landforms due to deposition

beaches, sand dunes, spits, bars

define a beach

gently sloping area of land formed by the accumulation of sand or pebbles due to deposition

where do sandy and pebble beaches occur? why?

• sandy: in sheltered bays where waves have less energy- mostly constructive

• pebble: areas of high energy waves where cliffs are being eroded

explain the cross profile of a beach and the characteristics for a pebble and sand beach

• the side profile of a beach, usually contain berms

• sandy: gently sloping profile

• shingle: steeper profile

  profiles have larger material at the top due to high energy storms being able to carry them. smaller material found nearer to the ocean as waves break here + erode via attrition

what are sand dunes? what is the criteria needed for them to form?

• large heaps of sand which form on the dry backshore of dry, sandy beaches mostly formed by saltation

• an object to form against, large amnt sand, onshore wind to move sand to the back of the beach, large flat beach

how are sand dunes formed?

sand moves up the windward slope → height builds until dune structure becomes unstable → sand falls down the leeward slope

how and why do sand dunes change with distance?

size increases inland because long-rooted marram grass and other vegetation binds sand together preventing further migration while helping to build dune height.

embryo dune → foredune → fixed dune

define a spit and 2 key reasons for spit formation.

• spit: long, narrow finger of sand/shingle extending into the sea from the coastline

• change in coastline direction, area affected by longshore drift