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Deformation-controlled cation diffusion in compositionally zoned tourmaline

Published online by Cambridge University Press:  05 July 2018

Abstract

The compositional zonation of both undeformed and plastically deformed tourmaline crystals from an amphibolite-facies mylonitic pegmatite from the Sierras Pampeanas (NW Argentina) has been investigated using electron microprobe analysis (EMPA). Undeformed tourmaline shows optical and compositional major and minor element growth zonation with a Ca- and Mg-rich rim zone and an Fe- rich core zone. The tourmaline population of the mylonite consists of crystals which appear undeformed at microscopic scale, and of weakly, moderately, and strongly deformed crystals. Depending on the intensity of plastic deformation, the optical zonation is blurred or absent, and the compositional zonation is less pronounced or destroyed. Plastic deformation mobilizes small cations (Fe2+, Mg2+) more efficiently and at lower deformation intensity than larger cations (Na+, Ca2+). In addition to intra-crystal homogenization, plastic deformation caused variable but generally minor Fe, Mg, Si, Al, Ca, and Na exchange between deformed tourmaline domains and co-existing fluid or solid phases. Dislocation creep is interpreted as the dominant deformation mechanism leading to the homogenization of the initial tourmaline growth zonation. The composition and the degree of homogeneity of deformed tourmaline domains depend on the initial composition of the growth zones, their initial volume ratio, the intensity and homogeneity of plastic deformation, and the size of the mobilized cation. Consequently, the composition of and the element distribution within plastically deformed crystals is not entirely controlled by intensive variables (P-T-X), and therefore not suitable for petrogenetic interpretation.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2005

