Thin Amorphous Intergranular Layers at Mineral Interfaces in Xenoliths: the Early Stage of Melting

  • Richard Wirth
  • Leander Franz
Part of the Petrology and Structural Geology book series (PESG, volume 11)


The presence of intergranular glassy layers and pockets along mineral interfaces, on microfractures and as inclusions in minerals in mantle peridotite xenoliths from different locations is revealed by optical microscopy and transmission electron microscopy (TEM). All these glasses represent former melts, that is confirmed by electron diffraction as well as their typical geochemical signatures. Often very thin glass layers are present on grain boundaries and show characteristic chemical compositions that strongly depend on the adjacent minerals. The composition of these layers differs distinctly from the bulk melt composition of partial melt experiments or from the compositions of wider melt pools of glasses observed in other xenoliths. Furthermore, a relation of these glasses to the adjacent host basalt can be excluded by the distinctly different geochemistry of the melts. The chemical composition of the melt changes with increasing thickness of the glass layers, which is due to mixing processes of the different types of glasses in the xenoliths. Wider melt films (>1 µm) are more similar to glasses observed in large melt pools and veins given in the literature as well as partial melting experiments. Thus, the chemical composition varies from that of the very first melt at different interfaces to the bulk composition of partial melts created by experiments depending on the melt film thickness. Melts are probably formed by grain boundary melting due to lattice mismatch and impurity segregation in the xenolith triggered by decompression processes during the uplift of the xenolith. This point is consistent with the corrosion textures and the absence of chemical equilibrium between melt and adjacent olivine crystals. Chemical equilibrium is only found for very few melt films along olivine boundaries and melt inclusions in olivine neoblasts. These early melts were generated during thermal overprint and dynamic recrystallisation of the xenolith in the mantle. The occurrence of melt on grain boundaries has important geological and petrological implications. Intergranular layers give an insight into the very first melting processes and the development of melt composition with time and degree of partial melting. Furthermore, melt films on interfaces are suggested to have an important significance for the rheology of the mantle by distinctly increasing the creep rate of the rock. Finally, diffusion processes may be distinctly enhanced by the presence of melt and may give way for a very fast reequilibration of the mineral chemistry.

Key words

grain boundary structure glass layer melt film interface melting TEM 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Behrmann, J., G. Drozdzewski, T. Heinrichs, M. Huch, W. Meyer, and O. Oncken, Crustal balanced cross sections through the Variscan fold belt, Germany: the central EGT-segment, Tectonophysics, 196, 1–21, 1991.CrossRefGoogle Scholar
  2. Bonnell, D.A., T.Y. Tien, and M. Rühle, Controlled crystallisation of the amorphous phase in silicon nitride ceramics, J. Am. Ceram. Soc., 70, 460–465, 1987.CrossRefGoogle Scholar
  3. Brey, G.P., and T. Köhler, Geothermobarometry in four phase lherzolite. II. New thermobarometers, and practical assessment of existing thermobarometers, J. Petrol., 31, 1353–1378, 1990.Google Scholar
