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Feldspar crystallisation in felsic magmas; a review

Hanna Nekvasil
Feldspar crystallisation in felsic magmas; a review (in The second Hutton symposium on the origin of granites and related rocks; proceedings, P. E. Brown (editor) and B. W. Chappell (editor))
Special Paper - Geological Society of America (1992) 272: 399-407

Abstract

Feldspar compositional paths are influenced only to a minor degree by P. The presence of H (sub 2) O, or other melt components incompatible in feldspar, has a more major effect, not only increasing the T interval over which feldspar crystallizes, but also decreasing the amount of Ab enrichment of the feldspar which occurs during crystallization. The amount and behaviour of H (sub 2) O in the magma has a pronounced influence on feldspar compositions when two feldspars are stable. Under conditions of high bulk H (sub 2) O content or constant activity of H (sub 2) O, plagioclase and alkali feldspar compositions evolve by increasing Ab content similar to the behaviour shown by the simple binary systems. If the bulk H (sub 2) O content is low, however, and the H (sub 2) O content increases during crystallization, plagioclase evolves by increasing Ab content until alkali feldspar is stabilized. From that point on, plagioclase compositions change mainly by decreasing Or content, where alkali feldspar evolves mainly by increasing Or content.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 272
Title: Feldspar crystallisation in felsic magmas; a review
Title: The second Hutton symposium on the origin of granites and related rocks; proceedings
Author(s): Nekvasil, Hanna
Author(s): Brown, P. E.editor
Author(s): Chappell, B. W.editor
Affiliation: State University of New York at Stony Brook, Department of Earth and Space Sciences, Stony Brook, NY, United States
Affiliation: University of St. Andrews, Department of Geology, St. Andrews, United Kingdom
Pages: 399-407
Published: 1992
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2272-1
Meeting name: The second Hutton symposium on the Origin of granites and related rocks
Meeting location: Canberra, AUS, Australia
Meeting date: 19910923Sept. 23-28, 1991
References: 31
Accession Number: 1993-010090
Categories: Igneous and metamorphic petrology
Document Type: Serial Conference document
Bibliographic Level: Analytic
Annotation: Originally publ. in Transact. R. Soc. Edinburgh, Earth Sci., Vol. 83, parts 1 and 2
Illustration Description: illus.
Secondary Affiliation: Australian National University, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 1993
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