coastal landforms Flashcards
how are beaches formed?
-on a low lying coast if loose material like sand is available.
-carried onshore by the swash effect of waves.
the waves slow down their energy drop and material is deposited.
-backwash effect of the waves can extend the beach by longshore drift
how is a sand dune formed?
-sand is picked up by the wind and bounced across the beach surface by saltation
-the sediment that was carried up the beach by saltation starts to get deposited around the high water mark.
-the wind comes into contact with and obstacle like a rock or a shell, wind slows down and deposits its sand and it starts yo build against the obstacles.
how are bays and headlands created ?
headlands are formed when the sea attacks a section of coast with alternating bands of hard and soft rock. the bands of soft rock erode faster than the bands of hard rock. this leaves a bulge of land jutting out into sea called a headland. the areas where the soft rock has eroded next to the headland are called bays.
how is a cave, arch ,stack and stump created?
a small crack in the rock that is widen by hydraulic action and abrasion.
as the waves grind away at the rock it begins to open up a cave.
the cave is widened by hydraulic action and eventually breaks through the headland to form an arch.
the arch becomes so wide that the roof can no longer supports its own weight and it collapses to form a stack
weathering occurs at the top of the stack and it is then undercut at the base until it collapses to form a stump.
how are wave cut notches and platforms created?
wave cut notches are created when erosional process act on the cliff more rapidly than sub- aerial process.overtime those processes act on the base of the cliff
