Key Facts Flashcards by Eloise edwards

What is an input

5 examples

How sediment is brought into the system
Wind 
Waves 
Tides 
Currents
Sediment

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Output

When sediment is washed out to sea or deposited further along the coast

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What are flows or transfers

4 examples

Processes that move sediment within the system 
Weathering 
Erosion
Transportation
Deposition

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What are stores/ components

3 examples

Landforms that store sediment
Beaches
Dunes
Spits

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Negative feedback and example

Change In The system that chases other charges which have the opposite effect

As a beach is eroded, cliffs are exposed to wave attack, sediment eroded from cliffs I’d deposited, causing it to grow in size

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Positive feedback

Example

Change in the system that chases other changes with same or similar effect

Beach starts to form and grow - slows down waves - more sediment deposited - increasing beach size

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Dynamic equilibrium

Inputs and outputs are balanced

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How is wind created

By air moving from areas of high to low pressure area

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What happens to the wind during a storm and how does this effect the waves?

Pressure gradient is high so strong winds therefore powerful waves

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What is the prevailing wind

Wind constitently blows from the same direction causing high energy waves

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How are waves created

Created by wind blowing over sea, friction between wind and sea gives water a circular motion

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What are the 2 types of waves

Constructive

Destructive

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7 characters of constructive wave

Low frequency
6-8 per minute
Low and long
Strong swash
Weak back wash
More elliptical profile 
Flat and wide beach

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7 characteristics of a destructive wave

10-14 a min
High freq 
More circular
High and steep
Weak swash
Strong backwash
Steep beach

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What are tides, how are they caused and what do they affect

They are the periodic rise and fall of the ocean surface
Caused by gravitational pull of the moon and sun
Affect the position at which waves break on the beach

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What are currents, what causes them

General flow of water in one direction along the coast

Caused by wind, variations in water temp or salinity

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6 characteristics of high energy coast

Large powerful waves
Strong winds 
Long fetch
Steep shelving offshore zone
Usually dance covers and rocky landforms
Rate of erosion higher than rate of deposition

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6 characteristics of low energy coasts

Small gentle waves
Gentle winds
Short fetches
Gently sloping offshore zone
Usually have salt marshes and tidal mudflats
Rate of deposition is higher that erosion rate

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5 sediment sources

Rivers 
Sea level rise
Cliffs
Crushed shells
Offshore deposits

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What is the sediment budget

Difference between the amount of sediment the enters the system and the amount that leaves

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2 types of sediment budget

Positive- more sediment enters than leaves. Coastline builders outwards

Negative- more sediment leaves. Coastline retreats

What are sediment cells

Also called littoral cells
Lengths of coastlines which are self - contained so the processes of one cell don’t effect movement of cells in another cell
Closed coastal system

6 types of erosion

Abrasion/corrasion
Hydraulic action
Cavitation
Wave quarrying
Corrosion/solution
Attrition

4 types of material transportation and what they are

Solution - substances that can dissolve are carried in water

Suspension - very fine material such as silt is whipped up by turbulence and carried in water

Saltation - larger particles such as pebbles are forced to bounce along the sea bed by water

Traction - late particles such as boulders are pushed/rolled along sea bed by force of water

Deposition | 2 types

When material being transported in dropped on the coast 2 types Marine Aeolian

Marine deposition

When sediment is carried by seawater and dropped

Aeolian deposition 2 types

When sediment carries by wind is deposited Surface creep - process similar to traction where wind rolls sand grains along surface Station - wind is strong enough to temporality lift drain tho airflow for up to 30 m

Sub aerial weathering and types

Gradual break down of rocks by agents such as ice and plants, weakens the cliffs making them more vulnerable to erosion Salt Freeze thaw Chemical Wetting- drying

Mass movement and 5 types

``` Shifting of material downhill due to gravity Slides Slumps Rockfalls Mudflows Soil creep ```

What are slides

Material shifts in straight lines

What are slumps

Material shifts with a rotation

What are rockfalls

Material breaks up and falls down as parts

Mudflows

Material flows downslope

What is salt weathering how is caused

Caused by saline water Water enters pores or cracks at high tide Tide goes out, water evaporates forming salt crystals They form and expand Exert pressure on rock Pieces fall off

Where does freeze thaw occur and how does it happen

``` In areas where temp fluctuates above and below freezing Water enters joints and crevices Water freezers and expand Repeats and weakens rock Pieces fall off ```

Chemical

Breakdown of rock by changing its chemical composition CO2 in atmosphere dissolves in rainwater Forms weak carbonic acid Facts with rocks containing calcium carbonate Gradually dissolves rocks

Wetting and drying

Rocks such as clay gets wet and expands and this pressure weakens Gradually pieces fall off

How does slumping occur | 3

Rainwater soaks Clay Heavier = slump Lubricates weaknesses causing slip plane Hubby tide causes notch and undertcuting, Clay has no support so slumps

Oscillatory waves

Waves that move ina circular motion when water is it in is deeper than the wavelength

Translators waves

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Coastal zone parts 9

Back shore 1 Foreshore 2 Inshore 3 Offshore 4 Near shore - is foreshore and inshore and contains 3 zones Swash zone - 1 Surf zone - 2 Breaker zone 3 High and low water mark

Spring tide

Highest monthly tidal range as the moon orbits the Earth twice in a lunar month the moon sun and earth in a straight line tidal raising force strongest

Neap tide

Lowest monthly tidal range Also twice a month sun moon oppositions at 90° perpendicular to each other in relation to eachotger backwards L shape, sun at top earth in middle and moon to the left

Tidal surges

Occasions when meteorological conditions give rise to strong winds which produce much higher water levels then there is a high tide

What are 3 type of currents

Longshore or littoral drift - when waves approach coastline at angle so current is parallel to shoreline RIP - strong currents moving away from shoreline Upwelling - movement of cold water from deep in the ocean towards surface

6 factors affecting coastal erosion

Wave steepness and breaking point Fetch Sea depth Coastal configuration Beach presence Human activity

Concordant coastline

Rocks running parallel to coastline

Disconcordanr

Rocks run at right angles to coast

4 types of chemical

Oxidation Hydration Hydrolysis Carbonation

What is soil creep as mass movement

Where slow but continuous moment of soil particles downslope