Quartz dissolution

Fig. 27.2. Concentration of dissolved silica and the quartz dissolution rate along a quartz sand aquifer being recharged at left by rainwater, for the scenario considered in Figure 27.1. Results were calculated assuming a range of flow velocities rapid flow corresponds to a Damkohler number Da less than one, whereas Da is greater than one for slow flow.

We set quartz dissolution and precipitation according to a kinetic rate law (Knauss and Wolery, 1988 see Chapter 16),... 

Bennett, P. C. (1991), "Quartz Dissolution in Organic-Rich Aqueous Systems", Geochim. Cosmochim. Acta 55, 1781-1797. 

Brady, P. V., and J. V. Walther (1991), "Kinetics of Quartz Dissolution at Low Temperatures", Chem. Geoi., in press. 

Bolton EW, Lasaga AC, Rye DM (1996) A model for the kinetic control of quartz dissolution and precipitation in porous media flow with spatially variable permeability Eormulation and examples of thermal convection. J Geophys Res 101 22,157-22,187 Bolton EW, Lasaga AC, Rye DM (1997) Dissolution and precipitation via forced-flux injection in the porous medium with spatially variable permeability Kinetic control in two dimensions. J Geophys Res 102 12,159-12,172... 

Convective dissolution rate for quartz in an andesitic melt may be calculated similarly, but the error may be larger than the normal 20% relative because quartz dissolution increases Si02 content so much, leading to orders of magnitude increase in viscosity for the interface melt (viscosity is about 120 Pa s for the initial andesitic melt and 1.7 x lO" Pa s for the interface rhyolitic melt). Because... 

Mechanisms and rates of quartz dissolution in melts in the CMAS (CaO-... 

Henderson, J. H., Syers, J. K. and Jackson, M. L, Quartz dissolution as influenced by pH and the presence of a disturbed surface layer, Israel... 

The most comprehensive dataset for a silicate has been compiled for quartz dissolution over a range of temperature and pressure (e.g., Rimstidt and Barnes, 1980 Knauss and Wolery, 1988 Wollast and Chou, 1988 Brady and Walther, 1990 Dove and Crerar, 1990 Hiemstra and van Riemsdijk, 1990 Dove and Elston, 1992 Dove and Rimstidt, 1994 Tester et al., 1994 Dove, 1995). Dove (1994, 1995) has modelled the rate of dissolution of quartz as a function of temperature by the rate equation,... 

Dove P. M. and Crerar D. A. (1990) Kinetics of quartz dissolution in electrolyte solutions using a hydrothermal mixed flow reactor. Geochim. Cosmochim. Acta 54, 955-969. 

Gautier J.-M., Oelkers E. H., and Schott J. (2001) Are quartz dissolution rates proportional to BET surface areas Geochim. Cosmochim. Acta 65(7), 1059-1070. 

Gratz A. J. and Bird P. (1993) Quartz dissolution negative crystal experiments and a rate law. Geochim. Cosmochim. Acta 57, 965-976. 

Poulson S. R., Drever J. I., and Stillings L. L. (1997) Aqueous Si-oxalate complexing, oxalate adsorption onto quartz, and the effect of oxalate upon quartz dissolution rates. Chem. Geol. 140(1-2), 1-7. 

The calculation of mineral weathering rates based on solute concentrations is complicated by the fact that individual solute species are commonly produced by more than one weathering reaction. In granite weathering, for example, aqueous silicon is produced not only from plagio-clase weathering (Equation (2)), but also by K-feldspar, biotite, hornblende and quartz dissolution. In addition, secondary minerals such as kaolinite take up aqueous silicon (Equation (2)). 

Schulz M. S. and White A. F. (1999) Chemical weathering in a tropical watershed, Luquillo mountains, Puerto Rico III. Quartz dissolution rates. Geochim. Cosmochim. Acta 63, 337-350. 

Cathelineau M. (1987) U-Th-REE mobility during albitization and quartz dissolution in granitoids evidence from south-east French Massif Central. Bull. Mineral. 110, 249-259. 

Evans J. (1990) Quartz dissolution during shale diagenesis implications for quartz cementation in sandstones. Chem. Geol. 84, 239-240. 

Bennett, P.C. Siegel, D.I. (1989) Silica organic complexes and enhanced quartz dissolution in water by organic acids. In Miles, D.L. (Ed.) Proceedings, 6th International Symposium on Water-Rock Interaction, Rotterdam Balkema, pp. 69-72. 

Another useful concept is that of congruent and incongruent reactions. These terms describe reactions involving the dissolution of minerals. If all the products of a dissolution reaction are soluble, the reaction is called congruent, as in the case of the quartz dissolution reaction (1.6) described above. Because, as written, the olivine weathering reaction leads to quartz precipitation it is an incongruent reaction. 

H4Si04 <- + HsSiO (quartz dissolution) [H+HHsSiOi] [H4Si04] HjSiOi 1.6939E-10... 

Dove P., and D. A. Crerar (in press), Kinetics of Quartz Dissolution in Electrolyte Solutions Using a Hydrothermal Mixed Flow Reactor, Geochim. Cosmochim. Acta. 

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