depositional landforms Flashcards
what is a spit
a long narrow ridge of sediment that is attached to the land at one end
what must be greater than output for a spit to form
the input f sediment
what type of beach is needed for a spit to form
a drift aligned beach which is controlled bs LSD
where does the sediment for a spit to form come from
coastal or/and river erosion
what trasnportation processes take place in the process of a spit formation
LSD and saltation
what is LSD
the movement of sediment along a beach through a zig zag movement
how does the prevailing wind play a role in spit formation
it controls the direction of waves which pushes sediment upshore at a 45 degree angle
what waves are needed in the formation of a spit
constructive waves
what is the full process of a spit formation
-abundance of sediment on a drift aligned beach from cliff or river erosion
-prevailing wind pushes constructive waves up beach at a 45 degree angle
-swash pushes sediment upshore and it taken back down by gravity
-lsd pushes sediment along a beach
-as coastline changes direction, lsd continues in original direction
.sediment is deposited across a bay
-deposited material forms a peninsula known as a spit
-overtime a spit will curve due to wave refraction
why are erosional and weathering processes important in forming spits
it provides a beach with an abundance of sediment
what is a barrier beach
a ridge of sediment that runs parallel to the shore and rises slightly above sea level.
why can some spits not form barrier beches
because some estuarys have a strong current from the river so sediment cannot be deposited
what is required for a barrier beach to form
-an abundance of sediment
-drift aligned beach
how is a barrier beach formed
same process as a spit
-but sediment is deposited across a whole bay due to no strong river current and no change in wind direction
what forms behind a barrier beach
a lagoon
what is a tombolo
its a sandy or shingle spit that joins an island to the mainland
how does a tombolo form
its the same process as a spit
what is an offshore barrier island
a barrier beach which has become seperated from the mainland by rising sea level
what does fluvial mean
river
how does an offshore barrier beach form
a bar gets broken down into sections due to high rates of erosion and rising sea levels
where does a saltmarsh form
behind a spit
what conditions are needed for a saltmarsh to form
low energy sheltered area
what is a halophytic plant
a salt resistant which can withstand being submerged by the tide
what is a pioneer plant
the first plants to start developing before being replaced by others
what is a saltpan
hollows in the saltmarsh where sea water is trapped and evaporated, it creates very salty areas where even halophytic plants cant grow
what is flocculation
when fluvial + sea water mix, it causes an electric charge and causes clay to merge with each other, it grows in mass and gets deposited.
what are some of the pioneer plants that first develop on saltmarshes
eelgrass and green algae
