Search results
Results from the WOW.Com Content Network
Physical weathering, also called mechanical weathering or disaggregation, is the class of processes that causes the disintegration of rocks without chemical change. Physical weathering involves the breakdown of rocks into smaller fragments through processes such as expansion and contraction, mainly due to temperature changes.
Chemical weathering of rocks that leads to the formation of Liesegang rings typically involves the diffusion of oxygen in subterranean water into pore space containing soluble ferrous iron. [7] Liesegang rings usually cut across layers of stratification and occur in many types of rock, some of which more commonly include sandstone and chert . [ 3 ]
Case hardening is a weathering phenomenon of rock surface induration.It is observed commonly in: felsic alkaline rocks, such as nepheline syenite, phonolite and trachyte; pyroclastic rocks, as pyroclastic flow deposit, fine air-fall deposits and vent-filling pyroclastic deposits; sedimentary rocks, as sandstone and mudstone.
Denudation incorporates the mechanical, biological, and chemical processes of erosion, weathering, and mass wasting. Denudation can involve the removal of both solid particles and dissolved material. These include sub-processes of cryofracture, insolation weathering, slaking , salt weathering, bioturbation , and anthropogenic impacts.
The inorganic cycle begins with the production of carbonic acid (H 2 CO 3) from rainwater and gaseous carbon dioxide. [6] Due to this process, normal rain has a pH of around 5.6. [ 7 ] Carbonic acid is a weak acid , but over long timescales, it can dissolve silicate rocks (as well as carbonate rocks).
[1] [2] Climate is a key extrinsic variable, controlling the water to rock ratio, pH, and alkalinity, all of which impact the rate of weathering. [1] The Goldich dissolution series concerns intrinsic mineral qualities, which were proven both by Goldich as well as preceding scientists to also be important for constraining weathering rates.
This page was last edited on 29 October 2015, at 00:18 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.
Slow rates of decomposition leads to large amounts of fulvic acid, greatly enhancing chemical weathering. The downward percolation, in conjunction with chemical weathering leaches Mg, Fe, and aluminium (Al) from the soil and transports them downward, a process known as podzolization. This process leads to marked contrasts in the appearance and ...