Physical systems

Erosion

the wearing away of rock which gets transported

Hydrualic action

the wearing away of rock through water pressure

Abrasion

the breaking down of rocks through being hit against a cliff

Attrition

when a rock becomes smoother and smaller after being hit against a cliff

Solution

when rocks dissolve due to chemicals in the water

Pounding

high energy waves hitting a cliff

Weathering

the wearing down of rocks

Freeze-thaw weathering

The process of water getting into a crack and continually freezing and thawing until the rock splits

Pressure release

after erosion occurs the rock underneath expands causing the top layer to crack

Thermal expansion

heat expands the rock causing the surface layer to flake off

Salt Crystalisation

salt solution gets into a rock, crystalises, and expands causing the rock to split

Chemical Weathering

the process that breaks down rock through chemical changes

Biological Weathering

the breakdown of rocks by living things

Types of Mass Movement

rock fall, slumping, slides

Traction

large rocks rolled along the sea bed

Saltation

small stones are bounced along the river bed

Suspension

small stones carried by the current

Headland

a narrow piece of land that projects from a coastline into the sea

Crack

a crack in a headland

Cave

an eroded away crack

Arch

a cave that has been eroded to the other side of a headland

Stack

an arch that has fallen leaving a tall rock stack

Stump

an eroded stack

Contructive Waves

low frequency, short waves that have a bigger swash

Destrcutive Waves

high frequency, high waves that have a bigger backwash

Tidal range

the difference in water level between a high tide and a low tide

Small scale currents

transport sediment around a coastline

Global scale currents

transfer heat across the world

Lithology

physical and chemical compostion of a rock

Permeable and porous

allows water to go through it

Concordant coastline

same geology, parallel to the coastline

Discordant coastline

different geology, perpendicular to the coastline

positive feedback loop

accelerates a change

negative feedback loop

negates a change

Fetch

the distance in which the wind blows over water

Oblique wind

wind hitting the coast at an angle

Onshore wind

wind hitting the coast directly

Sediment cell

an area with a self contained coastline

Wave Frequency

the number of waves passing a point each second

Crest

highest point of a wave

Trough

lowest point of a wave

Wave height

the difference between the crest of a wave to the trough

Wave length

the length from one crest to another

Examples of depositional landforms

spit, tombolo, delta, beach

Longshore drift

the movement of sediment along a beach

High energy coastline

Yorkshire Coast

Low energy coastline

Rhone Delta

Flocculation

clay mixes with salt and sticks together

Eustatic change

global change in sea level

Isostatic change

local change in sea level

Emergent landforms

formed during high sea levels and exposed when sea levels fall

Examples of emergent landforms

raised beaches, marine terraces, abandoned cliffs

Submergent landforms

landforms created as a result of rising sea levels

Examples of submergent landforms

rias, fjords, shingle beaches

Rias

flooded river estuaries

Fjords

submerged glacial valleys

Shingle beaches

transported heavier sediment

Wave Refraction

when a wave gets bent around a headland reducing the energy directed at the coast

Mangement strategies at Sandbanks

beach recharge, groynes

Reasons why Sandbanks needs managing

High residental values, tourist attraction, entrance to Poole Harbour

How long does it take for sand to replenish?

9000 years

Impacts of sand extraction on Mangawhai-Pakiri

altered beach currents, more mass movement, beaches are flatter

Amount of sand extracted from MW-P from 1994-2004

165,000m3

Definiton of dynamic equilibrium

when a system is constantly changing to reach a state of balance

Types of inputs in a system

Thermal energy, kinetic energy, wind energy

Reasons why the yorkshire coast is high energy

1500km long fetch, weak geology

Reasons why the Rhone delta is low energy

short fetch, low wind speeds

Rhone delta management stratergies

humans have merged 3 streams into 1

Changes in the Rhone delta

rising sea levels leads to more erosion, more storms due to warmer weather

Amount of money spent on sea defences

15 million euros

Types of management in the Rhone delta

gabions, rockwalls

Main reasons of eustatic and isostatic changes

variation in earths orbit, solar output, volcanic eruptions

A negative of groynes

starves other areas of sediment

A postive of groynes

effective, cheap

A positive of beach replenishment

cheaper

Origins of sediment

terrestrial, offshore, human

Erosion rates of the Yorkshire Coast

0.8m to 0.1m per year