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References

Best, M.G. (1982) Igneous and Metamorphic Petrology. Freeman and Company, New York, 630 pp.Google Scholar
Brocker, M. and Franz, L. (2000) The contact aureole on Tinos (Cyclades, Greece): tourmaline-biotite geothermometry and Rb-Sr geochronology. Mineralogy and Petrology, 70, 257283.Google Scholar
Büttner, S., Glodny, J., Lucassen, F., Wemmer, K., Erdmann, S., Handler, R. and Franz, G. (2005) Ordovician metamorphism and plutonism in the Sierra de Quilmes metamorphic complex: Implications for the tectonic setting of the northern Sierras Pampeanas (NW Argentina). Lithos, 83, 143181.CrossRefGoogle Scholar
Colopietro, M.R. and Frieberg, L.M. (1987) Tourmaline-biotite as a potential geothermometer for metapelites; Black Hills, South Dakota. Geological Society of America Abstracts, 19, 624.Google Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1992) Introduction to Rock-forming Minerals, 2nd edition. Longman Scientific & Technical, Harlow, Essex, UK, pp. 130135.Google Scholar
Evans, B. and Kohlstedt, D.L. (1995) Rheology of rocks. Pp. 148165 in: Rock Physics & Phase Relations -A Handbook of Physical Constants (Ahrens, T.J., editor). AGU Reference Shelf, 3, American Geophysical Union, Washington, D.C.Google Scholar
Foit, F.F. Jr, Fuchs, Y. and Myers, P.E. (1989) Chemistry of alkali-deficient schorls from two tourmaline-dumortierite deposits. American Mineralogist, 74, 13171324.Google Scholar
Green, H.W., Griggs, D.T. and Christie, J.M. (1970) Syntectonic annealing and recrystallization of fine-grained quartz aggregates. Pp. 272335 in: Experimental and Natural Rock Deformation (Paulitsch, P., editor). Springer-Verlag, Berlin.Google Scholar
Hawthorne, F. (1996) Structural mechanisms for light-element variations in tourmaline. The Canadian Mineralogist, 34, 123132.Google Scholar
Henry, D.J. and Dutrow, B.L. (1996) Metamorphic tourmaline and its petrologic application. Pp. 503558 in: Boron — Mineralogy, Petrology and Geochemistry (Grew, E.S. and Anovitz, L.M., editors). Reviews in Mineralogy, 33, Mineralogical Society of American, Washington, D.C.CrossRefGoogle Scholar
Holdaway, M.J. and Mukhopadhyay, B. (1993) A re-evaluation of the stability relations of andalusite. Thermochemical data and phase diagram for the aluminium silicates. American Mineralogist, 78, 298315.Google Scholar
Holland, T.J.B. (1979) Experimental determination of the reaction Paragonite = Jadeite + Kyanite + H2O, and internally consistent thermodynamic data for part of the system Na2O—A12O3—SiO2—H2O, with application to eclogites and blueschists. Contributions to Mineralogy and Petrology, 68, 292301.CrossRefGoogle Scholar
Kawakami, T. (2001) Tourmaline breakdown in the migmatite zone of the Ryoke metamorphic belt, SW Japan. Journal of Metamorphic Geology, 19, 6175.CrossRefGoogle Scholar
Kretz, R. (1983) Symbols for rock-forming minerals. American Mineralogist, 68, 277279.Google Scholar
Kruhl, J.H. (1998) Prism- and basal-plane parallel subgrain boundaries in quartz: a microstructural geothermobarometer: Reply. Journal of Metamorphic Geology, 16, 142146.Google Scholar
Lister, G.S. and Williams, P.F. (1979) Fabric development in shear zones: theoretical control and observed phenomena. Journal of Structural Geology, 1, 283297.CrossRefGoogle Scholar
Poirier, J.P. (1995) Plastic rheology of crystals. Pp. 237247 in: Rock Physics & Crystallography - A Handbook of Physical Constants (Ahrens, T.J., editor). AGU Reference Shelf 2, American Geophysical Union, Washington, D.C.Google Scholar
Sander, B. (1930) Gefügekunde der Gesteine, pp. 6872, Springer-Verlag, Wien.CrossRefGoogle Scholar
Schmid, S.M. and Casey, M. (1986) Complete fabric analysis of some commonly observed quartz C-axis patterns. Geophysical Monograph, 36, 263286.Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica, A32, 751767.CrossRefGoogle Scholar
Spear, F.S. (1993) Metamorphic Phase Equilibria and Pressure-temperature-time Paths, pp. 575639, Monograph, Mineralogical Society of America, Washington, D.C.Google Scholar
Spear, F.S. and Cheney, J.T. (1989) A petrogenetic grid for pelitic schists in the system SiO2-Al2O3-FeO-MgO-K2O-H2O. Contributions to Mineralogy and Petrology, 101, 149164.CrossRefGoogle Scholar
Stünitz, H. (1998) Syndeformational recrystallisation — dynamic or compositionally induced? Contributions to Mineralogy and Petrology, 131, 219236.Google Scholar
v. Goerne, G. and Franz, G. (2000) Synthesis of Ca-tourmaline in the system CaO-MgO-Al2O3-SiO2-B2O3-H2O -HCl. Mineralogy and Petrology, 69, 161182.CrossRefGoogle Scholar
v. Goerne, G., Franz, G. and Wirth, R. (1999) Hydrothermal synthesis of large dravite crystals by the chamber method. European Journal of Mineralogy, 11, 10611077.CrossRefGoogle Scholar
v. Goerne, G., Franz, G. and Heinrich, W. (2001) Synthesis of tourmaline solid solutions in the system Na2O-MgO-Al2O3-SiO2-B2O3-H2O-HCl and the distribution of Na between tourmaline and fluid at 300 to 700°C and 200 MPa. Contributions to Mineralogy and Petrology, 141, 160173.CrossRefGoogle Scholar
van Groos, A.F.K. and Heege, J.P.T. (1973) The high-low quartz transition up to 10 kilobars pressure. Journal of Geology, 81, 717724.CrossRefGoogle Scholar
Veličkov, B. (2002) Kristallchemie von Fe, Mg-Turmalinen: Synthese und spektroskopische Untersuchungen. PhD thesis, Technische Universität Berlin, http://edocs.tu-berlin.de/diss/ar-chiv_2002.html#oben.Google Scholar
Voll, G. (1976) Recrystallization of quartz, biotite, and feldspars from Erstfeld to the Leventina Nappe, Swiss Alps, and its geological significance. Schweizerische Mineralogische und Petrographische Mitteilungen, 56, 641647.Google Scholar
Yund, R.A. and Tullis, J. (1991) Compositional changes of minerals associated with dynamic recrystallisation. Contributions to Mineralogy and Petrology, 108, 346355.CrossRefGoogle Scholar