  4. Brydson R., S.C. Chen, F.L. Riley, S.J. Milne, X. Pan, and M. Rühle, Microstructure and chemistry of intergranular glass films in liquid-phase-sintered alumina, J. Am. Ceram. Soc. 81, 369–379, 1998.CrossRefGoogle Scholar
  5. Cahn, J.W., and J.E. Hillard, Free energy of a non uniform system. I. Interfacial free energy., J. Chem. Phys., 28, 258, 1958.CrossRefGoogle Scholar
  6. Carter C.B., and D.L. Kohlstedt, Electron irradiation damage in natural quartz grains, Phys. Chem. Minerals, 7, 110–116, 1981.CrossRefGoogle Scholar
  7. Chakraborty S., Diffusion in silicate melts, in: Reviews in Mineralogy 32, edited by J.F. Stebbins, P.F. McMillan, and D.B. Dingwell, pp. 411–503, 1995.Google Scholar
  8. Chiang, Y., and W.D. Kingery, Grain boundary migration in nonstoichiometric solid solutions of magnesium aluminate spinel: II effects of grain boundary nonstoichiometry, J. Am. Ceram. Soc., 75,1153–1158, 1990.CrossRefGoogle Scholar
  9. Cinibulk, M.K., G. Thomas, and S.M. Johnson, Fabrication and secondary phase crystallisation of RE disilicate-silicon nitride ceramics, J. Am. Ceram. Soc., 75, 2037–2043, 1992.CrossRefGoogle Scholar
  10. Clarke, D.R., On the equilibrium thickness of intergranular glass phases in ceramic materials, J. Am. Ceram. Soc., 70, 15–22, 1987.CrossRefGoogle Scholar
  11. Clarke, D.R., T.M. Shaw, A.P. Philipse, and G.G. Horn, Possible electric double-layer contribution to the equilibrium thickness of intergranular glass films in polycrystalline ceramics, J. Am. Ceram. Soc., 76, 1201–1204, 1993.CrossRefGoogle Scholar
  12. Das Chowdhury, K., R.W. Carpenter, W. Braue, J. Liu, and H. Ma, Chemical and structural widths of interface and grain boundaries in silicon nitride-silicon carbide whisker composites, J. Am. Ceram. Soc., 78, 2579–2592, 1995.CrossRefGoogle Scholar
  13. Cmíral, M., J.D. Fitz Gerald, and U.H. Faul, A close look at dihedral angles and melt geometry in olivine-basalt aggregates: a TEM study, Contrib. Mineral. Petrol., 130, 336–345, 1998.CrossRefGoogle Scholar
  14. Cooper, R.F., and D.L. Kohlstedt, Interfacial energies in the olivine-basalt system, in: High pressure research in geophysics, edited by S. Akimoto, and M.H. Manghnani, pp. 217–228, Adv. Earth Planet. Sci., 1982.CrossRefGoogle Scholar
  15. Dimanov, A., G. Dresen, and R. Wirth, Creep behaviour of partially molten polycrystalline labradorite, Terra Nova, Abstract Supplement 1, p. 12, 1998.Google Scholar
  16. Drury, M.R., and J.D. Fitz Gerald, Grain boundary melt films in an experimentally deformed olivine-orthopyroxene rock: implications for melt distribution in the upper mantle rocks, Geophys. Res. Lett., 23, 701–704, 1996.CrossRefGoogle Scholar
  17. Dupas, C., Etude par microscopie électronique en transmission analytique d’olivines et spinelles déformés expérimentallement aux conditions (P-T) de la zone transitione du manteau, 146 pp., Thesis no 1280, l’Université de Rennes, 1994.Google Scholar
  18. Edgar, A.D., F.E. Lloyd, D.M. Forsyth and R.L. Barnett, Origin of glass in upper mantle xenoliths from quarternary volcanics of Gees, West Eifel, Germany, Contrib. Mineral. Petrol., 103, 277–286, 1989.CrossRefGoogle Scholar
  19. Egerton, R.F., Electron energy-loss spectroscopy in the electron microscope, pp. 301–312, Plenum Press New York, 1996.Google Scholar
