Geochemical evaluation

Baker, E.G. (1967) A geochemical evaluation of petroleum migration and accumulation. In Fundamental Aspects of Petroleum Geochemistry. Nagy, B., Colombo, V. Eds., pp. 299-330, Elsevier, New York, New York. 

Reeve, A.S., Horesh, M., Warner, B. and Yates, M. (2001) Geochemical evaluation of sources for arsenic in ground water. Abstracts with Programs. The Geological Society of America, 33(1), 61. 

Cyr AJ, Currie BS, Rowley DB (2005) Geochemical evaluation of Fenghuoshan Group lacustrine carbonates, north-central Tibet implications for the paleoaltimetry of the Eocene Tibetan Plateau. J Geol 113 517-... 

Horstad, 1., Larter, S.R. and Mills, N. 1995. Migration of hydrocarbons in the Tampen Spur area, Norwegian North Sea a reservoir geochemical evaluation. Geol. Soc. Spec. Publ., 86 159-183. 

Eggenberger and Waber 1998, Cadmium in Seepage Waters of Landfills A Statistical and Geochemical Evaluation, Report of November 20, 1997 for the OECD Advisory Group on Risk Management Meeting, February 9-10,1998, Paris, France. 

Shotyk W (1995) Peat bog archives of atmospheric metal deposition geochemical evaluation of peat profiles, natural variations in metal concentrations. 

Horstad, L, Larter, S. R. Mills, N. 1995. Migration of Hydrocarbons in the Tampen Spur Area, Norwegian North Sea A Reservoir Geochemical Evaluation. Geological Society, London, Special Publications, 86, 159-183. 

Geochemical evaluation with quarrying operations planning. . 23... 

While these calculations provide information about the ultimate equilibrium conditions, redox reactions are often slow on human time scales, and sometimes even on geological time scales. Furthermore, the reactions in natural systems are complex and may be catalyzed or inhibited by the solids or trace constituents present. There is a dearth of information on the kinetics of redox reactions in such systems, but it is clear that many chemical species commonly found in environmental samples would not be present if equilibrium were attained. Furthermore, the conditions at equilibrium depend on the concentration of other species in the system, many of which are difficult or impossible to determine analytically. Morgan and Stone (1985) reviewed the kinetics of many environmentally important reactions and pointed out that determination of whether an equilibrium model is appropriate in a given situation depends on the relative time constants of the chemical reactions of interest and the physical processes governing the movement of material through the system. This point is discussed in some detail in Section 15.3.8. In the absence of detailed information with which to evaluate these time constants, chemical analysis for metals in each of their oxidation states, rather than equilibrium calculations, must be conducted to evaluate the current state of a system and the biological or geochemical importance of the metals it contains. 

These correlations mean that the HSAB principle could be a useful approach to evaluate the geochemical behavior of metals and ligands in ore fluids responsible for the formation of the epithermal vein-type deposits. Among the ligands in the ore fluids, HS" and H2S are the most likely to form complexes with the metals concentrated in the gold-silver deposits (e.g., Au, Ag, Cu, Hg, Tl, Cd), whereas Cl prefers to form complexes with the metals concentrated in the base-metal deposits (e.g., Pb, Zn, Mn, Fe, Cu, and Sn) (Crerar et al., 1985). 

Filey RH, Nguyen S, Campbell S, Bragg A and Grimm CA (1987) Evaluation of sample homogeneity for geochemical standard reference materials used in microanalysis. J Radioanal Nud Chem Artides 110 147-158. 

The geological sciences are involved in studying the naturally occurring materials of the earth and solar system (i) to understand the fimdamental processes of crustal formation on earth and solar system evolution, and (2) to evaluate the crustal materials of potential economic value to man. Prior to the 1930 s, analyses were carried out exclusively using classical analytical techniques, with detection limits on the order of o.oi-o.i % (mass fraction). The number of elements contained in any sample could be as extensive as the periodic table, but very few of these could be determined. The development of instrumental techniques revolutionized the analysis of geochemical samples, beginning in the 1930 s. 

Kane JS, Siems DF, Arbogast BF (1992) Geochemical exploration reference samples GXR-r to GXR-4 and GXR-6 evaluation of homogeneity based on high precision analyses. Geostds Newslett 16 45-54. 

Table 20.4 presents the partition and transformation processes known to occur in the near-surface environment along with the special factors that should be considered when evaluating data in the context of the deep-well environment. Geochemical processes affecting hazardous wastes in deep-well environments have been studied much less than those occurring in near-surface environments (such as soils and shallow aquifers). Consequently, laboratory data and field studies for a particular substance may be available for near-surface conditions, but not for deep-well conditions. 

Many factors and processes must be considered when evaluating the movement of deep-well-injected hazardous wastes. Four factors are relevant to geochemical characteristics ... 

My first attempt to calculate the time history of a geochemical system (Section 2.3) used the obvious approach (the direct Euler method) of evaluating the time derivatives and stepping forward. But it was not sue-... 

Calculating a geochemical model provides not only results, but uncertainty about the accuracy of the results. Uncertainty, in fact, is an integral part of modeling that deserves as much attention as any other aspect of a study. To evaluate the sources of error in a study, a modeler should consider a number of questions ... 

This choice of basis follows naturally from the steps normally taken to study a geochemical reaction by hand. An aqueous geochemist balances a reaction between two species or minerals in terms of water, the minerals that would be formed or consumed during the reaction, any gases such as O2 or CO2 that remain at known fugacity as the reaction proceeds, and, as necessary, the predominant aqueous species in solution. We will show later that formalizing our basis choice in this way provides for a simple mathematical description of equilibrium in multicomponent systems and yields equations that can be evaluated rapidly. 

Helgeson, H. C., 1968, Evaluation of irreversible reactions in geochemical processes involving minerals and aqueous solutions, I. Thermodynamic relations. Geochimica et Cosmochimica Acta 32, 853-877. 

Levson, V.M. 2001. Regional till geochemical surveys in the Canadian Cordillera sample media, methods, and anomaly evaluation. In McClenaghan, M.B., Bobrowsky, P.T., Hall, G.E.M. Cook, S.J. (eds). Drift Exploration in Glaciated Terrain, Geological Society, Special Publication, 185, 45-68. 

The objective of this paper is to evaluate the dominant geochemical mechanisms of the Holocene sandy aquifers so as to... 

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