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"Thermodynamics of a magmatic gas phase" 50 years later; discussion

John Verhoogen and J. Nicholls
"Thermodynamics of a magmatic gas phase" 50 years later; discussion
The Canadian Mineralogist (December 2000) 38, Part 6: 1313-1328


In a paper published in 1949, Verhoogen examined many aspects of the behaviour of a magmatic gas phase and discussed two other possible processes in magmas: distillation and crystallization of indifferent states. Distillation occurs when a constituent has a higher concentration in the vapour than in the melt. The volatile constituents of magmas (H (sub 2) O, CO (sub 2) , H (sub 2) S) obviously fit the definition of constituents that undergo distillation; however, Verhoogen did not discuss the reverse process, partitioning of a constituent into the melt phase rather than the gas phase. HF is a constituent that undergoes reverse distillation; its concentration is higher in a melt than in a gas phase. Volatile constituents that undergo reverse distillation cause magmas to vesiculate at shallower depths than those that undergo distillation. Indifferent states occur during processes that change the masses of the phases of a system but leave their compositions unchanged; univarient systems and azeotropes are familiar examples of indifferent states. Thermodyanic databases constructed in the last decade provide the tools to explore the processes described by Verhoogen 50 years ago.

ISSN: 0008-4476
EISSN: 1499-1276
Coden: CAMIA6
Serial Title: The Canadian Mineralogist
Serial Volume: 38, Part 6
Title: "Thermodynamics of a magmatic gas phase" 50 years later; discussion
Affiliation: University of Calgary, Department of Geology and Geophysics, Calgary, AB, Canada
Pages: 1313-1328
Published: 200012
Text Language: English
Summary Language: French
Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada
References: 31
Accession Number: 2001-066978
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendices; for reference to original see Verhoogen, J. Thermodynamics of a magmatic gas phase, Univ. Calif., Publ. Geol. Sci. 28, p .91-135, 1949
Illustration Description: illus. incl. 1 table
N42°00'00" - N49°00'00", W117°15'00" - W111°04'60"
N20°10'00" - N20°10'00", W155°19'60" - W155°19'60"
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 200121
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