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Composition of fluids in quartz: discrimination of magma pulses in a Caledonian granitoid

Published online by Cambridge University Press:  05 July 2018

R. A. Batchelor ,
D. C. Armstrong  and
M. McDonald
R. A. Batchelor
Affiliation:
Department of Geography and Geology, University of St. Andrews, Fife, Scotland
D. C. Armstrong
Affiliation:
British Antarctic Survey, High Cross, Madingley Road, Cambridge
M. McDonald
Affiliation:
Department of Geography and Geology, University of St. Andrews, Fife, Scotland
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Abstract

Fluids trapped inside fluid inclusions in quartz from the multiphase Starav monzogranite in Etive, Argyll, were extracted under vacuum and quantitative data for H2O and CO2 were obtained manometrically. Na and K were determined on an aqueous leach from the decrepitated grains. A bivariate diagram of H2O/CO2 versus Na/K discriminates between magma pulses and mirrors the whole-rock trace-element chemistry. This work shows that compositional variations of fluids in quartz from a weakly mineralised granitoid intrusion are sensitive indicators of its magmatic history and identify subtle changes in its mineralogical composition.

Keywords

fluid compositionquartzmagma pulsesCaledonian granitoid
Type
The Hallimond Lecture
Information
Mineralogical Magazine , Volume 56 , Issue 384 , September 1992 , pp. 335 - 342
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1992

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