Erosion And Weathering Flashcards
Hydraulic action
Force of waves break against cliff.parts break off. Also as wave hits cliff air is compressed into cracks, forcing fragments of rock to also break off.
Attrition
Sand and pebbles constantly collide with each other as the waves move them. Making beach material smaller and more rounded.
Abrasion
During storm conditions. Waves pick up sand and pebbles and hurl them at cliffs. AKA sandblasting effect
Weathering
Break down of rocks by the action if weather,plants or chemical action.
Corrosion
Sea water slowly dissolves chalk and limestone. Increase size of cracks so erosion is more effective. Salt spray then goes into the cracks,evaporates, salt crystals form, force rocks apart.
Wetting/drying
Soft rocks (clay) , expand when wet and contract when dry. Weakens rocks, so erosion is more effective.
Freeze thaw
Water becomes trapped in a crack. Temp drops below freezing, the water freezes and expands puts pressure on the rocks,weakens and can shatter fragments of rock.
Biological
Burrowing animals, holes into cracks splitting the rock. Plants grow in cracks, push open cracks widening them, small pieces fall aware
Constructive wave
Smash is stronger than the backwash
Help build beaches
Long low waves
Less energy
Destructive waves
Backwash is stronger than swash Erodes cliffs rapidly Remove beach material Short steep waves More energy