The reaction muscovite + quartz andalusite + K-feldspar + water; Part 1, Growth kinetics and mechanism

Schramke, Janet A.; Kerrick, D. M.; Lasaga, Antonio C.

doi:10.2475/ajs.287.6.517

Cited by 76 publications

(72 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, a number of experiments near equilibrium have shown that the actual relationship between r j and DG r deviates from this so-called linear kinetics (Schramke et al, 1987;Nagy et al, 1991;Nagy andLasaga, 1992, 1993;Burch et al, 1993;Gautier et al, 1994;Alekseyev et al, 1997;Cama et al, 2000;Taylor et al, 2000;Beig and Lü ttge, 2006;Hellmann and Tisserand, 2006). As shown below, the linear TST rate law also cannot fit the experimental data of Zhu and Lu (2009).…”

mentioning

confidence: 84%

Coupled alkali feldspar dissolution and secondary mineral precipitation in batch systems: 4. Numerical modeling of kinetic reaction paths

Zhu

Lü

Zheng

et al. 2010

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

This paper explores how dissolution and precipitation reactions are coupled in batch reactor experimental systems at elevated temperatures. This is the fourth paper in our series of "Coupled Alkali Feldspar Dissolution and Secondary Mineral Precipitation in Batch Systems". In our third paper, we demonstrated via speciation-solubility modeling that partial equilibrium between secondary minerals and aqueous solutions was not attained in feldspar hydrolysis batch reactors at 90-300°C and that a strong coupling between dissolution and precipitation reactions follows as a consequence of the slower precipitation of secondary minerals ). Here, we develop this concept further by using numerical reaction path models to elucidate how the dissolution and precipitation reactions are coupled. Modeling results show that a quasi-steady state was reached. At the quasi-steady state, dissolution reactions proceeded at rates that are orders of magnitude slower than the rates measured at far from equilibrium. The quasi-steady state is determined by the relative rate constants, and strongly influenced by the function of Gibbs free energy of reaction (DG r ) in the rate laws.To explore the potential effects of fluid flow rates on the coupling of reactions, we extrapolate a batch system (Ganor et al., 2007) to open systems and simulated one-dimensional reactive mass transport for oligoclase dissolution and kaolinite precipitation in homogeneous porous media. Different steady states were achieved at different locations along the one-dimensional domain. The time-space distribution and saturation indices (SI) at the steady states were a function of flow rates for a given kinetic model. Regardless of the differences in SI, the ratio between oligoclase dissolution rates and kaolinite precipitation rates remained 1.626, as in the batch system case (Ganor et al., 2007). Therefore, our simulation results demonstrated coupling among dissolution, precipitation, and flow rates.Results reported in this communication lend support to our hypothesis that slow secondary mineral precipitation explains part of the well-known apparent discrepancy between lab measured and field estimated feldspar dissolution rates (Zhu et al., 2004). Here we show how the slow secondary mineral precipitation provides a regulator to explain why the systems are held close to equilibrium and show how the most often-quoted "near equilibrium" explanation for an apparent field-lab discrepancy can work quantitatively. The substantiated hypothesis now offers the promise of reconciling part of the apparent fieldlab discrepancy.

show abstract

mentioning

confidence: 84%

Coupled alkali feldspar dissolution and secondary mineral precipitation in batch systems: 4. Numerical modeling of kinetic reaction paths

Zhu

Lü

Zheng

et al. 2010

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…The kinetics of this reaction have been studied recently by Schramke et al (1986a). Several important results from that work which shed light on the previous discussion of metamorphic fluid-mineral reactions will be summarized here.…”

Section: Kinetics Of Metamorphic Fluid-rock Reactionsmentioning

confidence: 99%

“…However, some recent experimental data (e.g. Tanner et al, 1985;Schramke et al, 1986a) can begin to provide the type of answers that are needed.…”

Section: Kinetics Of Metamorphic Fluid-rock Reactionsmentioning

confidence: 99%

“…The latter are of central importance because they represent boundaries separating the presence or absence of one or more minerals and therefore are the traditional mappable isograds. Recent papers (Matthews, 1980;Walther and Orville, 1982; Ferry, 1983a, b;Wood and Walther, 1983; Walther and Wood, 1984; RuNe and Thompson, 1985;Tanner et al, 1985;Schramke et al, 1986a) have begun to address the kinetic descriptions of these reactions. We want to extend these treatments in this paper.…”

Section: ~) Copyright the Mineralogical Societymentioning

confidence: 99%

“…The extension of the data to field conditions and the possibility of surface control in nature will be further quantified below. We should stress that in metamorphic reactions controlled by surface processes it is usually one mineral surface that is important, as obtained by Schramke et al (1986a). Which mineral surface controls the kinetics must be determined experimentally and, of course, may vary if the relative abundances of the reactants or products change sufficiently.…”

Section: Kinetics Of Metamorphic Fluid-rock Reactionsmentioning

confidence: 99%

See 2 more Smart Citations

Metamorphic reaction rate laws and development of isograds

Lasaga

1986

Mineral. mag.

