Weathering•Process of disintegration of rock, minerals, and soil.

Two Types

1. Mechanical Weathering2. Chemical Weathering

Mechanical Weathering

1. Thermal2. Frost3. Pressure Release4. Hydraulic Action5. Salt Crystal Growth6. Biotic Growth7. Abrasion

Thermal Weathering

• The rock heats up and expands by day and cools and contracts by night, its outer layers undergo stress and break.

Frost• water gets in the cracks of rocks, freezes and

expands.• When the ice thaws, water can flow further into the

rock.

Pressure Release

• Overlying rocks are removed by erosion causing the underlying rocks to expand and fracture parallel to the surface.

Hydraulic Action

• Water from waves rush into cracks in the rock face. This process traps a layer of air in the crack, compressing it and weakening the rock.

Salt Crystal Growth

• Solutions seep into cracks and evaporate, leaving salt crystals behind. These crystals expand as they are heated up, exerting pressure on the rock.

Biotic Growth

• Seedlings sprout in a crack and plant roots exert pressure and provide a pathway for water.

Abrasion (Wind or Water)

• The wearing of rocks by friction, resulting from collisions among rock, sand and silt.

Chemical Weathering

• Solution (Carbonation)• Hydration• Hydrolysis• Oxidation• Sulfation• Biological

Solution (Carbonation)

• When rain combines with CO2 and forms carbonic acid, which reacts with limestone.

Hydration

• When rocks take up water, they increase in volume, creating stresses within the rock.

Hydrolysis

• A chemical weathering process affecting silicate minerals that results in dissolution of original mineral.

Oxidation

• Chemical oxidation of a variety of metals.• This process is better known as "rusting."

Sulfation

• The addition of Sulfur Dioxide to limestone produces gypsum, which is soluble and is easily dissolved and washed away.

Biological

• A number of plants and animals release of acidic compounds which breakdown rocks.