  20. Ficke, B., Petrologische Untersuchungen an tertiären basaltischen bis phonolitischen Vulkaniten der Rhön, Tschermaks Mineral. Petrogr. Mitt., 7, 337–436, 1961.CrossRefGoogle Scholar
  21. Franke, W. and O. Oncken, Geodynamic evolution of the North-Central Variscides — a comic strip, in: The European geotraverse: Integrative studies, edited by R. Freeman, P. Giese, and St. Mueller, pp. 187–194, Results from the Fifth Study Centre, Rauischholzhausen (26 March–7 April 1990), European Science Foundation, Strasbourg, 1990.Google Scholar
  22. Franz, L., G.P. Brey and M. Okrusch, Reequilibration of ultramafic xenoliths from Namibia by metasomatic processes at the mantle boundary, J. Geology, 104, 599–615, 1996.CrossRefGoogle Scholar
  23. Franz, L., W. Seifert and W. Kramer, Thermal evolution of the mantle underneath the Mid-German Crystalline Rise: Evidence from mantle xenoliths from the Rhön area (Central Germany)., Mineral. Petrol., 61,1–25, 1997.CrossRefGoogle Scholar
  24. Franz, L., and Wirth R., Thin intergranular melt films and melt pockets in spinel peridotite xenoliths from the Rhön area (Germany): early stage of melt generation by grain boundary melting, Contrib. Mineral. Petrol., 129, 268–283, 1997.CrossRefGoogle Scholar
  25. Frey, A.F., and M. Prinz, Ultramafic inclusions from San Carlos, Arizona: petrologic and geochemical data bearing on their petrogenesis, Earth Planet. Sci. Lett., 38, 126–176, 1978.CrossRefGoogle Scholar
  26. Frey, A.F., and D.H. Green, The mineralogy, geochemistry and origin of lherzolite inclusions in Victorian basanites, Geochimica et Cosmochimica Acta, 38, 1023–1059, 1974.CrossRefGoogle Scholar
  27. Gaetani, G.A., and T.L. Gove, The influence of water on melting of mantle peridotite, Contrib. Mineral. Petrol., 131, 323–346, 1998.CrossRefGoogle Scholar
  28. Gamble, A.J., and P.R. Kyle, The origins of glass and amphibole in spinel-wehrlite xenoliths from Foster Crater, McMurdo Volcanic Group, Antarctica, Journal of Petrology, 28, 755–779, 1987.Google Scholar
  29. Girod, M., J.M. Dautria and R. de Giovanni, A first insight into the constitution of the upper mantle under Hoggar Area (Southern Algeria): the lherzolite xenoliths in the alkali basalts, Contrib. Mineral. Petrol., 77, 66–73, 1981.CrossRefGoogle Scholar
  30. Gleiter, H., and B. Chalmers, High-angle grain boundaries, in: Progress in material science, 16, edited by B. Chalmers, J.W. Christian and T.B. Massalski, pp. 1–274, Pergamon Press, Oxford, 1972.Google Scholar
  31. Gleiter, H., Microstructure, in: Physical Metallurgy, edited by R.W. Cahn and P. Haasen, pp. 650–712, third, revised and enlarged edition, Elsevier, 1983.Google Scholar
  32. Goldstein, J.I,. and D.B.Williams, Quantitative X-ray analysis, in: Principles of analytical electron microscopy, edited by D.C. Joy, A.D. Romig and J.I. Goldstein, pp. 155–218, Plenum Press, New York, 1989.Google Scholar
  33. Green, D.H., Experimental melting studies on a model upper mantle composition at high pressure under water-saturated and water-undersaturated conditions, Earth and Planetary Sci. Letters, 19, 37–53, 1973.CrossRefGoogle Scholar
  34. Hall, E.L., Compositional analysis of interfaces using X-ray spectroscopy, Microscopy Society of America Bulletin, 24, 359–370, 1994.Google Scholar
  35. Harte, B., Rock nomenclature with particular relation to deformation and recrystallisation textures in olivine-bearing xenoliths, J. Geology, 85, 279–288, 1977.CrossRefGoogle Scholar
