Geochemistry modelling

Taken from W. S. Fyfe, Geochemistry, Oxford University Press, 1974, with some modifications and additions to incorporate later data. The detailed numbers are subject to various assumptions in the models of the global distribution of the various rock types within the crust, but they are broadly acceptable as an indication of elemental abundances. See also Table 1 in C. K. J0RGENSEN, Comments Astrophys. 17, 49-101 (1993). 

Kaul, L. W. and Froelich, P. N. Jr. (1984). Modeling estuarine nutrient geochemistry in a simple system. Geochim. Cosmochim. Acta 48,1417-1434. 

Reed, M.H. and Spycher, N.F. (1985) Boiling, cooling and oxidation to epithermal systems. A numerical modeling approach. In Berger, B.R. and Bethke, P.M. (eds.). Geology and Geochemistry of Epithermal System. Reviews in Economic Geology, 2, 249-272. 

Langmuir D (1997) Aqueous Environmental Geochemistry. Prentice Hall, New Jersey, USA Latham AG, Schwarcz HP (1987a) On the possibihty of determining rates of removal of uranium from crystalline igneous rocks using U-series disequilibria - 1 a U-leach model, and its apphcabihty to whole-rock data. Appl Geochem 2 55-65... 

Figure 4. Modeled U-series date profiles across a 10 ky bone according to the D-A model under constant conditions. The dates are calculated using the closed system assumption. The parameter D/R is the diffusion-adsorption parameter and is related to the water content of the soil, the state of preservation of the bone and aspects of the geochemistry of the burial environment. After Pike et al. (2002). [Used by permission of Elsevier Science, from Pike et al. (2002), Geochim Cosmochim Acta, Vol. 66, Fig. 2, p. 4275.]...

When they calculated the species distribution in seawater, Garrels and Thompson (1962) were probably the first to apply chemical modeling in the field of geochemistry. Modern chemical analyses give the composition of seawater in terms of... 

The ion exchange model is most commonly applied in geochemistry to describe the interaction of major cationic species with clay minerals, or the clay mineral fraction of a sediment it has also been applied to zeolites and other minerals, and to ions besides the major cations (e.g., Viani and Bruton, 1992). As the name suggests, the model treats not the sorption and desorption of a species on the surface and in the interlayers of the clay, but the replacement of one ion there by another. 

Unfortunately, no software techniques exist currently to automatically search for additional roots. Instead, modelers must rely on their understanding of geochemistry to demonstrate uniqueness to their satisfaction. Activity-activity diagrams such as those presented in Figures 12.1-12.3 are the most useful tools for identifying additional roots. 

In this chapter we consider the problem of the kinetics of the heterogeneous reactions by which minerals dissolve and precipitate. This topic has received a considerable amount of attention in geochemistry, primarily because of the slow rates at which many minerals react and the resulting tendency of waters, especially at low temperature, to be out of equilibrium with the minerals they contact. We first discuss how rate laws for heterogeneous reactions can be integrated into reaction models and then calculate some simple kinetic reaction paths. In Chapter 26, we explore a number of examples in which we apply heterogeneous kinetics to problems of geochemical interest. 

Reaction kinetics enter into a geochemical model, as we noted in the previous chapter, whenever a reaction proceeds quickly enough to affect the distribution of mass, but not so quickly that it reaches the point of thermodynamic equilibrium. In Part I of this book, we considered two broad classes of reactions that in geochemistry commonly deviate from equilibrium. 

We choose as a first example the evaporation of spring water from the Sierra Nevada mountains of California and Nevada, USA, as modeled by Garrels and Mackenzie (1967). Their hand calculation, the first reaction path traced in geochemistry (see Chapter 1), provided the inspiration for Helgeson s (1968 and later) development of computerized methods for reaction modeling. 

In this chapter, we consider how to construct quantitative models of the dynamics of microbial communities, building on our discussion of microbial kinetics in Chapter 18. In our modeling, we take care to account for how the ambient geochemistry controls microbial growth, and the effect of the growth on geochemical conditions. 

Baccar, M. B. and B. Fritz, 1993, Geochemical modelling of sandstone diagenesis and its consequences on the evolution of porosity. Applied Geochemistry 8, 285-295. 

Davis, J. A. and D. B. Kent, 1990, Surface complexation modeling in aqueous geochemistry. In M. F. Hochella and A. F. White (eds.), Mineral-Water Interface Geochemistry. Reviews in Mineralogy 23, 177-260. 

May, H., 1992, The hydrolysis of aluminum, conflicting models and the interpretation of aluminum geochemistry. In Y. K. Kharaka and A. S. Maest (eds.), Water-Rock Interaction. Balkema, Rotterdam, pp. 13-21. 

This book will be of great interest to graduate students and academic researchers in the helds of geochemistry, environmental engineering, contaminant hydrology, geomicrobiology, and numerical modeling. 

I expand treatment of sorption, ion exchange, and surface complexation, in terms of the various descriptions in use today in environmental chemistry. And I integrate all the above with the principals of mass transport, to produce reactive transport models of the geochemistry and biogeochemistry of the Earth s shallow crust. As in the first edition, I try to juxtapose derivation of modeling principles with fully worked examples that illustrate how the principles can be applied in practice. 

R. T. Cygan and J. D. Kubicki (eds.), Molecular Modelling Theory in the Geosciences. Reviews in Mineralogy and Geochemistry, vol. 42, Geochemical Society, Mineralogical... 

Laidlaw, M.A.S., Mielke, H.W., Filippelli, G.M., Johnson, D.L., Gonzales, C.R., 2005. Seasonality and children s blood lead levels developing a predictive model using climatic variables and blood lead data from Indianapolis, Indiana, Syracuse, New York, and New Orleans, Louisiana (USA). Environmental Health Perspectives, 113, 793-800. Mielke, H.W., Gonzales C., Powell E., Mielke PW, Jr. 2008. Urban soil lead (Pb) footprint Comparison of public and private housing of New Orleans. Environmental Geochemistry and Health, 30, 231-242. 

Nordstrom, D.K. 2004. Modeling low-temperature geochemical processes. In Drever, J.l. (ed.) Surface and Ground Water, Weathering, and Soils 5, Holland, H.D. Turekian, K.K. (ed.) Treatise on Geochemistry, Elsevier, 37-72. 

Keywords arsenic, mobility, attenuation, geochemistry, hydrologic modelling... 

Schwertmannite and the chemical modeling of iron in acid sulfate waters. Geochimica et Cosmochimica Acta, 60, 2111-2121. Jonsson, J. Persson, P., Sjoberg, S., Lovgren, L. 2005. Schwertmannite precipitated from acid mine drainage phase transformation, sulphate release and surface properties. Applied Geochemistry, 20, 179-191. 

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