Skip to Main Content
GEOREF RECORD

Thermodynamic modeling of solubility and speciation of silica in H (sub 2) O-SiO (sub 2) fluid up to 1300 degrees C and 20 kbar based on the chain reaction formalism

Taras V. Gerya, Walter V. Maresch, Michael Burchard, Vitali Zakhartchouk, Nikos L. Doltsinis and Thomas Fockenberg
Thermodynamic modeling of solubility and speciation of silica in H (sub 2) O-SiO (sub 2) fluid up to 1300 degrees C and 20 kbar based on the chain reaction formalism (in EMPG X; Experimental mineralogy, petrology and geochemistry, A. B. Woodland (editor) and S. F. Foley (editor))
European Journal of Mineralogy (April 2005) 17 (2): 269-283

Abstract

A thermodynamic formalism is proposed for modelling both absolute silica solubility and speciation of dissolved silica using a combination of the chain reaction approach and a new Gibbs free energy equation of water based on a homogeneous reaction formalism. For a given SiO (sub 2) buffer (e.g. quartz) and the coexistent H (sub 2) O-SiO (sub 2) fluid, both solubility and speciation of silica can be described by the two reactions: monomer-forming standard reaction SiO (sub 2(s)) + 2(H (sub 2) O)L = (SiO (sub 2) ). (H (sub 2) O) (sub 2) and polymer-forming chain reaction (SiO (sub 2) ) (sub n-1) . (H (sub 2) O) (sub n) + (SiO (sub 2) ). (H (sub 2) O) (sub 2) = (SiO (sub 2) ) (sub n) . (H (sub 2) O) (sub n+1) + (H (sub 2) O) (sub L) where 2 < or = n < or = infinity and (H (sub 2) O) (sub L) = 'liquid-like' water molecules in the aqueous fluid. Discrepancies between directly determined solubility data and data obtained from in situ Raman spectra are ascribed to possible exerimental problems of equilibration and to inherent difficulties of interpreting Raman spectra of dilute H (sub 2) O-SiO (sub 2) solutions. The model indicates that dissolved silica in quartz-buffered aqueous solutions is considerably polymerized , exceeding 20-25 % at all temperatures above 400 degrees C.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 17
Serial Issue: 2
Title: Thermodynamic modeling of solubility and speciation of silica in H (sub 2) O-SiO (sub 2) fluid up to 1300 degrees C and 20 kbar based on the chain reaction formalism
Title: EMPG X; Experimental mineralogy, petrology and geochemistry
Author(s): Gerya, Taras V.Maresch, Walter V.Burchard, MichaelZakhartchouk, VitaliDoltsinis, Nikos L.Fockenberg, Thomas
Author(s): Woodland, A. B.editor
Author(s): Foley, S. F.editor
Affiliation: ETH-Zuerich, Geologisches Institut, Zurich, Switzerland
Pages: 269-283
Published: 200504
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
Meeting name: 10th international symposium on Experimental mineralogy, petrology and geochemistry
Meeting location: Frankfurt, DEU, Federal Republic of Germany
Meeting date: 20040404April 4-7, 2004
References: 46
Accession Number: 2005-041701
Categories: General geochemistry
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Secondary Affiliation: Russian Academy of Sciences, RUS, Russian FederationRuhr-Universitaet Bochum, DEU, Federal Republic of Germany
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200525
Close Modal

or Create an Account

Close Modal
Close Modal