  36. Harte, B., R.H. Hunter and P.D. Kinny, Melt geometry, movement and crystallisation, in relation to mantle dykes, veins and metasomatism, Phil. Trans. Royal. Soc. Lond. A, 342, 1–21, 1993.CrossRefGoogle Scholar
  37. Heinrich, W. and T. Besch, Thermal history of the upper mantle beneath a young back-arc extensional zone: ultramafic xenoliths from San Luis Potosi, Central Mexico, Contrib. Mineral. Petrol., 111, 126–142, 1992.CrossRefGoogle Scholar
  38. Hess, P.C., Thermodynamics of thin fluid films, J. Geophys. Res., 99, 7219–7229, 1994.CrossRefGoogle Scholar
  39. Herzberg, C., T. Gasparik, and H. Sawamoto, Origin of mantle peridotite: constraints from melting experiments to 16.5 Gpa, J. Geophys. Res., 95, 15,799–15,803, 1990.CrossRefGoogle Scholar
  40. Hirose, K., and T. Kawamota, Hydrous partial melting of lherzolite at 1 GPa: The effect of H2O on the genesis of basaltic magmas, Earth and Planetary Sci. Letters, 133, 463–473, 1995.CrossRefGoogle Scholar
  41. Hirose, K., and I. Kushiro, Partial melting of dry peridotites at high pressures: determination of compositions of melts segregated from peridotite using aggregates of diamond, Earth and Planetary Sci. Letters, 114, 477–489, 1993.CrossRefGoogle Scholar
  42. Hirth, G., and D.L. Kohlstedt, Experimental constraints on the dynamics of the partially molten upper mantle: deformation in the diffusion creep regime, J. Geophys. Res., 100, 1981–2001, 1995.CrossRefGoogle Scholar
  43. Hobbs, L.W., and M.R. Pascucci, Radiolysis and defect structure in electron-irradiated alpha-quartz, Journal de Physique, 41, C6-237–C6-242, 1980.Google Scholar
  44. Inui, H., H. Mori, T. Sakata and H. Fujita, Electron irradiation induced crystalline -to-amorphous transition in quartz single crystals, Journal of Non-Crystalline Solids,, 116, 1–15, 1990.CrossRefGoogle Scholar
  45. Irving, A.J. and H.D. Green, Geochemistry and petrogenesis of the Newer Basalts of Victoria and South Australia, J. Geol. Soc. Aust., 23, 45, 1976.CrossRefGoogle Scholar
  46. Jin Zhen-Ming, H.W. Green, and Y. Zhou, Melt topology in partially molten mantle peridotite during ductile deformation, Nature, 372, 164–167, 1994.CrossRefGoogle Scholar
  47. Jones, A.P., J.V. Smith, and B.J. Dawson, Glasses in mantle xenoliths from Olmani, Tanzania, Journal of Geology, 91, 161–178, 1983.Google Scholar
  48. Jurewicz, S.R., and A.J.G. Jurewicz, Distribution of apparent angles on random section with emphasis on dihedral angle measurements, J. Geophys. Res., 91, 9277–9282, 1986.CrossRefGoogle Scholar
  49. Keblinski, P., S.R. Phillpot, D. Wolf, and H. Gleiter, On the thermodynamic stability of amorphous intergranular films in covalent materials, J. Amer. Ceramic. Soc., 80, 717–732, 1997.CrossRefGoogle Scholar
  50. Kleebe, H.-J., and G. Pezzotti, Anion segregation at Si3N4 interfaces studied by high-resolution transmission electron microscopy and internal friction measurements: a model system, in: Ceramic Microstructure: Control at the atomic level, edited by A.P. Tomsia and A. Glaeser, pp. 107 – 114, Plenum Press, NY & London, 1998.Google Scholar
  51. Klügel, A., Reactions between mantle xenoliths and host magma beneath La Palma (Canary Islands): constraints on magma ascent rates and crustal reservoirs, Contrib. Mineral. Petrol., 131,231–251, 1998.Google Scholar
