Weathering of silicates, chemical

Hochella, M. F. Jr. and Banfield, J. F. (1995). Chemical weathering of silicates in nature A microscopic perspective with theoretical considerations. In "Chemical Weathering Rates of Silicate Minerals" (A. F. White and S. L. Brantley, eds), pp. 353 06. Mineralogical Society of America Washington, DC, Reviews in Mineralogy 31. 

The chemical weathering of silicates and carbonates occurs through hydrolysis... 

Fieldes, M. and Swindale, L. D., The chemical weathering of silicates in soil formation,... 

Correns, C. The experimental chemical weathering of silicates. Clay Mineral. Bull. 249-265 (1961). 

Bricker O. P., Godfrey A. E., and Cleaves E. T. (1968) Mineral-water interactions during the chemical weathering of silicates. In Trace Inorganics in Water, Advances in Chemistry Series 73 (ed. R. E. Gould). American Chemical Society, Washington, DC, pp. 128-142. 

Drever J. I. and Zobrist J. (1992) Chemical weathering of silicate rocks as a function of elevation in the southern Swiss Alps. Geochim. Cosmochim. Acta 56, 3209-3216. 

Loughnan (1969) discussed the solubility in relation to pH of some of the common products of chemical weathering of silicate minerals, In general, the hydroxides of Na, K and Ca are soluble at all pH s, and Mg(OH)2 is soluble at pH < 10. Aluminium oxide is soluble at pH s < 4 and >10, whereeis SiOj is slightly soluble at pH < 9 and increasingly soluble at higher pH values. Titanium hydroxide is soluble at pH < 5, but TiOz is soluble only at pH < 2. The hydroxide of trivalent iron is soluble only below pH 2.5, but Fe(OH)2 is soluble below about pH 8.5. 

Hochella MF, Banfield JF (1995) Chemical weathering of silicates in nature a microscopic perspective with theoretical considerations. Rev Mineral 31 353-406 Jamnik J, Maier J (1997) Transport across botmdary layers in ionic crystals. Chem Phys 101 23-40 Khachaturyan AG (1983) Theory of Stractrrral Transformations in Solids. Wiley, New York, 574 p Krivoglaz MA (1969) Theory of X-ray and thermal nention scattering by real crystals. Plenum, New York, 405 p... 

Chemical weathering of silicates was observed in a microcosm study conducted in situ in a petroleum-contaminated aquifer. Enhanced mineral weathering was attributed to the colonization of mineral surfaces by indigenous... 

Loughman, F. C. (1969). Chemical Weathering of Silicate Minerals. Elsevier, New York, 154 pp. 

Livingstone, D. A. 1963. Chemical composition of rivers and lakes. 6th ed. U.S. Geol, Survey Prof. Paper 440-G. Loughnan, E C. 1969, Chemical weathering of silicate minerals. New York Amer. Elsevier Publ. Co, Inc. 

With the exception of cation exchange on clay minerals, none of the previous workers considered the role of chemical weathering of silicate minerals in the chemical evolution of groundwater on the plains. 

Johnson, N. M., G. E. Likens, F. H. Borman, and R. S. Pierce (1968). Rate of chemical weathering of silicate minerals in New Hampshire. Geochim. Cosmochim. Acta 32, 531-545. 

Mineral-Water Interaction During the Chemical Weathering of Silicates... 

The Sr/ Sr ratio of the brine in Don Juan Pond measured by Jones (1969) was confirmed by Friedman et al. (1995) who reported values of 0.7185 for brine collected on January 10, 1975 0.7186 for crystals of antarcticites collected in November of 1973 and 0.7187 for interstitial brine from sediment at a depth of 10.8 m. They also reported that the average Sr/ Sr ratio of glacial meltwater that is discharged into Don Juan Pond is 0.7163 0.0009 and that the average strontium concentration of the meltwater is only 0.086 0.011 ppm. Evidently, the strontium in the meltwater that flows into Don Juan Pond is derived by chemical weathering of silicate minerals in the soil west of the pond and marine strontium is not detectable in the water of the tributary streams. The hterature containing information relevant to the study of Don Juan Pond is listed in Appendix 19.9.4. 

The Sr/ Sr ratio of strontium leached from the soil in the vicinity of Lake Bonney (0.7136) is similar to the Sr/ Sr ratio of strontium in the lake (Jones and Faure 1968, 1978). The brine discharged by the Taylor Red Cone at the terminus of the Taylor Glaeier also has an Sr/ Sr ratio of 0.7136. These results suggest that the salts dissolved in Lake Bonney are largely derived by chemical weathering of silicate minerals in the soil in the Bonney watershed. Therefore, the provenance of salts in Lake Bonney closely resembles the derivation of salts in Lake Vanda. The Sr/ Sr ratios of water in the lakes of Taylor Valley and in soil salts decrease in Fig. 19.45 from Lake Bonney to the eoast of McMurdo Sound due to the increasing abundanee of marine strontium (Jones and Faure 1978). 

The consumption of atmospheric carbon dioxide by chemical weathering of silicate minerals counteracts global warming caused by increases in the concentration of carbon dioxide in the atmosphere and sets up a feed-back mechanism that causes cyclical variations in the global climate. Nezat et al. (2001) explained it this way ... 

The strontium in each meltwater stream in Taylor Valley is derived by chemical weathering of the silicate minerals in the soil and contains varying proportions of marine strontium that is transported into Taylor Valley by the wind in the form of snow flakes and atmospheric particulates. The Sr/ Sr ratios of the lakes in Fig. 19.49 decrease from west to east in Taylor Valley from Lake Bonney (0.71187, west 0.71204, east) to Lake Hoare (0.71057), and to Lake Fryxell (0.70895). This trend is caused by the increasing abundance of marine strontium with decreasing distance from the coast that is also evident in Fig. 19.45. The elevated Sr/ Sr ratios in the lakes and tributaries in the central and western parts of Taylor Valley confirm that most of the strontium originated by chemical weathering of silicate minerals in the soil. 

This simple model is applied to chemical weathering of silicates caused by the interaction of rainwater penetrating permeable rocks downward to interpret Goldich s weathering series. 

Fieldes, M., and L. D. Swindale, 1954. Chemical weathering of silicate in soil formation. New Zealand J, Sci, Tech, 36 140. 

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