landforms of deposition Flashcards
beach
accumulation of sediment where land and sea meet
sand - gentle slope
as small so compact when wet
little percolation
most of swash returns as backwash forming ridges and runnels parallel to shore at low water mark
shingle - steep
water percolates rock so limited backwash
storm beach
strong swash at spring high tide throws boulders to back of beach forming ridge above normal high tide mark
beach cusp
semi circular shaped depressions
swash and backwash strong
junction sand and shingle
sides channel water to middle
produce strong backwash deepening cusp
berms
below storm beach series of ridges marking other high rides
built by constructive waves
ripples
below beach cusp ripples form on sand due to wave currents
swash aligned beach
parallel to income waves
low LSD
irregular coasts where LSD stopped
drift aligned beach
parallel direction dominant LSD
sediment transported
can extend out from coastline
spit formation simple + recurved
elongated ridge that projects into sea or estuary
1) prevailing wind (SW) causes swash to move up beach at angle carrying material
2) backwash moves down beach at 90 due to gravity
3) continues and sediment moved from west to east
4) reach change in shape coastline and material is deposited
5) fine material is carried further, extending the spit
6) second most dominant wind direction causes end of spit to curve
simple = straight or recurved
compound = recurved ridges
tombolo formation
spit that joins island to mainland
eg chesil beach linking isle of portland to mainland, 30km long
bar formation
spit develops across bay due to no strong flow water from landward side
forms lagoon
barrier beach formation
elongated bank deposited material parallel coast not submerged
sand dunes can develop establishing beach further
offshore bar
ridge material semi submerged
material builds seaward of breaker zone
