Erosion

Definitions Erosion- Breakdown and movement of materials by wind, water, or ice Deposition- Drop off or settling of eroded materials

Wind Erosion Generally occurs because there is no vegetation to hold down sand or soil Increased wind speeds moves more materials and heavier materials

Wind Erosion Processes 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 Erosion Processes Abrasion- grinding and wearing down of rock surfaces by other rock or sand Deposition at dunes or loess

Sand Dune

Wave Erosion Waves continually break, picking up and depositing materials Large storms with gusty winds create more wave energy leading to more erosion

Wave Erosion Creates sea cliffs and other coastal landforms Deposition at beaches

Stream Erosion Streams begin as a channel, or path the water follows The channel widens and deepens as rock and soil are moved

Stream Erosion Rate is affected by gradient and discharge Gradient- elevation over a certain distance Discharge- Volume of water transported in a given time

Underground Erosion Groundwater dissolves certain types of rock Caves form from dissolved limestone Deposits are called dripstone Stalactite and stalagmite

Ice Erosion Glacier- Enormous mass of moving ice Iceberg- Large piece of ice that breaks off a glacier into water Calving- Process that forms icebergs

Ice Erosion Thick glaciers move faster than thin glaciers Glaciers with steeper slopes move faster

Ice Erosion Types 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 Erosion Deposition is called glacial drift Stratified Drift occurs when sediment is sorted by water flowing from melting ice Till Deposits are unsorted materials

Gravity Erosion by gravity is called mass movement Examples are landslides, rock fall, mudflow, and creep (slow movement of materials downward)