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Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs in situ (on-site, with little or no movement), and so is distinct from erosion , which involves the transport of rocks and minerals by agents such as ...
Haloclasty (also called salt expanding) is a type of physical weathering caused by the growth and thermal expansion of salt crystals. The process starts when saline water seeps into deep cracks and evaporates depositing salt crystals. When the rocks are then heated, the crystals will expand putting pressure on the surrounding rock which will ...
Because weathering rate is a function of saturation of the dissolving mineral in solution (decreasing to zero in fully saturated solutions), some have suggested that lack of rainfall may limit terrestrial enhanced weathering, [19] although others [20] suggest that secondary mineral formation or biological uptake may suppress saturation and ...
Phosphorus is used to make nucleic acids and the phospholipids that comprise biological membranes. Sulfur is critical to the three-dimensional shape of proteins. The cycling of these elements is interconnected. For example, the movement of water is critical for leaching sulfur and phosphorus into rivers which can then flow into oceans.
For example, three species of land snails in the genus Euchondrus in the Negev desert are noted for eating lichens growing under the surface limestone rocks and slabs (endolithic lichens). The grazing activity of these ecosystem engineers disrupts the limestone, resulting in the weathering and the subsequent formation of soil. [113]
Another important example concerns the study of airborne allergens (such as pollens and aerosols) and their impact on individuals: weather conditions can favor or hinder the release as well as the transport and deposition of these allergens, sometimes severely affecting the well-being of sensitive populations.
Reverse weathering is often found in river deltas as these systems have high sediment accumulation rates and are observed to undergo rapid diagenesis. [18] The formation of silicate clays removes reactive silica from the pore waters of sediment, increasing the concentration of silica found in the rocks that form in these locations.
Several Lecidea species contribute to the weathering processes on rock surfaces, known as pedogenesis. These saxicolous species extend their hyphae into rock crevices, gradually detaching, incorporating, and expelling rock flakes. Lecidea auriculata, an example of a euendolithic lichen, actively bores into and inhabits the mineral matrix within ...