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