  52. Kohlstedt, D.L., Structure, rheology and permeability of partially molten rocks at low melt fractions, in: Mantle Flow and Melt Generation at Mid-Ocean ridges, Geophys. Monogr. Ser., vol. 71, edited by J. Phipps Morgan, D.K. Blackman and J.M. Sinton, pp. 103–121, AGU, Washington D.C., 1992.CrossRefGoogle Scholar
  53. Kronberg, M.L., and F.H. Wilson, Secondary recrystallization in copper, Trans. AIME, 185, 501, 1949.Google Scholar
  54. Köhler, T., and G.P. Brey, Calcium exchange between olivine and clinopyroxene calibrated as a geothermobarometer for natural peridotites from 2 to 60 kb with applications, Geoch. Cosmoch. Acta, 54, 2375–2388, 1990.CrossRefGoogle Scholar
  55. Lange, F., Liquid-phase sintering: are liquids squeezed out from between compressed particles?, J. Am. Ceram. Soc., 65, C-23, 1982.CrossRefGoogle Scholar
  56. Laporte, D., Wetting behaviour of partial melts during crustal anatexis: the distribution of hydrous silicic melt in polycrystalline aggregates of quartz, Contrib. Mineral. Petrol., 116, 486–499, 1994.CrossRefGoogle Scholar
  57. Laporte, D., C. Rapaille, and A. Provost, Wetting angles, equilibrium melt geometry, and the permeability threshold of partially molten crustal protoliths, in: Granite: From segregation of melt to emplacement fabrics, edited by J..L. Bouchez, D,H,W, Hutton, and W.E. Stephens, pp. 31–54, Kluwer Academic Publishers, Dordrecht, 1997.Google Scholar
  58. Lippolt, H.W., K-Ar- Untersuchungen zum Alter des Rhön-Vulkanismus, Fortschr. Mineral., 56, Beiheft 1,85, 1978.Google Scholar
  59. Maaløe, S., and I. Printzlau, Natural partial melting of spinel lherzolite, J. Petrology, 20, 727–741, 1978.Google Scholar
  60. Martin, B., O.W. Flörke, E. Kainka, and R. Wirth R., Electron irradiation damage in quartz, SiO2, Phys. Chem. Minerals, 23, 409–417, 1996.CrossRefGoogle Scholar
  61. Mott, N.F., Slip at grain boundaries and grain growth in metals, Proc. Phys. Soc. London, 60, pp. 391, 1948.CrossRefGoogle Scholar
  62. Mysen, B.O., and A.L. Boettcher, Melting of a hydrous mantle: II. Geochemistry of crystals and liquids formed by anatexis of mantle peridotite at high pressures and high temperatures as a function of controlled activities of water, hydrogen, and carbon dioxide, J. Petrology, 16, 549–593, 1975.Google Scholar
  63. Odling, N.W.A., D.H. Green, and B. Harte, The determination of partial melt compositions of peridotitic systems by melt inclusion synthesis, Contrib. Mineral. Petrol., 129, 209–221, 1997.CrossRefGoogle Scholar
  64. Ohje, T., T. Hirano, A. Nakahira, and K. Niihara, Particle/matrix interface and its role in creep inhibition in alumina/silicon carbide nanocomposites, J. Am. Ceram. Soc., 79, 33–45, 1996.CrossRefGoogle Scholar
  65. Ollier, C.D., and E.B. Joyce, Geo morphology of the Western District volcanic plains, lakes and coastline in: Regional guide to Victorian geology, edited by J. McAndrew and M. A. H. Marsden, pp. 224–239, University of Melbourn, Melbourn, 1973.Google Scholar
  66. Raterron, P., G.Y. Bussod, N. Doukhan, and J.C. Doukhan, Early partial melting in upper mantle: An A.E.M. study of a lherzolite experimentally annealed at hypersolidus conditions, Tectonophysics, 279,79–91, 1997.CrossRefGoogle Scholar
  67. Pezzotti, G., K. Ota, and H.J. Kleebe, Grain boundary relaxation in high-purity silicon nitride, J. Am. Ceram. Soc., 79, 2237–2246, 1996.CrossRefGoogle Scholar
