Landscape Systems Flashcards
What is the littoral zone
intertidal zone extending from the high water mark to coastal areas that are permanently submerged, the foreshore
What are the elements of structure
Geological, forming, lithologies
Elements of geological structure
Jointing, dip, faulting, folding, coastal morphology
Elements of forming
Concordant, discordant coastlines
Elements of lithology
Strata, deformation, faulting
What is strata
a layer or a series of layers of rock in the ground
How are wave cut notches formed
destructive waves hit against the cliff face, causing an undercut between the high and low water marks, mainly as a result of abrasion, corrosion and hydraulic action, creating a wave-cut notch. This notch then enlarges into a cave, and eventually collapses to be level with the sea
Sources of sediment
Rivers (intermittent, sub aerial inland), waves, cliffs, LSD, angle of wave
depositional landforms
Beaches, spits, bars, tombolo, cuspate
what are feedback loops
Negative = nullified
Positive = amplified
What are factors influencing landscapes
Geology, waves, tides, wind, current, geomorphic processes
Types of ocean currents
Longshore currents
Rip currents
Upwelling
What are rip currents
Seawater build up
what are the 3 types of energy inputted into a coastline
kinetic
potential
thermal
what is an output of energy
strong backwash transports sediment away from the coastlome
what is a flow
a form of linkage between 2 stores
what is a store
a store of energy
why might a sediment cell not be a closed system
lsd transports sediment depending on prevailing wind
around barriers like headlands (storms)
sand blown further inland
humans or extreme weather events
how do winds produce waves
generated by frictional
higher wind speed is higher fetch
top of wave moves faster than bottom
why do waves break as they enter the shore
circular orbit changes to elliptical as frictional drag influences the shape and water moleevules come into contact with sea fooor
slowing wave to cause bunch up
crest advanced a heads of the wave (not influenced)
spring tide
high tude
neap tide
low tide
how do rivers gain sediment
terrestrially by erosion transport deposition and lsd
why does a defecit sediment budget require human intervention
hard engineering to stop excessive eroson
why may a spit be recurved
secondary winds > deposition at different angles > salt marsh behind a spit if estuary
how is the rosetta headland formes
constant deposition of sediment through lsd from distributaries due to NW W waves
temp and sea level of glacial period
wurm glacial period
9C lower and 90m lower
why will rias infill with sea level rise
alluvial deposits due to the depth and low velocity and energy
sea level change effect on shingle beaches
higher energy waves due to sea level rise > lsd > rapid change in characteristics
sandbanks why is it being manages
protect beach from excess erosion die to high value property development nearby
effects of changes of processes and flows
reduced retreat of coastline and minimised movement of sediment
how long is the nile delta
6650km
how much rainfall in the nile delta
600mm
discharge of nile delta
3000m3/s
factors influencing the formation of landforms
waves
tides
wind
currents
géomorphic processes
geology
where are distributaries in the nile delta
cairo
when was the aswan dam built
1964
caused imbalance
how much was the reduction of sediment due to aswan dam
120 million to trace amounts
where is flamorough head located
between salt burn and flamborough head
rock upland
60km long
geology of FH
adjacent to north york mooks
rise 400m
sandstone shale and limestone
glacial deposits
fetch FH
1500km
shale and clay erosion rate FH
0.8 metres a year
sandstone and limestone erosion rates
0.1 metres per annum
prevailing wind FH
N/NW
FH sediment sources
between salt burn and flamboyrogh sub cell
cliff erosion
boulder clay deposits
river sediment (river Esk)
beach sediment increas FH
9245m3 (2008-2011)
cliffs in FH
vertical face lowered by mass movement 40*
glacial till overlain
shore platforms what is the bay called Fh
high energy erosion
robin hood bay has lower lias shales
headlands FH
wave refraction concentrated headland
joints exploités
slewing bay
blowholes and 50 geos
what are the beaches like Fh
few well developed
sand and shingle accumulate
waves remove sediment before deposition
lsd medium
why do sea levels change daily
high and low every few hours
air pressure
winds push water to coast
why do sea levels change long term
