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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.
Spheroidal weathering of a dolerite dyke, Pilbara, Western Australia. Spheroidal weathering is a form of chemical weathering that affects jointed bedrock and results in the formation of concentric or spherical layers of highly decayed rock within weathered bedrock that is known as saprolite.
Tropical weathering (laterization) is a prolonged process of chemical weathering which produces a wide variety in the thickness, grade, chemistry and ore mineralogy of the resulting soils. [10]: 3 The initial products of weathering are essentially kaolinized rocks called saprolites. [11]
Clay minerals most commonly form by prolonged chemical weathering of silicate-bearing rocks. They can also form locally from hydrothermal activity. [ 16 ] Chemical weathering takes place largely by acid hydrolysis due to low concentrations of carbonic acid , dissolved in rainwater or released by plant roots.
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]
In addition to chemical and physical weathering of hydraulic action, freeze-thaw cycles, and more, there is a suite of processes which have long been considered to contribute significantly to bedrock channel erosion include plucking, abrasion (due to both bedload and suspended load), solution, and cavitation.
The use of weathering rinds in relative dating is widely used in Arctic, Antarctic, and alpine regions and in the correlation of glacial moraines and tills and fluvial sediments and terraces. [6] [7] [8] In addition, weathering rinds have been used to determine the absolute amount of time gravel-size rock has been exposed to the weathering ...
Many explanations have been proposed for the origin of tafoni. They include marine abrasion; wind corrosion; mechanical weathering resulting from short-term temperature variations; chemical weathering of the interior of the rock (core-softening) under a protective crust (case-hardening) followed by mechanical removal of the softened material; biogeochemical weathering by lichens; temperature ...