each other and get smaller
  • Corrosion: *acids/chemicals dissolve certain rocks eg chalk, limestone
  • Hydraulic Action: water is compressed into cracks in cliff which wears away.
27
Q

What is a wave-cut notch?

A

Hydraulic action + abrasion erods the base of the cliff, creating a dent.

28
Q

What is headlands and bays?

A
  • Less resistant strat erode away - bays
  • More resistant strata jut out - headlands
29
Q

How does a wave-cut platform form?

A

Erosion of the wave cut notch will make the cliff collaose cliff retreats over time backswash carries the collapsed rocks away, forming a platform.

30
Q

How does a coastal stump formed?

A
  • Abrasion & Hydraulic action widen faults in headland which creates a cave.
  • Over time, 2 back to back caves may break theough a headland creating an arch.
  • The roof of the arch eventually collapses as it is unstable creating a stack.
  • Stack erodes away turning into a stump.