Erosion

DefinitionsErosion- Breakdown and movement of materials by wind, water, or ice

Deposition- Drop off or settling of eroded materials

Wind ErosionGenerally occurs because there is no vegetation to hold down sand or soil

Increased wind speeds moves more materials and heavier materials

Wind ErosionProcesses

Saltation- Movement of sand-sized particles by skipping and bouncing in the wind’s direction

Deflation- Lifting and removal of fine sediment by wind

Saltation

Wind ErosionProcesses

Abrasion- grinding and wearing down of rock surfaces by other rock or sand

Deposition at dunes or loess

Sand Dune

Wave ErosionWaves continually break, picking up and depositing materials

Large storms with gusty winds create more wave energy leading to more erosion

Wave ErosionCreates sea cliffs and other coastal landforms

Deposition at beaches

Stream ErosionStreams begin as a channel, or path the water follows

The channel widens and deepens as rock and soil are moved

Stream ErosionRate is affected by gradient and discharge

Gradient- elevation over a certain distance

Discharge- Volume of water transported in a given time

Underground ErosionGroundwater dissolves certain types of rock

Caves form from dissolved limestone

Deposits are called dripstoneStalactite and stalagmite

Ice ErosionGlacier- Enormous mass of moving ice

Iceberg- Large piece of ice that breaks off a glacier into water

Calving- Process that forms icebergs

Ice ErosionThick glaciers move faster than thin glaciers

Glaciers with steeper slopes move faster

Ice ErosionTypes of glaciers

Alpine glaciers forms rugged features in mountains such as the Rocky Mountain and Alps

Continental glaciers smooth landscape by getting rid of existing landforms

Alpine Glacier erosion

Ice ErosionDeposition is called glacial drift

Stratified Drift occurs when sediment is sorted by water flowing from melting ice

Till Deposits are unsorted materials

GravityErosion by gravity is called mass movement

Examples are landslides, rock fall, mudflow, and creep (slow movement of materials downward)