  68. Schiano, P., R. Clocchiatti, N. Shimizu, R.C. Maury, K.P. Jochum, and A.W. Hofmann, Hydrous, silica-rich melts in the sub-arc mantle and their relationship with erupted arc lavas, Nature, 377, 595–600, 1995.CrossRefGoogle Scholar
  69. Sutton, A.P., and R.W. Balluffi, Interfaces in crystalline materials, Monographs on the physics and chemistry of materials 51, 852 pp., Clarendon Press, Oxford, 1995.Google Scholar
  70. Szabó, C., R.J. Bodnar, and A.V. Sobolev, Metasomatism associated with subduction related volatile-rich silicate melt in the upper mantle beneath the Nógrád-Gömör Volcanic Field, Northern Hungary/Southern Slovakia: Evidence from silicate melt inclusions, Eur. J. Mineral., 8, 881–899, 1996.Google Scholar
  71. Takahashi, E., Melting of dry peridotite KLB-1 up to 14 GPa: Implications on the origin of peridotitic upper mantle, J. Geophys. Res., 91, 9367–9382, 1986.CrossRefGoogle Scholar
  72. Vaughan, P.J., D.L. Kohlstedt, and H.S. Waff, Distribution of the glass phase in hot-pressed, olivine-basalt aggregates: An electron microscopy study, Contrib. Mineral.Petrol., 81, 253–261, 1982.CrossRefGoogle Scholar
  73. Waff, H.S., and J.R. Bulau, Equilibrium fluid distribution in an ultramafic partial melt under hydrostatic stress conditions, J. Geophys. Res., 84, 6109–6114, 1979.CrossRefGoogle Scholar
  74. Waff, H.S., and U.H. Faul, Effects of crystalline anisotropy on fluid distribution in ultramafic partial melts, J. Geophys. Res., 97, 9003–9014, 1992.CrossRefGoogle Scholar
  75. White, R.E., Ultramafic inclusions in basaltic rocks from Hawaii, Contrib. Mineral. Petrol., 12, 245–314, 1966.CrossRefGoogle Scholar
  76. Wiechert, U., D.A. Ionov, and K.H. Wedepohl, Spinel peridotite xenoliths from the Atsagin-Dush volcano, Dariganga lava plateau, Mongolia: a record of partial melting and cryptic metasomatism in the upper mantle, Contrib. Mineral. Petrol., 126, 345–364, 1997.CrossRefGoogle Scholar
  77. Wilkinson, D.S., Creep mechanisms in multiphase ceramic materials, J. Am Ceram. Soc., 81, 275–299, 1998.CrossRefGoogle Scholar
  78. Wirth, R., Thin amorphous films (1–2 nm) at olivine grain boundaries in mantle xenoliths from San Carlos, Arizona, Contrib. Mineral. Petrol., 124, 44–54, 1996.CrossRefGoogle Scholar
  79. Wulff-Pedersen, E., E.R. Neumann, and B.B.Jensen, The upper mantle under La Palma, Canary Islands: formation of Si-K-Na-rich melt and its importance as a metasomatic agent, Contrib. Mineral. Petrol., 125, 113–139, 1996.CrossRefGoogle Scholar
  80. Xu, Y., J.C.C. Mercier, C. Lin, L. Shi, M.A. Menzies, J.V. Ross, and Harte B., K-rich glass bearing wehrlite xenoliths from Yitong, North-eastern China: petrological and chemical evidence for mantle metasomatism, Contrib. Mineral Petrol., 125, 406–420, 1996.CrossRefGoogle Scholar
  81. Yaxley, G.M., V. Kamenetsky, D.H. Green, and T.J. Falloon, Glasses in mantle xenoliths from Western Victoria, Australia, and their relevance to mantle processes, Earth Planet. Sci. Lett., 148, 433–446, 1997.CrossRefGoogle Scholar
  82. Zinngrebe, E., and S.F. Foley, Metasomatism in mantle xenoliths from Gees, West Eifel, Germany: evidence for the genesis of calc-alkaline glasses and metasomatic Ca-enrichment, Contrib. Mineral. Petrol., 122, 79–96, 1995.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2000

Authors and Affiliations

  • Richard Wirth
    • 1
  • Leander Franz
    • 2
  1. 1.GeoForschungsZentrum PotsdamPotsdamGermany
  2. 2.TU Bergakademie FreibergFreibergGermany

Personalised recommendations