Crust, soil

Rocks Conti- nental crust Soils Sediments ... 

We begin with a discussion of the most common minerals present in Earth s crust, soils, and troposphere, as well as some less common minerals that contain common environmental contaminants. Following this is (1) a discussion of the nature of environmentally important solid surfaces before and after reaction with aqueous solutions, including their charging behavior as a function of solution pH (2) the nature of the electrical double layer and how it is altered by changes in the type of solid present and the ionic strength and pH of the solution in contact with the solid and (3) dissolution, precipitation, and sorption processes relevant to environmental interfacial chemistry. We finish with a discussion of some of the factors affecting chemical reactivity at mineral/aqueous solution interfaces. 

In the next three subsections, we discuss the most important minerals in Earth s crust, soils, and atmosphere, and explore some of the basic concepts that help guide our thinking about their interactions with water, aqueous metal ions, organic matter, microbial organisms, and atmospheric and soil gases. 

Environmental Samples. Since environmental samples such as airborne particles and sediments originate mainly from constituents of the crust (soils and rocks) and generally contain a high percentage of iron, they can be characterized by TFe Mossbauer spectroscopy. A fairly comprehensive review article has been pubhshed recently on iron oxides and hydroxides in soils (22). 

Cultivation has some effect on soil aeration but less than might be expected. Domby and Kohnke (1956), for example, showed that surface crusts on a silt loam restricted gaseous diffusion only at low moisture tensions. The wetter the soil, the greater was the influence of crusts on diffusion. They state that except during a pe lriod of complete sealing, however, crusted soils actually may permit more rapid diffusion and be better aerated than mulched or other uncrusted soils, because of differences in moisture content. ... 

Although primarily paleolimnologically based in its development, the above approach to SCP source apportionment is applicable to particles extracted from any depositional sink including atmospheric collectors, building stone crusts, soils and leaves. 

Potassium in the form of K ion is a key element in the enzymatic control of the interchange of sugars, starches, and cellulose. Although potassium is the seventh most abundant element in Earth s crust, soil used heavily in crop... 

Six non-physico-chanical properties have been used to predict cation toxicity (Table 5.21). These include serum concentrations, calmodulin activity, freshwater concentrations, abundance in the earth s crust, soil concentrations, and elemental composition of soils and plants. 

Southard, R. J., Shainberg, I. Singer, M. J. (1988). Influence of electrolyte concenti ation on the micromorphology of artificial depositional crust. Soil Science Society of America Journal, 145, 278-288. 

Karamitros DK, Bouckovalas GD, Chaloulos YK (2013) Seismic settlement of shallow foundations on liquefiable soil with a clay crust. Soil Dyn Earthq Eng 46 64—76... 

Prevention of Soil Crusting. Acid-based fertilizers such as Unocal s N/Furic (a mixture of urea with sulfuric acid), acidic polymers such as FMC s Spersal (a poly(maleic acid) derivative originally developed to treat boiler scale) (58), the anionic polyacrylamides described previously, as weU as lower molecular weight analogues such as Cytec s Aerotil L Soil Conditioner, have all been used successfully in at least some circumstances to prevent the formation of soil cmsts. It is difficult to prove benefits in the laboratory, and field tests may give variable results depending on local weather conditions. 

From their focal point to the earth s surface seismic w-aves travel through the earth s crust and the soil. The stratification of soil, i.e. the earth s layers above the crust, plays an important role, as the intensity and frequencies of an earthquake, as felt on the earth s surface, will depend upon the type of soil strata. 

As indicated above, the bicarbonate ion inhibits the process, which does not occur, therefore, in many supply waters attack is most likely in waters which by nature or as a result of treatment have a low bicarbonate content and relatively high chloride, sulphate or nitrate content. The number of points of attack increases with the concentration of aggressive anions and ultimately slow general corrosion may occur. During exposure of 99-75% tin to sea-water for 4 years, a corrosion rate of 0-0023 mm/y was observed . Corrosion in soil usually produces slow general corrosion with the production of crusts of oxides and basic salts this has no industrial importance but is occasionally of interest in archaeological work. 

Silicon is the second most abundant element in the earth s crust. It occurs in sand as the dioxide Si02 and as complex silicate derivatives arising from combinations of the acidic oxide Si02 with various basic oxides such as CaO, MgO, and K20. The clays, micas, and granite, which make up most soils and rocks, are silicates. All have low solubility in water and they are difficult to dissolve, even in strong acids. Silicon is not found in the elemental state in nature. 

The sediment reservoir (1) represents all phosphorus in particulate form on the Earth s crust that is (1) not in the upper 60 cm of the soil and (2) not mineable. This includes unconsolidated marine and fresh water sediments and all sedimentary, metamorphic and volcanic rocks. The reason for this choice of compartmentalization has already been discussed. In particulate form, P is not readily available for utilization by plants. The upper 60 cm of the soil system represents the portion of the particulate P that can be transported relatively quickly to other reservoirs or solubilized by biological uptake. The sediment reservoir, on the other hand, represents the particulate P that is transported primarily on geologic time scales. 

Compounds of silicon with oxygen are prevalent in the Earth s crust. About 95% of crastal rock and its various decomposition products (sand, clay, soil) are composed of silicon oxides. In fact, oxygen is the most abundant element in the Earth s crast (45% by mass) and silicon is second (27%). In the Earth s surface layer, four of every five atoms are silicon or oxygen. 

UNSAT-H sets infiltration equal to the precipitation rate unless the surface soil becomes saturated. It does not simulate the soil crust that develops on the soil surface however, the user may describe a constant soil crust as a thin surface soil layer. It does not simulate runoff explicitly 80 however, it assigns excess precipitation that does not infiltrate into the soil as surface runoff. 

Minerals are the most abundant type of solid matter on the crust of the earth they are homogeneous materials that have a definite composition and an orderly internal structure. Minerals make up most of the bulk of rocks, the comminuted particles of sediments, and the greater part of most soils. Over 3000 minerals have been identified, and new ones are discovered each year. Only a few hundred, however, are common most of the others, such as, for example, the precious stones, are difficult to find (Ernst 1969). Table 3 lists common minerals and mineraloids. Many schemes have been devised for classifying the minerals. In the scheme presented in Table 4, minerals are arranged in classes according to their increasing compositional chemical complexity. 

One of the characteristic features of Reg soils is the vesicular nature of the uppermost soil horizon. The size distribution of the vesicles is up to a few mm in diameter. Similar vesicular structures were also observed in lithosols and takyr-like alluvial soils and were always associated with the presence of stones or thin, hard crusts that sealed the soil surface. It forms mostly through accumulation of aeolian dust (McFadden et al., 1998). 

Trapped air and expansion of heated air in the soil are the cause of vesicle formation. When the air is driven out by infiltrating rain or floodwater, and cannot escape downwards, it escapes through the upper surface of the soil. When the soil surface is neither covered by stone, nor sealed by crusts, the vesicles are of a temporary nature only. When,... 

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