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GEOREF RECORD

Structure and rheology of iron-bearing Na (sub 2) O-Al (sub 2) O (sub 3) -SiO (sub 2) melts

Sharon Webb
Structure and rheology of iron-bearing Na (sub 2) O-Al (sub 2) O (sub 3) -SiO (sub 2) melts (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): 223-232

Abstract

The viscosity of a series of Na (sub 2) O-FeO-Fe (sub 2) O (sub 3) -Al (sub 2) O (sub 3) -SiO (sub 2) melts has been measured by micropenetration methods. The viscosity of the Fe-bearing melts follows the same compositional trend as the Fe-free Na (sub 2) O-Al (sub 2) O (sub 3) -SiO (sub 2) melts as a function of Na/Al at constant SiO (sub 2) content: viscosity increases with decreasing peralkalinity and remains almost constant for all compositions in the peraluminous field. The addition of 1 mol % Fe (sub 2) O (sub 3) to the Fe-free peraluminous composition causes approximately 1 log (sub 10) Pa s decrease in viscosity, whereas approximately 3 mol % Fe (sub 2) O (sub 3 ) needs to be added to the peralkaline compositions to produce a similar decrease in viscosity. The need for more charge-balancing cations in the peraluminous melt structure appears to control the Fe (super 2+) /Fe (super total) , with the peraluminous compositions having a large Fe (super 2+) /Fe (super total) (0.6) compared with that for the peralkaline compositions (0.3). Although tri-clusters probably exist in peraluminous melts, the configurational entropy term at a viscosity of 10 (super 12) Pa s calculated for these melts suggests that the flow process is not initiated at a tri-cluster site. Thus the peralkaline amd peraluminous melts not only have different structures but also have slightly different flow processes. These differences are reflected in the viscosity and activation energy for viscous flow.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 17
Serial Issue: 2
Title: Structure and rheology of iron-bearing Na (sub 2) O-Al (sub 2) O (sub 3) -SiO (sub 2) melts
Title: EMPG X; Experimental mineralogy, petrology and geochemistry
Author(s): Webb, Sharon
Author(s): Woodland, A. B.editor
Author(s): Foley, S. F.editor
Affiliation: Goettingen University, Mineralogy Department, Gottingen, Federal Republic of Germany
Pages: 223-232
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: 38
Accession Number: 2005-041696
Categories: General mineralogy
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200525
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