Clays and Clay Minerals

, Volume 39, Issue 3, pp 225–233 | Cite as

Metastability in Near-Surface Rocks of Minerals in The System Al2O3-SiO2-H2O

  • Lawrence M. Anovitz
  • Dexter Perkins
  • Eric J. Essene


Gibbs free energies for phases in the system Al2O3-SiO2-H2O have been calculated from reversed experiments in order to correct earlier values and to calculate a phase diagram consistent with more recent experiments. An internally consistent diagram could not be calculated that agreed with all published experiments, and choices of preferred data were made. The following Gibbs free energies, relative to the elements at STP (298.15 K, 1 bar), have been derived

The above values were calculated assuming literature values for corundum, quartz, and H2O (v).

Examination of available thermodynamic, experimental, and observational data on the aluminum hydroxides gibbsite, boehmite, bayerite, and nordstrandite suggests that these minerals are metastable with respect to diaspore + water at STP and at higher temperatures. Similarly, halloysite and dickite are metastable with respect to kaolinite at these conditions. The occurrence of these minerals in soils must therefore be ascribed to nonequilibrium processes, and the use of equilibrium phase diagrams to explain their occurrence is inappropriate.

Key Words

Aluminum hydroxide Dickite Gibbs free energy Halloysite Kaolinite Metastability Phase equilibria Pyrophyllite. 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Apps, J. A., Neil, J. M., and Jun, C.-H. (1989) Thermochemical properties of gibbsite, bayerite, boehmite, diaspore and the aluminate ion between 0 and 350°C: Prepared for U.S. Nuclear Regulatory Commission, NUREG/CR-5271, Lawrence Berkeley Laboratory LBL-21482, 97 pp.CrossRefGoogle Scholar
  2. Barany, R. and Kelley, K. K. (1961) Heats and free energies of formation of gibbsite, kaolinite, halloysite, and dickite: U.S. Bur. Mines Rept. Inv. 5825, 1–13.Google Scholar
  3. Barnhisel, R. I. and Rich, C. I. (1965) Gibbsite, bayerite, and nordstrandite formation as affected by anions, pH, and mineral surfaces: Soil Sci. Soc. Amer. Proc. 29, 531–534.CrossRefGoogle Scholar
  4. Berman, R. G. (1988) Internally consistent thermodynamic data set for minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO2: J. Petrol. 29, 445–522.CrossRefGoogle Scholar
  5. Bosmans, H. H. (1970) Unit cell and crystal structure of nordstrandite, Al(OH)3: Acta Crystallogr. B26, 649–652.CrossRefGoogle Scholar
  6. Brace, W. F., Scholz, C. H., and Lamori, P. N. (1969) Isothermal compressibilities of kyanite, andalusite, and sillimanite from synthetic aggregates: J. Geophys. Res. 74, 2089–2098.CrossRefGoogle Scholar
  7. Burnham, C. W., Holloway, J. R., and Davis, N. F. (1969) Thermodynamic properties of water to 1,000°C and 10,000 bars: Geol. Soc. Amer. Spec. Pap. 137, 96 pp.Google Scholar
  8. Bye, J. C. and Robinson, J. G. (1964) Crystallization processes in aluminum hydroxide gels: Kolloid-Z.Z. Polym. 198, 53–60.CrossRefGoogle Scholar
  9. Chesworth, W. (1972) The stability of gibbsite and boehmite at the surface of the Earth: Clay & Clay Minerals 20, 369–374.CrossRefGoogle Scholar
  10. Chesworth, W. (1975) Soil minerals in the system Al2O3-SiO2-H2O: Phase equilibrium model: Clays & Clay Minerals 23, 55–60.CrossRefGoogle Scholar
