Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-08T16:29:34.122Z Has data issue: false hasContentIssue false

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
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

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.

Type
The Hallimond Lecture
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barritt, S.D. (1983) The controls of radioelement distribution in the Etive and Cairngorm granites: implications for heat production. Open University, Ph.D. thesis (unpubl.)Google Scholar
Batchelor, R.A. (1987) Geochemical and petrological characteristics of the Etive granitoid complex, Argyll. Scott. J. Geol, 23, 227–9.CrossRefGoogle Scholar
Behar, F. and Pineau, F. (1979) Analyse de CO2, H2O, hydrocarbures des inclusions fluides par chromato-graphie en phase gazeuze: application aux fentes alpines et aux roches metamorphiques. Bull. Mineral, 102, 611–21.Google Scholar
Borisenko, A.S. (1977) Study of the salt composition of solutions in gas-liquid inclusions in minerals by the cryometric method. Soviet Geology and Geographies, 18, 1119.Google Scholar
Bottrell, S.H. and Yardley, B.W.D. (1988) The composition of a primary granite-derived ore fluid from SW England determined by fluid inclusion analysis. Geochim. Cosmochim. Acta, 52, 585–8.CrossRefGoogle Scholar
Bottrell, S.H. and Yardley, B.W.D. Shepherd, T.J., Yardley, B.W.D., and Dubessy, J. (1988) A fluid inclusion model for the genesis of the ores of the Dolgellau Gold Belt, North Wales. J. GeoL Soc. Lond., 145, 139–45.CrossRefGoogle Scholar
Burruss, R.C. (1981a) Analysis of phase equilibria in C—O-H—S fluid inclusions. In Short Course in Fluid Inclusions: Applications to Petrology. (L. S. Hollister and M. L. Crawford, eds.), Min. Assoc. Can. Short Course Handbook, 6, 3974.Google Scholar
Burruss, R.C. (1981b) Analysis of fluid inclusions: phase equilibria at constant volume. Amer. J. Sci., 281, 1104–26.CrossRefGoogle Scholar
Collins, P.L.F. (1979) Gas hydrates in CO2-bearing fluid inclusions and the use of freezing data for estimation of salinity. Econ. Geol., 74, 1435–44.CrossRefGoogle Scholar
Crawford, M.L. (1981) Phase equilibria in aqueous fluid inclusions. In: Short Course in Fluid Inclusions: Applications to Petrology (L. S. Hollister and M. L. Crawford, eds.), Min. Assoc. Can. Short Course Handbook, 6, 75100.Google Scholar
Hansteen, T.H. and Lustenhouwer, W.J. (1990) Silicate melt inclusions from a mildly peralkaline granite in the Oslo paleorift, Norway. Mineral. Mag., 54, 195205.CrossRefGoogle Scholar
Haslam, H.W. and Cameron, D.G. (1985) Dissemi-nated molybdenum mineralisation in the Etive plutonic complex in the western Highlands of Scotland. Mineral. Reconn. Prog. Rep. B.G.S., No. 76.Google Scholar
Roedder, E. (1958) Technique for the extraction and partial chemical analysis of fluid-filled inclusions from minerals. Econ. Geol., 53, 235–19.CrossRefGoogle Scholar
Roedder, E. (1972) Compositions of fluid inclusions. U.S. Geol.Surv. Prof. Paper, 440-J.CrossRefGoogle Scholar
Shepherd, T.J. (1981) Temperature-programmable heating-freezing stage for microthermometric analy-sis of fluid inclusions. Econ. Geol., 76, 1244–7.CrossRefGoogle Scholar
Shepherd, T.J. and Waters, P. (1984) Fluid inclusion gas studies, Carrock Fell Tungsten Deposit, England: Impli-cations for regional exploration. Mineral.Deposita, 19, 304–14.CrossRefGoogle Scholar
Shepherd, T.J. Rankin, A.H., and Alderton, D.H.M. (1985) A Practical Guide to Fluid Inclusion Studies. Blackie, Glasgow.Google Scholar
Sorby, H.C. (1858) On the microscopic structure of crystals, indicating the origin of minerals and rocks. Quart. J. Geol. Soc., 14, 453500.CrossRefGoogle Scholar
Thornton, C.P. and Tuttle, O.F. (1960) Chemistry of igneous rocks. 1. Differentiation Index. Amer. J. Sci., 258, 664–84.CrossRefGoogle Scholar
Wilkinson, J.J. (1990) The role of metamorphic fluids in the development of the Cornubian orefield: fluid inclusion evidence from south Cornwall. Mineral. Mag., 54, 219–30.CrossRefGoogle Scholar