lesson 2- systems and processes Flashcards
what is erosion
wearing away of the earths surface by the mechanical action of glaciers, rivers and waves
what is fetch
the distance of open water over which the wind blows and helps determine the size and energy of the wave
what is mass movement
movement of material; downhill under the influence of gravity, e.g. slumping/rockslides
-not longshore drift
what is weathering
breaking down of rock near the earths surface due to biological (animals burrowing), mechanical (freeze thaw) and chemical (acid rain) action
what is the prevailing wind
wind from the predominant or most usual place
what is a constructive wave
-builds up beaches
-large swash and longer wave length
-weaker backwash, occurs when sea is calm
what is a destructive wave
-larger and more powerful- during storm (energy)
-stronger backwash than swash
-more frequent -> more water -> backwash increases/ moves up the beach -> erosion
what is a berm
a nearly horizontal plateau on the beach
-where sediment is deposited at the end of the swash when it runs out of energy, moves up the beach with a stronger swash
what is the longshore current/ littoral drift
current that flows parallel to the shore within the zone of breaking waves
what is the upwelling current
deep cold water rises towards surface near the coast
what are the 4 types of erosion
hydraulic action- trapped air is compressed by waves and hammers at cracks- occurs at headlands/ high impact points
Abrasion- rocks and other materials carried by the sea are picked up by strong waves and thrown against the coastline causing more material to be broken off
Attrition-when rocks that the sea is carrying knock against each other
Solution-when sea water dissolves certain types of rocks. In the UK, chalk and limestone cliffs are prone to this type of erosion.
what are the 4 types of transportation
Solution- smallest material floats
Suspension- slightly heavier
Saltation- too heavy to float- bounce
Traction- big rocks roll and erode against sea bed
