Erosion

1. Erosion Erosion - process of removing Earth materials from their original sites through weathering and transport

2. Agents of Erosion • Gravity - the natural force that pulls objects toward the center of the earth. • Water –flowing water carries sediments down stream • Wind – had the power to transport and deposit sediment. • Glacial/Ice – Massive sheets of ice picks up sediments which scrapes the land underneath

3. GRAVITY Mass Wasting – the downhill movements of masses of rock and soil • Landslide - Can be suddenly or gradually moving tons of rock. • Rock Fall – rocks fall downhill freely down cliffs of mountainside • Rockslide – large mass of rock slides downhill sometimes 100s MPH, sometimes triggered by earthquakes. • Mudflow – mixture of rock, soil, plants (debris) and large amounts of water • Slumps/Creep – less dramatic events, • Slump – slide of loose debris moving as a single unit (unstable slopes) • Creep – slowest movement of mass wasting, too slow to be seen, fence poles moving downward or leaning

4. WATER • Running water is the major force shaping the landscape over most of the earth. • Water soaks/seeps into the ground forming underground caverns and sinkholes. • Moving water creates valleys, floodplains, streams, and deltas.

5. WIND • Sand dunes – mound of sand built up by wind • Loess – deposits of fine wind blown sediment (dust), can be valuable because it forms good soil for growing crops. • Desert Pavement – wind removes all loose soil and sediments leaving behind just layer of stones and gravel, looking like cobblestone pavement, too big to be moved by wind.

6. GLACIAL/ICE • Alpine Glaciers – forms in mountains and flow down through the valleys, causing erosion, can change a V-shaped mountain valley into a U shaped valley with a wider flatter bottom • Glacial movement leaves abrasion lines on rock. • Creates depressions which can become lakes (Great Lakes of North America – Huron, Ontario, Micigan, Erie, Superior)