Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-27T10:37:57.620Z Has data issue: false hasContentIssue false

Pyrometamorphic breakdown of cordierite - muscovite intergrowths

Published online by Cambridge University Press:  05 July 2018

R. H. Grapes*
Affiliation:
Institut für Mineralogie, Petrologie und Geochemie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany
*

Abstract

Backscattered electron imaging of cordierite-muscovite intergrowths near the margin of a schist xenolith in trachytic tephra of the Wehr Volcano, East Eifel area, Germany, show that they have undergone disequilibrium melting to form spinel + biotite + sillimanite/?mullite + peraluminous melt. Textures indicate that in the initial stage of reaction, spinel, biotite and sillimanite/?mullite formed with melt produced in cordierite and spinel + ?mullite with melt after muscovite, providing evidence of two different reaction pathways. Fe-Mg distributions between biotite/spinel, cordierite/spinel, cordierite/ biotite suggest a melting temperature of ∼770°C, implying overstepping of various calculated and experimentally determined mineral breakdown curves of between 30 and 170°C during short-term heating before the xenolith was quenched on eruption.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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

Blümel, P. and Schreyer, W. (1976 Progressive regional low-pressure metamorphism in Moldanubian metapelites of the northern Bavarian forest, Germany. Krystalinikum, 12, 730.Google Scholar
Blümel, P. and Schreyer, W. (1977 Phase relations in pelitic and psammitic gneisses of the sillimanitepotash feldspar and cordierite – potash feldspar zones in the Moldanubicum of the Lam-Bodenmais area, Bavaria. Journal of Petrology, 18, 431459.CrossRefGoogle Scholar
Brauns, S. (1911 Die kristallinen Schiefer des Laacher Seegebiets und ihre Unbidung zu Sanidinit . E. Schweizerbath’sche Ver lagsbuchhandlung, Stuttgart, 1911, 61 pp.Google Scholar
Brearley, A.J. (1986 An electron optical study of muscovite breakdown in pelitic xenoliths during pyrometamorphism. Mineralogical Magazine, 50, 385397.CrossRefGoogle Scholar
Brearley, A.J. (1987a) A natural example of the disequilibrium breakdown of biotite at high temperature: TEM observations and comparison with experimental kinetic data. Mineralogical Magazine , 51, 93106.CrossRefGoogle Scholar
Brearley, A.J. (1987b) An experimental and kinetic study of the breakdown of aluminous biotite at 800ºC: reaction microstructures and mineral chemistry. Bulletin de Minéralogie , 101, 513532.CrossRefGoogle Scholar
Brearley, A.J. and Rubie, D.C. (1990. Effects of H2O on the disequilibrium breakdown of muscovite + quartz. Journal of Petrology , 31, 925956.CrossRefGoogle Scholar
Butler, B.B.C. (1961 Metamorphism and metasomatism of rocks in the Moine Series by a dolerite plug at Glenmore, Ardnamurchan. Mineral ogical Magazine, 32, 866897.CrossRefGoogle Scholar
Dougan, T.W. (1974 Cordierite gneisses and associated lithologies of the Guri area, northwest Guayana Shield, Venezuela. Contributions to Mineralogy and Petrology, 46, 169188.CrossRefGoogle Scholar
Grapes, R.H. (1986 Melting and thermal reconstitution of pelitic xenoliths, Wehr volcano, East Eifel, Germany. Journal of Petrology, 27, 343396.CrossRefGoogle Scholar
Grapes, R.H. (1987 Composition and melting relationships of andalusite in a schist xenolith, Wehr volcano, East Eifel. Neues Jahrbuch für Mineralogie Monatshefte , 550556.Google Scholar
Grapes, R.H. (1991 Aluminous alkali feldspar-bearing xenoliths and the origin of sanidinite, East Eifel, Germany. Neues Jahrbu ch für Mineralogi e Monatshefte , 129143.Google Scholar