  11. Chesworth, W. (1978) Comments on a working model of some equilibria in the system alumina-silica-water by H. W. Day: Amer. J. Sci. 278, 1018–1019.CrossRefGoogle Scholar
  12. Chesworth, W. (1980a) Are considerations of mineralogical equilibrium relevant to pedology? Evidence from a weathered granite in central France: Soil Sci. 130, 290–292.CrossRefGoogle Scholar
  13. Chesworth, W. (1980b) The haplosoil system: Amer. J. Sci. 280, 969–985.CrossRefGoogle Scholar
  14. Clark, S. P., Jr. (1966) Handbook of physical constants: Geol. Soc. Amer. Mem. 97, 587 pp.Google Scholar
  15. Dachille, F. and Gigi, P. (1983) Two high-pressure Al(OH)3 phases and contributions to the Al-Al2O3-H2O system: High Temp. High Pres. 15, 657–675.Google Scholar
  16. Day, H. W. (1976) A working model of some equilibria in the system alumina-silica-water: Amer. J. Sci. 276, 1254–1284.CrossRefGoogle Scholar
  17. Fyfe, W. S. and Hollander, M. A. (1964) Equilibrium dehydration of diaspore at low temperatures: Amer. J. Sci. 262, 709–712.CrossRefGoogle Scholar
  18. Fyfe, W. S., Turner, F. J., and Verhoogen, J. (1958) Meta-morphic reactions and metamorphic facies: Geol. Soc. Amer. Mem. 75, 21–51.Google Scholar
  19. Haas, H. (1972) Diaspore-corundum equilibria determined by epitaxis of diaspore on corundum: Amer. Mineral. 57, 1375–1385.Google Scholar
  20. Haas, H. and Holdaway, M. J. (1973) Equilibria in the system Al2O3-SiO2-H2O involving the stability limits of pyrophyllite and thermodynamic data of phyrophyllite: Amer. J. Sci. 273, 449–461.CrossRefGoogle Scholar
  21. Haas, J. L., Jr., Robinson, G. R., Jr., and Hemingway, B. R. (1981) Thermodynamic tabulations for selected phases in the system CaO-Al2O3-SiO2 at 101.325 kPa (1 atm) between 273.15 and 1800 K: J. Phys. Chem. Ref. Data 10, 575–669.CrossRefGoogle Scholar
  22. Hathaway, J. C. and Schlanger, S. O. (1965) Nordstrandite, Al2O3 · 3H2O, from Guam: Amer. Mineral. 50, 1029–1037.Google Scholar
  23. Helgeson, H. C., Delaney, J. M., Nesbitt, H. W., and Bird, D. K. (1978) Summary and critique of the thermodynamic properties of rock-forming minerals: Amer. J. Sci. 278-A, 229 pp.Google Scholar
  24. Hem, J. D. and Roberson, C. E. (1967) Form and stability of aluminum hydroxide complexes in dilute solutions: U.S. Geol. Surv. Water Supply Pap. 1827-A, 55 pp.Google Scholar
  25. Hemingway, B. S. (1982) Gibbs free energies of formation for bayerite, nordstrandite, Al(OH)2+, and Al(OH)2+, aluminum mobility, and the formation of bauxites and laterites: in Adv. Phys. Geochemi. 2, S. K. Saxena, ed., Springer-Verlag, New York, 285–316.Google Scholar
  26. Hemingway, B. S. and Robie, R. A. (1973) A calorimetric determination of the standard enthalpies of formation of huntite, CaMg(CO3)4 and artinite, Mg2(OH)2CO2 · 3H2O and their standard Gibbs free energies of formation: U.S. Geol. Surv. J. Res. 1, 535–541.Google Scholar
  27. Hemingway, B. S., Robie, R. A., and Kittrick, J. A. (1978) Revised values for the Gibbs free energy of formation of Al(OH)4-(aq), diaspore, boehmite and bayerite at 298.15 K and 1 bar, the thermodynamic properties of kaolinite to 800 K and 1 bar, and the heats of solution of several gibbsite samples: Geochim. Cosmochim. Acta 42, 1533–1543.CrossRefGoogle Scholar
