LANDSCAPE CHANGES - TIME SCALES
1.1.8
RAPID CHANGES - CLIFFS
SEASONAL CHANGES - BEACHES
MILLENNIA
EMERGENT LANDFORMS
SUBMERGENT LANDFORMS
high energy/storm events
rapid mass movement
sudden change to cliffs
example: FAIRLIGHT, ENGLAND
slumping - clay cliffs - heavy rainfall and wet winters make it weak
mud flows
undercutting of base by high energy waves
WINTER
major storms
high energy waves
destructive waves
strong backwash
profile = convex, flattened lower section - steep upper
offshore bar
SUMMER
no major storms
low energy waves
constructive waves
builds up beach
gradient increases - low wave steepness
return the lost sediment from winter
LONG TERM, STEADY, EQUILIBRIUM
EUSTATIC
affects WHOLE WORLD
sea level changes
alteration in volume of water
during and after ice age - temperature decreased, water froze, suspended hydrological cycle, decreased sea levels
after ice age - increased temperature, ice melts, increased sea level
tectonic change
ISOSTATIC
increase or decrease in height of land
ice age - ice = heavy, increased weight of land, land sinks, higher sea level (compression)
ISOSTATIC REBOUND - ice melts, decreased weight of land, land rises, lower sea level
tectonic uplift
LOCAL
end of ice age - isostatic rebound - faster than eustatic rise
raised beaches, arches, caves, stacks - degraded form
example: RHOSSILI BEACH, SWANSEA
sub-aerial processes become more infuencial
eustatic rise = faster than isostatic rebound
water floods land - fills up landforms
RIA
floodplains and valleys are flooded - estuary
FJORD
flooding of glaciated U-shaped valley
important routes for water traffic - ferries
very deep and wide