Actions That Change Earth’s Surface

• The physical or chemical processes that break down (wear away) rocks

• Agents of weathering: wind, water, ice, gravity, plants and animals (biologic)

• Mechanical weathering: ice wedging, root pry, abrasion (grinding), exfoliation, animals, and thermal expansion

• Chemical weathering: oxidation (iron + oxygen + water = rust), acidic precipitation (from burning fossil fuels: sulfur, carbon dioxide, and nitrogen), plant acids (lichens and mosses) carbonic acids (marble and limestone), hydrolysis (feldsapar to clay), and dissolution (water)

The type of rock: mineral compositionSurface area: smaller rocks have a greater

surface area (consider volume) and weather faster

Climate (temperature and precipitation): hot/warm and wet/humid weather fastest

Erosion is the transport (movement) of weathered rocks and sediment from one place to another.

Erosion is usually gradual…

Humans can speed it up.

WindWaterWavesGlaciers (ice)Gravity (mass

movement, mass wasting)

What goes up must come down.

What is carried must be… dropped.

Deposition occurs when agents of erosion deposit (lay down, drop) sediment.

Sand bars Longshore drift

Large mass of moving ice and snow

Plucking Abrasion

Rapid Mass Wasting…

Landslide Mudflow

Creep SlumpSlow mass wasting…

Deflation Sand dunes

Poor soil conservation…

Running waterLoad deposits

Delta Alluvial fan

Stalactites and stalagmites