Facts about Weathering
Chemical weathering alters the chemical composition of the parent material, but mechanical weathering does not.
Sulfur dioxide (SO2) from volcanic eruptions or fossil fuels can become sulfuric acid when exposed to rainwater, which can cause solution weathering of the rocks on which it falls.
The most common form of biological weathering is the release of compounds (such as acids) secreted by trees, to break down elements such as aluminum and iron in the surrounding soil.
Chemical weathering involves changes in the chemical composition of rock, often leading to breakdown in its form.
Buildings made of limestone are particularly susceptible to weathering.
Formerly believed to be the dominant mode, frost wedging may still be a factor in the weathering of nonporous rock, although recent research has demonstrated it less important than previously thought.
A number of plants and animals may promote chemical weathering through the release of acidic compounds.
Weathering is the process of disintegration of rocks and soils and the minerals they contain through direct or indirect contact with the atmosphere.
Mechanical weathering involves the breakdown of rocks and soils through direct contact with atmospheric conditions such as heat, water, ice, and pressure.
Hydration is a form of chemical weathering that involves the strong attachment of H+ and OH- ions to the atoms and molecules of a mineral.
Chemical weathering involves the direct effect of atmospheric chemicals or biologically produced chemicals (also called biological weathering).
Thermal expansion—also known as onion-skin weathering, exfoliation, or thermal shock—is caused mainly by changes in temperature.
Hydroponics can be used in greenhouses, as well, to make the most use of the interior space.
Living organisms may contribute to mechanical weathering as well as chemical weathering (see 'biological' weathering below).
The breakdown products following chemical weathering of rock and sediment minerals, and the leaching out of the more soluble parts, can be combined with decaying organic material to constitute soil.
Another well-known example of animal-caused biotic weathering is by the bivalve mollusc known as a Piddock.
Carbonic acid is consumed by silicate weathering, resulting in more alkaline solutions because of the bicarbonate.
Weathering by salt crystallization is normally associated with arid climates, where strong heating causes rapid evaporation, leading to the formation of salt crystals.
Frost-induced weathering, although often attributed to the expansion of freezing water captured in cracks, is generally independent of the water-to-ice expansion.
One of the most well-known solution weathering processes is carbonation, the process in which atmospheric carbon dioxide leads to solution weathering.
Freeze-induced weathering action occurs mainly in environments where there is a lot of moisture, and temperatures frequently fluctuate above and below freezing point—that is, mainly alpine and periglacial areas.