Hostname: page-component-76fb5796d-r6qrq Total loading time: 0 Render date: 2024-04-26T10:50:05.768Z Has data issue: false hasContentIssue false
  • English
  • Français

Thermodynamic models of reactions involving garnet in a sillimanite/staurolite schist

Published online by Cambridge University Press:  05 July 2018

C. T. Foster Jr.
C. T. Foster Jr.*
Affiliation:
Department of Geology, University of Iowa, Iowa City, Iowa 52242, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Textures produced by reactions involving garnet in a sillimanite-staurolite schist have been investigated using an irreversible thermodynamic model. The model predicts that the local production or consumption of garnet is strongly influenced by the proximity of garnet to growing sillimanite and dissolving staurolite. Garnets within sillimanite segregations should dissolve near the sillimanite-bearing centre of the segregation while garnets within or adjacent to staurolite poikilo-blasts should grow as the staurolite is replaced by a muscovite-rich pseudomorph. Garnets located in the matrix may grow, not react at all, or dissolve depending on the local configuration of nearby sillimanite, staurolite, and garnet. Textures predicted by the model are similar to those observed in thin section: many garnets are truncated within sillimanite segregations; garnets located in pseudo-morphs after staurolite are equant and have thick unpoikilitic rims that suggest growth; most matrix garnets also have thick inclusion-free rims that suggest growth but a few have thin rims, indicating little growth, or are irregularly shaped, suggesting dissolution.

Keywords

garnet texturesgarnet-sillimanite-staurolite schistirreversible thermodynamic models
Type
Rates of Metamorphic Reactions
Information
Mineralogical Magazine , Volume 50 , Issue 357 , September 1986 , pp. 427 - 439
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1986

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

Bailes, A.H., and McRitchie, W.D. (1978) The transition from low to high grade metamorphism in the Kisseynew Sedimentary Gneiss Belt, Manitoba, Geol. Surv. Can. Paper 78-10,155-78.Google Scholar
Carmichael, D.M. (1969) On the mechanism of prograde metamorphic reactions in quartz-bearing pelitic rocks. Contrib. Mineral. Petrol. 20, 244-67.CrossRefGoogle Scholar
Fisher, G.W. (1975) The thermodynamics of diffusioncontrolled metamorphic processes. In Mass Transport Phenomena in Ceramic.(A. R. Cooper and A. H. Heuer, eds.), 111-22. Plenum, New York.Google Scholar
Fisher, G.W. (1977) Nonequilibrium thermodynamics in metamorphism. In Thermodynamics in Geolog.(D. G. Fraser, ed.), 381-403. Riedel, Boston.Google Scholar
Fisher, G.W. (1978) Rate laws in metamorphism. Geochim. Cosmochim. Ada. 42, 1035-50.CrossRefGoogle Scholar
Foster, C.T., Jr. (1975) Diffusion Controlled Growth of Metamorphic Segregations in Sillimanite Grade Pelitic Rocks near Rangeley, Maine U.S.A.Ph.D. thesis, the Johns Hopkins University, Baltimore, Md.Google Scholar
Foster, C.T., Jr. (1977) Mass transfer in sillimanite-bearing pelitic schists near Rangeley, Mains. Am. Mineral. 62, 727. 46.Google Scholar
Foster, C.T., Jr. (1981) A thermodynamic model of mineral segregations in the lower sillimanite zone near Rangeley, Maine. Ibid. 66, 260-77.Google Scholar
Foster, C.T., Jr. (1982) Textural variation of sillimanite segregations. Can. Mineral. 20, 379-92.Google Scholar
Foster, C.T., Jr. (1983) Thermodynamic models of biotite pseudomorphs after staurolite. Am. Mineral. 68, 389-97.Google Scholar
Guidotti, C.V. (1968) Prograde muscovite pseudomorphs after staurolite in the Rangeley-Oquossoc area, Maine. Ibid. 53, 1368-76.Google Scholar
Guidotti, C.V. (1970) The mineralogy and petrology of the transition from the lower to upper sillimanite zone in the Oquossoc area, Maine. J. Petrol. 11, 277-336.CrossRefGoogle Scholar
Guidotti, C.V. (1974) Transition from staurolite to sillimanite zone, Rangeley Quadrangle, Maine. Geol. Soc. Am. Bull. 85, 475-90.2.0.CO;2>CrossRefGoogle Scholar
Joesten, R. (1974) Local equilibrium and metasomatic growth of zoned calc-silicate nodules from a contact aureole, Christmas Mountains, Big Bend Regions, Texas. Am. J. Sci. 274, 876-901.CrossRefGoogle Scholar
Joesten, R. (1977) Evolution of mineral assemblage zoning in diffusion metasomatism. Geochim. Cosmochim. Ad. 41, 649-70.CrossRefGoogle Scholar
Nishiyama, T. (1983) Steady diffusion model for olivineplagioclase corona growth. Ibid. 47, 283-94.Google Scholar
Ridley, J. (1985) The effect of reaction enthalpy on the progress of a metamorphic reaction. In Metamorphic Reactions: Kinetics, Textures and Deformatio.(A. B. Thompson and D. C. Rubie, eds.), 80-97. Springer- Verlag, New York.Google Scholar
Rubie, D.C. (1983) Reaction-enhanced ductility: the role of solid-solid univariant reactions in deformation of the crust and mantle. Tectonophys. 96, 331. 52.CrossRefGoogle Scholar
Walther, J.V., and Wood, B.J. (1984) Rate and mechanism in prograde metamorphism. Contrib. Mineral. Petrol. 88, 246-59.CrossRefGoogle Scholar
Yardley, B.W.D. (1977) The nature and significance of the mechanism of sillimanite growth in the Connemara schists, Ireland. Ibid. 65, 53-8.CrossRefGoogle Scholar