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Chemical weathering takes place when water, oxygen, carbon dioxide, and other chemical substances react with rock to change its composition. These reactions convert some of the original primary minerals in the rock to secondary minerals, remove other substances as solutes, and leave the most stable minerals as a chemically unchanged resistate .
The difference in chemical weathering time can span millions of years. For example, quickest to weather of the common igneous minerals is apatite, which reaches complete weathering in an average of 10 5.48 years, and slowest to weather is quartz, which weathers fully in 10 8.59 years. [5]
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]
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The rate of weathering is sensitive to factors that change how much land is exposed. These factors include sea level , topography , lithology , and vegetation changes. [ 4 ] Furthermore, these geomorphic and chemical changes have worked in tandem with solar forcing, whether due to orbital changes or stellar evolution, to determine the global ...
The regolith of a region is the product of its long weathering history; leaching and dispersion are dominant during the initial phase of weathering under humid conditions. [1] Saprolites form in high rainfall regions which result in chemical weathering and are characterised by distinct decomposition of the parent rock's mineralogy. [5]
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. [4]
Ferrallitisation is the process in which rock is changed into a soil consisting of clay and sesquioxides, in the form of hydrated oxides of iron and aluminium.In humid tropical areas, with consistently high temperatures and rainfall for all or most of the year, chemical weathering rapidly breaks down the rock.