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Soil Pollution and Its Control
Published in Danny D. Reible, Fundamentals of Environmental Engineering, 2017
Soils develop via two basic mechanisms, deposition by winds (aeolian soils) and water (alluvial soils) or by weathering of parent bedrock. Soils that form via deposition processes tend to be layered. For example, during high water flow conditions only coarser material may settle while under low flow conditions settling of finer grained material may occur. These layers of differing soil type exhibit different permeabilities and result in the development of preferential flow channels. Soils formed by weathering of bedrock may be layered as well but often not as distinctly. The fine clays in this soil can be washed out of upper layers (the process of eluviation) and washed in to lower layers (the process of illuviation). The upper layers of soil typically contain the bulk of the organic matter in soil due to the presence of decaying plant and animal matter. A surface soil might contain 2 to 4% organic matter although peat and some other high organic matter surface materials may contain considerably more. In deeper soils, the organic matter may be less than a few tenths of a percent.
Weathering and Soils
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
In all but the driest environments, rainwater and snowmelt infiltrate soil and can dissolve soluble soil components and carry them downwards. This process, shown in Figure 11.30, of dissolution and transportation is called eluviation. If the dissolved material is deposited in lower soil levels, the process of transportation and deposition is called illuviation. Sometimes, flowing groundwater removes dissolved material from a soil column completely, by a process called leaching.
Geotechnical properties of residual soils from the North-east of Argentina
Published in International Journal of Geotechnical Engineering, 2019
Gustavo O. Bogado, Hugo O. Reinert, Franco M. Francisca
Near the surface soils suffer pedogenic processes that promote the addition, loss, and transformation of the material. The main processes are eluviation–illuviation that involves the loss and addition of material, respectively, leaching that removes soluble salts and lateralisation (Vaz 1996). Gidigasu (2012) indicates that lateralisation involve the leaching, under appropriate drainage conditions, of combined silica and bases and a relative accumulation of oxides and hydroxides of sesquioxides (mainly AlO3, Fe2O3 and TiO2).
Subaerial disconformities, microkarst and paleosols in Ordovician limestones at Bowan Park and Cliefden Caves, New South Wales, and their geoheritage significance
Published in Australian Journal of Earth Sciences, 2019
V. Semeniuk, I. G. Percival, M. Brocx
Indurated marine carbonate sediments (limestones) beneath and at subaerial disconformities at local to regional scale are characterised by the features listed below:microkarst and macrokarst features (surface and subsurface solutional surfaces);fossil moulds and irregular solution cavities, commonly with internal sediment (mainly crystal silt of Dunham [1969] and pellets);small- to large-scale depressions, cracks, fissures and irregular surfaces filled with marine sediment or soil;fracture and veining;vadose-water illuviation of fine-grained sediment (mainly crystal silt and pellets);vadose-water illuviation of exotic sediment (such as eolian dust);geochemical alteration and adjustments from the surface downwards (e.g. bleaching);erosional surfaces at the disconformity with truncation of structural, fossil and petrographic features at the disconformity, with the disconformity being low-angle bedding intersections to bedding-parallel surfaces;regional erosional pinch-out of beds;iron-oxide staining of disconformity surfaces; andsilicification, including silicification of fossils.