  28. Hemingway, B. S. and Sposito, G. (1990) Inorganic aluminum-bearing solid phases: in The Environmental Chemistry of Aluminum, G. Sposito, ed., CRC Press Inc., Boca Raton, Florida (in press).Google Scholar
  29. Hemley, J. J., Montoya, J. W., Marinenko, J. W., and Luce, R. W. (1980) Equilibria in the system Al2O3-SiO2-H2O and some general implications for alteration/mineralization processes: Econ. Geol. 75, 210–228.CrossRefGoogle Scholar
  30. Holdaway, M. J. (1971) The stability of andalusite and the aluminosilicate phase diagram: Amer. J. Sci. 257, 563–573.Google Scholar
  31. Hsu, P. H. (1977) Aluminum hydroxides and oxyhydroxides: in Minerals in Soil Environments, J. B. Dixon and S. B. Weed, eds., Soil Soc. Amer., Madison, Wisconsin, 145–180.Google Scholar
  32. Huang, W. H. (1974) Stabilities of kaolinite and halloysite in relation to weathering of feldspars and nepheline in aqueous solution: Amer. Mineral. 59, 365–371.Google Scholar
  33. Jamieson, J. C. and Olinger, B. (1969) Pressure-temperature studies of anatase, brookite, and rutile and TiO2(II): A discussion: Amer. Mineral. 54, 1477–1480.Google Scholar
  34. Jiang, W.-T., Essene, E. J., and Peacor, D. R. (1990) A transmission electron microscopic study of co-existing pyrophyllite and muscovite: Direct evidence for the metast-ability of illite: Clays & Clay Minerals 38, 225–240.CrossRefGoogle Scholar
  35. Kerrick, D. M. (1968) Experiments on the upper stability of pyrophyllite at 1.8 kb and 3.9 kb pressure: Amer. J. Sci. 206, 204–214.CrossRefGoogle Scholar
  36. Kerrick, D. M. and Jacobs, G. K. (1981) A modified Redlich-Kwong equation for H2O, CO2 and their mixtures at elevated pressures and temperatures: Amer. J. Sci. 281, 735–767.CrossRefGoogle Scholar
  37. Kitterick, J. A. (1966) Free energy of formation of kaolinite from solubility measurements: Amer. Mineral. 51, 1457–1466.Google Scholar
  38. Kitterick, J. A. (1970) Precipitation of kaolinite at 25°C and 1 atm: Clays & Clay Minerals 18, 261–267.CrossRefGoogle Scholar
  39. Kitterick, J. A. (1980) Gibbsite and kaolinite solubilities by immiscible displacement of equilibrium solutions: Soil Sci. Soc. Amer. J. 44, 139–142.CrossRefGoogle Scholar
  40. Kraus, I. (1968) Mineralogical-genetic study of clay sediments from the Poltar formation, southern Slovakia: Geol. Sbornik 19, 389–406.Google Scholar
  41. Kwong, K. F. N. K. and Huang, T. M. (1979) The relative influence of low-molecular-weight complexing organic acids on the hydrolysis and precipitation of aluminum: Soil Sci. 128, 337–342.CrossRefGoogle Scholar
  42. La Iglesia, A. and Galan, E. (1975) Halloysite-kaolinite transformation at room temperature: Clays & Clay Minerals 23, 109–113.CrossRefGoogle Scholar
  43. Lee, J. H. and Guggenheim, S. (1981) Single crystal X-ray refinement of pyrophyllite-1Tc: Amer. Mineral. 66, 350–357.Google Scholar
  44. Lind, C. J. and Hem, J. D. (1975) Chemistry of aluminum in natural water. Effects of organic solutes on chemical reactions of aluminum: U.S. Geol. Surv. Water-Supply Pap. 1827-G, 83 pp.Google Scholar
  45. Matushima, S., Kennedy, G. C., Akella, J., and Haygarth, J. (1967) A study of the equilibrium relations in the systems Al2O3-SiO2-H2O and Al2O3-H2O: Amer. J. Sci. 265, 28–44.CrossRefGoogle Scholar