113

View full text Add to dashboard Cite

A n S T R A C T. New data on the kinetics of dehydration o f muscovite+quartz suggest the necessity for a careful treatment of both surface kinetics and diffusion processes in metamorphic reactions. A new model is proposed that illustrates the relative role of diffusion and surface reactions in the overall metamorphic process. The rate law for the reaction at mineral surfaces derived from the experimental data is shown to be probably non-linear and similar to rate laws derived from Monte Carlo calculations. The experimental rate data is then used in a heat flow calculation to model the evolution of the muscovite isograd in the field. The position of the isograd, the temperature oversteps above equilibrium, and the width of 'reaction zones' are then analysed as a function of intrusion size and kinetic parameters.KEYWORDS: metamorphic reactions, surface kinetics, diffusion, rate laws. THE fOCUS of metamorphic petrology today is shifting from a static mode based on the thermodynamics of mineral assemblages to a dynamic mode aimed at the quantification of the processes that produced the metamorphism. As a result, the non-equilibrium aspects and the kinetics of metamorphic processes are being increasingly studied. The proper role of equilibrium versus kinetics in describing metamorphism is still being debated today. As petrologists initially tackled the complexities of the texture and mineralogy of metamorphic rocks, many of which could not coexist according to an equilibrium model, the concept of local equilibrium (Thompson, 1959;Helgeson, 1968; Fisher and Elliott, 1974) was born. In this fashion, equilibrium was maintained at least on a local scale, which meant essentially for surfaces of mineral grains in physical contact with each other. Isotope studies (Lattanzi et al., 1980; Rumble et al., 1982;Rumble and Spear, 1983;Tracy et al., 1983) have investigated the length scale of equilibrium and found many cases where it was only a few centimetres.Closer inspection of the chemical composition of minerals has unearthed a wide variety of zoning profiles which preserve, albeit encoded by the ~) Copyright the Mineralogical Societykinetics, the details of the metamorphic history. The ubiquitous zoning found in several metamorphic minerals has led to recent papers on their kinetic significance (Lasaga et al., 1977;Lasaga, 1983;Ozawa, 1984;Smith and Ehrenberg, 1984;Wilson andSmith and Wilson, 1985; Docka et al. (in press).More recently, the kinetic study has been extended to the generation, motion and characterization of metamorphic fluids. Within the assumption of local equilibrium, it was logical to assume that the local mineral assemblage would control or buffer the composition of the fluid phase during dehydration/hydration and decarbonation/ carbonation reactions and that the kinetics were fast enough to be ignored. This control, however, can only be achieved by the continuous and concurrent dissolution and growth of one or several minerals. As Greenwood (1975) has shown, the amount of fluid involved during evolution...

show abstract

Chemomechanical evolution of pore space in carbonate microstructures upon dissolution: Linking pore geometry to bulk elasticity

Arson

Vanorio

2015

JGR Solid Earth

View full text Add to dashboard Cite

One of the challenges faced today in a variety of geophysical applications is the need to understand the changes of elastic properties due to time‐variant chemomechanical processes. The objective of this work is to model carbonate rock elastic properties as functions of pore geometry changes that occur when the solid matrix is dissolved by carbon dioxide. We compared two carbonate microstructures: porous micrite (“mudstone”) and grain‐supported carbonate (“packstone”). We formulated a mathematical model that distinguishes the effects of microporosity and macroporosity on stiffness changes. We used measures of mechanical and chemical porosity changes recorded during injection tests to compute elastic moduli and compare them to moduli obtained from wave velocity measurements. In mudstones, both experimental and numerical results indicate that bulk moduli change by less than 5%. The evolution of elastic moduli is controlled by macropore enlargement. In packstones, model predictions underestimate changes of elastic moduli with total porosity by 10% to 80%. The total porosity variation is 60% to 75% smaller than the chemical porosity variation, which indicates that pore expansion due to dissolution is counterbalanced by pore shrinkage due to compaction. Packstone elastic properties are controlled by grain sliding. The methodology presented in this paper can be generalized to other chemomechanical processes studied in rocks, such as dislocations, glide, diffusive mass transfer, recrystallization, and precipitation.

show abstract

The reaction muscovite + quartz andalusite + K-feldspar + water; Part 1, Growth kinetics and mechanism

Cited by 76 publications

References 0 publications

Coupled alkali feldspar dissolution and secondary mineral precipitation in batch systems: 4. Numerical modeling of kinetic reaction paths

Coupled alkali feldspar dissolution and secondary mineral precipitation in batch systems: 4. Numerical modeling of kinetic reaction paths

Metamorphic reaction rate laws and development of isograds

Chemomechanical evolution of pore space in carbonate microstructures upon dissolution: Linking pore geometry to bulk elasticity

Contact Info

Product

Resources

About