Weathering
•Process of disintegration of rock,minerals, and soil.
Two Types
1. Mechanical Weathering
2. Chemical Weathering
Mechanical Weathering
1.Thermal
2.Frost
3.Pressure Release
4.Hydraulic Action
5.Salt Crystal Growth
6.Biotic Growth
7.Abrasion
Thermal Weathering
•The rock heats up and expands by day andcools and contracts by night, its outer layersundergo stress and break.
Frost
•water gets in the cracks of rocks, freezes andexpands.
•When the ice thaws, water can flow further intothe rock.
Pressure Release
•Overlying rocks are removed by erosioncausing the underlying rocks to expand andfracture parallel to the surface.
Hydraulic Action
•Water from waves rush into cracks in the rockface. 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 crystalsexpand as they are heated up, exertingpressure on the rock.
Biotic Growth
•Seedlings sprout in a crack and plant rootsexert pressure and provide a pathway forwater.
Abrasion (Wind or Water)
•The wearing of rocks by friction, resultingfrom collisions among rock, sand and silt.
Chemical Weathering
•Solution (Carbonation)
•Hydration
•Hydrolysis
•Oxidation
•Sulfation
•Biological
Solution (Carbonation)
•When rain combines with CO2 and formscarbonic acid, which reacts with limestone.
Hydration
•When rocks take up water, they increase involume, creating stresses within the rock.
Hydrolysis
•A chemical weathering process affectingsilicate minerals that results in dissolution oforiginal mineral.
Oxidation
•Chemical oxidation of a variety of metals.
•This process is better known as "rusting."
Sulfation
•The addition of Sulfur Dioxide to limestoneproduces gypsum, which is soluble and iseasily dissolved and washed away.
Biological
•A number of plants and animals release ofacidic compounds which breakdown rocks.
