Influence of mineral weathering reactions on the chemical composition of soil water, Springs, and ground water, Catoctin Mountains, Maryland

1989 ◽  
Vol 3 (2) ◽  
pp. 185-202 ◽  
Author(s):  
B. G. Katz
Keyword(s):  
Chemical Composition ◽  
Ground Water ◽  
Soil Water ◽  
Mineral Weathering ◽  
Water Springs

Geochemical investigation of weathering processes in a forested headwater catchment: mass-balance weathering fluxes

2008 ◽  
Vol 72 (1) ◽  
pp. 65-69 ◽  
Author(s):  
B. F. Jones ◽  
J. S. Herman
Keyword(s):  
Chemical Composition ◽  
Surface Water ◽  
Ground Water ◽  
Mass Balance ◽  
Mineral Weathering ◽  
Subsurface Water ◽  
Balance Model ◽  
Compositional Variation ◽  
Weathering Profile ◽  
Solute Fluxes

AbstractGeochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and oxyhydroxides, and solute fluxes (Meunier and Velde, 1979). The chemical composition of the clay-mineral product is often ignored. However, in earlier investigations, the saprolitic weathering profile at the South Fork Brokenback Run (SFBR) watershed, Shenandoah National Park, Virginia, was characterized extensively in terms of its mineralogical and chemical composition (Piccoli, 1987; Pochatila et al., 2006; Jones et al., 2007) and its basichydrology. O’Brien et al. (1997) attempted to determine the contribution of primary mineral weathering to observed stream chemistry at SFBR. Mass-balance model results, however, could provide only a rough estimate of the weathering reactions because idealized mineral compositions were utilized in the calculations. Making use of detailed information on the mineral occurrence in the regolith, the objective of the present study was to evaluate the effects of compositional variation on mineral-solute mass-balance modelling and to generate plausible quantitative weathering reactions that support both the chemical evolution of the surface water and ground water in the catchment, as well as the mineralogical evolution of the weathering profile.

scholarly journals Peat decomposition – shaping factors, significance in environmental studies and methods of determination; a literature review

Geologos ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Danuta Drzymulska
Keyword(s):  
Chemical Composition ◽  
Literature Review ◽  
Ground Water ◽  
Environmental Conditions ◽  
Meteoric Water ◽  
Climatic Conditions ◽  
Review Of Literature ◽  
Forming Process ◽  
Physical And Chemical

Abstract A review of literature data on the degree of peat decomposition – an important parameter that yields data on environmental conditions during the peat-forming process, i.e., humidity of the mire surface, is presented. A decrease in the rate of peat decomposition indicates a rise of the ground water table. In the case of bogs, which receive exclusively atmospheric (meteoric) water, data on changes in the wetness of past mire surfaces could even be treated as data on past climates. Different factors shaping the process of peat decomposition are also discussed, such as humidity of the substratum and climatic conditions, as well as the chemical composition of peat-forming plants. Methods for the determination of the degree of peat decomposition are also outlined, maintaining the division into field and laboratory analyses. Among the latter are methods based on physical and chemical features of peat and microscopic methods. Comparisons of results obtained by different methods can occasionally be difficult, which may be ascribed to different experience of researchers or the chemically undefined nature of many analyses of humification.

Colloidal matter in water extracts from forest soils

2007 ◽  
Vol 4 (6) ◽  
pp. 424 ◽  
Author(s):  
Alexander Dreves ◽  
Nils Andersen ◽  
Pieter M. Grootes ◽  
Marie-Josée Nadeau ◽  
Carl-Dieter Garbe-Schönberg
Keyword(s):  
Organic Matter ◽  
Chemical Composition ◽  
Soil Water ◽  
Relative Proportion ◽  
Transport Processes ◽  
Total Charge ◽  
Dual Nature ◽  
Organic C ◽  
Water Extracts ◽  
Colloidal Fraction

Environmental context. Little is known about the proportion of tiny dispersed particles and true solutions in soil water although the distinction has a major influence on transport processes of organic matter, fertiliser and pollutants in soils and thus, e.g., on carbon storage, and its role in global warming. Our study has found a noticeable amount of tiny particles (range 17 nm to 1.0 μm) in filtered soil water, that have a different chemical composition and a lower bioavailability of their organic components in comparison to the soluble part. This significant occurrence and the ecological relevance of colloids for the transport and storage of soil constituents highlights the need to partition soil water content into ‘particulate’ and ‘dissolved’ since the access to soil pores determines particle transport. Abstract. Water-extracted organic matter (WEOM) is widely used as a surrogate for natural organic matter in soil water in the investigation of soil carbon dynamics. Information about the dissolved or colloidal nature of the organic matter is scarce since dissolved organic matter (DOM) is simply operationally defined by filtration: ‘DOM is what passes through the filter’. Water extracts of two topsoil horizons from both a deciduous (Steinkreuz) and a coniferous (Rotthalmünster) forest, located in Bavaria (Germany), were filtered through a 1-μm quartz filter and analysed regarding the amount of colloids in the range ~17 nm to 1.0 μm, the chemical composition and the radiocarbon concentration of both the colloidal and the dissolved fraction separated by high-speed centrifugation. Up to 13.9 wt-% of the total charge of the water extracts belongs to the colloidal fraction. The colloidal fraction has a higher relative proportion of metals and older organic C than the dissolved fraction. This demonstrates the dual nature of WEOM and the need for a more careful definition of DOM.

Did elevated atmospheric CO2alter soil mineral weathering?: an analysis of 5-year soil water chemistry data at Duke FACE study

2007 ◽  
Vol 13 (12) ◽  
pp. 2626-2641 ◽  
Author(s):  
NEUNG-HWAN OH ◽  
MICHAEL HOFMOCKEL ◽  
MICHAEL L. LAVINE ◽  
DANIEL D. RICHTER
Keyword(s):  
Water Chemistry ◽  
Soil Water ◽  
Mineral Weathering ◽  
Soil Mineral ◽  
Chemistry Data ◽  
Soil Water Chemistry
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