Henry, J. (1974 Garnet-cordierite gneisses near the Egersund-Ogna anorthosite intrusion, south-western Norway. Lithos, 7, 207216.CrossRefGoogle Scholar
Hoffer, E. (1978 Melting reactions in aluminous metapelites: stability limits of biotite + sillimanite + quartz in the presence of albite. Neues Jahrbuch für Mineralogie Monatshefte , 396407.Google Scholar
Holdaway, M.J. (1971 Stability of andalusite and the aluminium silicate phase diagram. American Journal of Science, 271, 97133.CrossRefGoogle Scholar
Johannes, W. and Holz, F. (1996 Petrogenesis and Experimental Petrology of Granitic Rocks . Springer-Verlag, Berlin, Heidelberg.CrossRefGoogle Scholar
Johnson, S.E. and Vernon, R.H. (1995 Stepping stones and pitfalls in the determination of an anticlockwise P-T-t-deformation path: the low-P, high-T Coomba Complex, Australia. Journal of Metamorphic Geology, 13, 165183.CrossRefGoogle Scholar
Kars, H., Jansen, J.J.B., Tobi, A.C. and Poorter, R.R.P. (1980 The metapelitic rocks of the polymetamorphic Precambrian of Rogaland, SW Norway – Part II. Mineral relations between cordierite, hercynite and magnetite within the osumilite-in isograd. Contr ibutions to Mine ralogy and Petrology, 74, 235244.CrossRefGoogle Scholar
Pattison, D.D.R. and Tracy, R.J. (1991 Phase equilibria and thermobarometry of metapelites. Pp. 105206 in: Contact Metamorphism (Kerrick, D.M., editor). Reviews in Mineralogy, 26. Mineralogical Society of America, Washington, D.C.CrossRefGoogle Scholar
Pattison, D.D.R., Spear, F.S., Debuhr, C.L., Cheney, J.T. and Guidotti, C.V. (2002 Thermodynamic modeling of the reaction muscovite + cordierite = Al2SiO5 + biotite + quartz + H2O: constraints from natural assemblages and implications for the metapel itic pet rogene tic gr id. Journal of Metamorphic Geology, 20, 99118.CrossRefGoogle Scholar
Rubie, D.C. and Brearley, A.J. (1987 Metastable melting during the breakdown of muscovite + quartz at 1 kbar. Bulletin de Minéralogie, 101, 533549.CrossRefGoogle Scholar
Seifert, F. (1976 Stability of the assemblage cordierite + K feldspar + quartz. Contributions to Mineralogy and Petrology, 57, 179185.CrossRefGoogle Scholar
Smith, D.D.G. (1969 Pyrometamorphism of phyllites by a dolerite plug. Journal of Petrology, 10, 2055.CrossRefGoogle Scholar
Vernon, R.H. (1978 Pseudomorphous replacement of cordierite by symplectic intergrowths of andalusite, biotite and quartz. Lithos, 11, 283289.CrossRefGoogle Scholar
Vernon, R.H. (1988 Sequential growth of cordierite and andalu site porphyr oblast s, Cooma Complex, Australia: microtextural evidence of a prograde reaction. Journal of Metamorphic Geology, 6, 255269.CrossRefGoogle Scholar
Vernon, R.H. and Pooley, G.D. (1981 SEM/microprobe study of some symplectite intergrowths replacing cordierite. Lithos, 14, 7582.CrossRefGoogle Scholar
Worden, R.H., Champness, P.E. and Droop, G.G.T. (1987 Transmission electron microscopy of the pyrometamorphic breakdown of phengite and chlorite. Mineralogical Magazine, 51, 107121.CrossRefGoogle Scholar
Wörner, G. and Fricke, A. (1984 Fluid inclusions in corundum from a contact metamorphic xenolith of the Quaternary Wehr volcano (East Eifel, Germany). Neues Jahrbuch für Mineralogie Monatshefte , 3947.Google Scholar
Wörner, G. and Schmincke, H.-U. (1984 Petrogenesis of a zoned Laacher See tephra. Journal of Petrology, 25, 836851.CrossRefGoogle Scholar
Wörner, G., Schmincke, H.-U. and Schreyer, W. (1982 Crustal xenoliths from the Quaternary Wehr Volcano (East Eifel). Neues Jarhbuch für Mineralogie Abhandlungen, 144, 2955.CrossRefGoogle Scholar
Wyllie, P.J. (1961 Fusion of a Torridonian sandstone by a picrite sill on Soay (Hebrides). Journal of Petrology, 2, 137.CrossRefGoogle Scholar