Erosion

Through Wind, Water, Glaciers, and Gravity

Erosion

• Erosion is the the transportation of weathered material by a mobile agent, such as water, wind, gravity or ice (glaciers).

• In other words, Erosion MOVES sediments.

Wind Erosion

• Deflation: lifting and removal of lose particles such as clay and silt.

• Abrasion: is the mechanical scraping of a rock surface by friction between rocks and moving particles during their transport.

Loess and Sand Dunes

• Loess is wind blown angular silt that formed from weathering by glaciers or volcanic ash.

• Sand dunes form on beaches and in deserts when blowing sand is obstructed.

Sand Dunes

• Dunes can tell you which way the wind was blowing.

• Windward: Direction wind is blowing from (shallow slope)

• Leeward: Steep slope where sand is deposited.

Wind Break-Line of trees used to prevent wind erosion.

Glacial Erosion

• Glacier: A thick, flowing ice mass that forms over the land from the accumulation, compaction, and recrystallization of snow. Glaciers move!!!

Glacial Erosion

• Glaciers bring rocks and debris with them when they move and these rocks are left behind when the glacier melts.

• Glacial sediment is called Till.

• Till is poorly sorted.• Wind-blown glacial silt

is called loess.

Glacial Erosion

Erratic-Large boulder deposited by a melting glacier.

U-Shaped Valley carved by a glacier

Cirque- A steep, bowl structure