relative to land
eustatic and isostatic
when was the last glacial maximum
20,000 years afo
what is eustatic thermal change
water expands
ocean absorbs heat
thermal expansion
fossil fuels
anthropogenic forcing
what is isostatic change
uplift experiences by land following the removal of ice sheets as post glacial rebound
mantle pushed down by ice sheet
subsidence
sinking of land due to the weight of ice sheet
weight of sediment into thames
which parts of UK are rising
N W
which parts of UK are sinking
S E
isostatic change accretion
sediment added to landform
balanced by subsidence
example of accretion
1.1mm sinking
2.2mm eustatic rising
3.9mm rise
past activity of tectonics
uplift of mountains
local tilting
alpine folding
eurasian african
output of energy
long wavelength (heat emission)
terrestrial radiatoon
what is an output of matterial
aeolian processes
erodes material transported
dynamic equilibrium
when a system is disturbed and the system undergoes self regulation to change and restore it
store in a sediment cell
point of accumulation of energy or material
flow between sediment cell
the linkage (lsd)
when will a wave topple over
the depth is less than 1.3x the wave height
what happens to wave heighhtr as it enters the shore
increases
what is backwash
the force of gravity acting perpendicular to the coastline
what is wave refraction
concentrated energy on headland
comes into contact with shallow water causing friction
wave wave refracts around the headland and drag against sides
low energy landforms
beaches and spits
deposition exceeds erosion
estuaries
high energy landforms
headlands
cliffs
wave cut platforms
strong prevailing wind
sediment comes from
streams and rivers
cliff erosion
offshore sandbanks
shells and coral
sediment cells are
closed systems
explain the concept of a sediment cell
closed system
2 distinct features of land
dynamic equilibrium
erosion transportation and depositions
movement of matter ❌
types of erosion
hydraulic action
abrasion
corrasion
attrition
solution
What affects rate if erosion
Wave height
Fetch
Sea depth
Wave refraction
Protection of a beach
Human activity
How does lithology affect geomorphic processes
Rock characteristics
Erosion resistance
Permeability
Jointed rocks
How does structure affect geomorphic processes
Strata (relations)
Deformation and tectonic activity
Faulting and fractures
Con/discordant coastlines
Dip
Types of transportation
Traction
Saltation
Suspension
Solution
LSD
Equation for energy relation wave high
E=LH2
Smallest increase in height results in a bigger change in energy
ablation
loss of ice or snow from a glacier
aeolian
eeosional, transportation and deposition
chemical weathering
in situ breakdown of rocks by chemical processes like oxidation and hydrolysis
concordant
coastline with andd of géologies lying paralell to shire
deflation
erosion of clay and silt by wind action
fetch
distance of ppen water in one direction from a coastline over which the wind can blow
What are the factors affecting temperature
Earths orbit
Energy from sun
Composition of atmosphere
Tilt of earth
What was the sea level and temp of Tyrrhenian relative to today
3C higher and 20m higher
What happens when global temps fall
Sea level fall 2m
Precipitation id snow and turns to ice
Molecules contract
Emergent landforms
Raised beaches
Abandoned cliffs
Marine terraces
What is a raised beach
Higher shore platform more inland
What is an abandoned cliff
A relic cliff behind a raised beach
Normal landforms
What is a marine terrace
Larger raised beach
Who manages sandbanks
Poole harbour commissions
Poole borough council
Sediment cell
What is the need for sandbanks
High value prop
£10m houses
Residential demand
Beach’s for tourists
Protection
Ferries
Strategies used to manage sandbanks
Rock grognes
Beach recharge
How to rock groynes manage sandbanks
Restrict sediment
Ships into harbour
Absorb waves
W/o 1.6m/y
How does beach recharge manage sandbanks
Dredged offshore (£20/m3)
‘Rainbowing’
How has pakiri developed
High quality sand 9mangawhai-pakiri)
50km from Auckland (35% GDP)
When did Mangawhai stop sand mining
2005
How much sand was mined between 1994-2004 in pakiri
165,000m3/y
Why is sand mining non renewable
Few rivers
5x output than input
Closed sediment budget
How does sand mining impact landforms
Beaches wide and flat
High energy waves
Vegetation loss (wind)
What do studies of pakiri show
Erosion rate increase
Climate change and extraction will equal 35m erosion in 100yrs