  46. May, H. M., Helmke, P. A., and Jackson, M. L. (1979) Gibbsite solubility and thermodynamic properties of hydoxy-aluminum ions in aqueous solutions at 25°C: Geochim. Cosmochim. Acta 43, 861–868.CrossRefGoogle Scholar
  47. Mitsuhashi, T. and Kleppa, O. J. (1979) Transformation enthalpies of the titanium dioxide polymorphs: J. Amer. Ceram. Soc. 62, 356–357.CrossRefGoogle Scholar
  48. Neuhaus, A. and Heide, H. (1965) Hydrothermaluntersuchungen im System Al2O3-H2O(1): Zustansgrebzen und Stabilitätsverhahnisse vom Böhmit, Diaspor, und Korund im Drückbereich >50 bar: Deut. Ker. Gesell. Fachausschussbericht 42, 167–181.Google Scholar
  49. Parks, G. A. (1972) Free energies of formation and aqueous solubilities of aluminum hydroxides and oxide hydroxides at 25°C: Amer. Mineral. 57, 1163–1189.Google Scholar
  50. Perkins, D. P., III, Essene, E. J., Westrum, E. F., Jr., and Wall, V.J. (1979) New thermodynamic data for diaspore and their application to the system Al2O3-SiO2-H2O: Amer. Mineral. 64, 1080–1090.Google Scholar
  51. Perkins, D., Essene, E. J., and Wall V. J. (1987) THERMO: A computer program for calculation of mixed-volatile equilibria: Amer. Mineral. 72, 446–447.Google Scholar
  52. Polzer, W. L. and Hem, J. D. (1965) The dissolution of kaolinite: J. Geophys. Res. 70, 6233–6240.CrossRefGoogle Scholar
  53. Reed, B. L. and Hemley, J. J. (1966) Occurrence of py-rophyllite in the Kekiktuk Conglomerate, Brooks Range, northeastern Alaska: U.S. Geol. Surv. Prof. Pap. 550C, 162–166.Google Scholar
  54. Robie, R. A. and Hemingway, B. S. (1973) The enthalpies of formation of nesquehonite, MgCO3 · 3H2O, and hydromagnesite, 5MgO · 4CO2 · 5H2O: U.S. Geol. Surv. J. Res. 1, 543–547.Google Scholar
  55. Robie, R. A., Hemingway, B. S., and Fisher, J. R. (1979) Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (105 Pascals) pressure and at higher temperatures: U.S. Geol. Surv. Bull. 1452, 456 pp.Google Scholar
  56. Robie, R. A. and Hemingway, B. S. (1984) Entropies of kyanite, andalusite, and sillimanite: Additional constraints on the pressure and temperature of the Al2SiO5 triple point: Amer. Mineral. 69, 298–306.Google Scholar
  57. Robinson, G. R., Haas, J. L., Jr., Schafer, C. M., and Haselton, H. T. (1982) Thermodynamic and thermophysical properties of selected phases in the MgO-SiO2-H2O-CO2, CaO-Al2O3-SiO2-H2O-CO2, and Fe-FeO-Fe2O3-SiO2 chemical systems, with special emphasis on the properties of basalts and their mineral components: U.S. Geol. Surv. Open-File Rept. 83-79, 429 pp.Google Scholar
  58. Ross, G.J. and Turner, R.C. (1971) Effect of different anions on the crystallization of aluminum hydroxide in partially neutralized aqueous aluminum salt systems: Soil Sci. Soc. Amer. Proc. 35, 389–392.CrossRefGoogle Scholar
  59. Rothbauer, R., Zigan, F., and O’Daniel, H. (1967) Refinement of the structure of bayerite, Al(OH)3. Proposed positions of hydrogen atoms: Z. Kristallogr. 125, 317–331.CrossRefGoogle Scholar
  60. Russell, A. S., Edwards, J. D., and Taylor, C. S. (1955) Solubility of hydrated aluminas in NaOH solutions: Amer. Inst. MiningMetal. Eng. Trans., J. Metals 203, 1123–1128.Google Scholar
  61. Schoen, R. and Roberson, C. E. (1970) Structures of aluminum hydroxide and geochemical implications: Amer. Mineral. 55, 43–77.Google Scholar
  62. Shah, S. H.A. (1976) The laterite band of Siarat, Sibi, and Loralai districts, Baluchistan, Pakistan: Rec. Geol. Surv. Pakistan 37, 15–26.Google Scholar
  63. Slaughter, J., Wall, V. J., and Kerrick, D. M. (1976) APL computer programs for thermodynamic calculations of equilibria in P-T-XCO2 space: Contrib. Mineral. Petrol. 54, 157–171.CrossRefGoogle Scholar
  64. Smith, R. W. and Hem, J. D. (1972) Effect of aging on aluminum hydroxide complexes in dilute aqueous solutions: U.S. Geol. Surv. Water Supply Pap. 1827-D, 51 pp.Google Scholar
  65. Taylor, L. A. and Bell, P. M. (1969) Thermal expansion of pyrophyllite: Ann. Rep. Geophys. Lab., Carnegie Inst., Washington, D.C. 69, 193–194.Google Scholar
  66. Thompson, A. B. (1970) A note on the kaolinite-pyrophyllite equilibrium: Amer. J. Sci. 268, 454–458.CrossRefGoogle Scholar
  67. Tsuzuki, Y. and Kawabe, I. (1983) Polymorphic transformations of kaolin minerals in aqueous solutions: Geochim. Cosmochim. Acta 47, 59–66.CrossRefGoogle Scholar
  68. Turner, R. C. and Ross, G. J. (1970) Conditions in solution during the formation of gibbsite in dilute Al salt solutions. 4. Effect of Cl concentration and temperature and a proposed mechanism for gibbsite formation: Can. J. Chem. 48, 723–729.CrossRefGoogle Scholar
  69. Vaidya, S. N., Bailey, S., Pasternack, T., and Kennedy, G. C. (1973) Compressibility of fifteen minerals to 45 kilobars: J. Geophys. Res. 78, 6893–6898.CrossRefGoogle Scholar
  70. Velde, B. and Kornprobst, J. (1969) Stabilité, des silicates d’alumine hydrates: Contrib. Mineral. Petrol. 21, 63–74.CrossRefGoogle Scholar
  71. Violante, A. and Violante, P. (1980) Influence of pH, concentration, and chelating power of organic anions on the synthesis of aluminum hydroxides and oxyhydroxides: Clays & Clay Minerals 28, 425–435.CrossRefGoogle Scholar
  72. Volochaev, F. Ya., Kud’yarov, I. S., and Petrenko, V. I. (1978) Minerals of the upper Devonian Laterite weathering crust of the middle Timan: in Metallog. Osad. i Osadoch.-Metamorf. Tolshch, V. K. Chaikovskii, ed., 69–74 (Chem. Abst. 91: 60368).Google Scholar
  73. Wilson, M. D. and Pittman, E. D. (1977) Authigenic clays in sandstones: recognition and influence on reservoir properties and paleoenvironmental analysis: J. Sed. Petrol. 47, 3–31.Google Scholar
  74. Winter, J. K. and Ghose, S. (1979) Thermal expansion and high-temperature crystal chemistry of Al2SiO5 polymorphs: Amer. Mineral. 64, 573–586.Google Scholar
  75. Zen, E-a. (1961) Mineralogy and petrology of the system Al2O3-SiO2-H2O in some pyrophyllite deposits of North Carolina: Amer. Mineral. 46, 52–66.Google Scholar

Copyright information

© The Clay Minerals Society 1991

Authors and Affiliations

  • Lawrence M. Anovitz
    • 1
  • Dexter Perkins
    • 2
  • Eric J. Essene
    • 3
  1. 1.Department of GeosciencesThe University of ArizonaTucsonUSA
  2. 2.Department of Geology and Geological Engineering and the North Dakota Mining and Mineral Resources Research InstituteThe University of North DakotaGrand ForksUSA
  3. 3.Department of Geological SciencesThe University of MichiganAnn ArborUSA

Personalised recommendations