Thermodynamic Evaluation of Fe Effect on Alumina Solubility in Orthopyroxene coexisting with Garnet

  • Lee, Han-Yeang (Korea Institute of Geosciences and Mineral Resources (KIGAM))
  • 발행 : 2004.01.31

초록

In the FMAS system the effect of iron on alumina solubility in orthopyroxene has been determined by experiments with crystalline starting mixtures of garnet and orthopyroxene of known initial compositions at 20 kb, 975$^{\circ}C$ and 25 kb, 1,200$^{\circ}C$. These data have been modeled to develop a thermodynamic method for the calculation of Al$_{2}$O$_{3}$ in orthopyroxene as a function of P, T and composition. The direct application of the alumina solubility data in the MAS system to natural assemblages could lead to significant overestimation of pressure, probably by about 5kb for the relatively common garnet-lherzolites with abot 25 mol per cent Ca + Fe$^{2+}$ in garnet and about 1 wt. per cent Al$_{2}$O$_{3}$ in orthopyroxene since the effect of Fe is similar to that of Ca and Cr$^{3+}$in reducing the alumina solubility in orthopyroxene in equilibrum with garnet relative to that in the MAS system.

키워드

참고문헌

  1. AkeIla, J., 1976, Garnet-pyroxene equilbria in the system $CaSiO_8-MgSio_3-Al_2O_3$and in a natural mineral mixture. American Mineralogist. 61, 589-598
  2. Bertrand, P., Sotin, C., Mercier, J.C.C., and Takahashi, E., 1986. From the simplest chemical system to the natural one: garnet peridotite barometry. Contribution to mineralogy and Petrology. 93, 168-178 https://doi.org/10.1007/BF00371318
  3. Boyd, F.R and England, J.L., 1964, The system of enstatite-pyrope. Carnegie Institute of Washington, Yearbook, 63, 157-161
  4. Chatillon-Colinet, C., Newtoon, R.C., Perkins, D., and Kleppa, O.J., 1983b. Thermochemistry of $(Fe^2^+,Mg)SiO_3$ orthopyroxene. Geochim. Cosmochim. Acta, 47, 1597-1603 https://doi.org/10.1016/0016-7037(83)90186-2
  5. Chatterjee, N.D. and Terhart, L., 1985, Thermodynamic claculation of peridoitite phase relations in the system $MgO-Al_2O_3-SiO_2-Cr_2O_3$ sith some gelolgical applications. Contributions to Mineralogy and Petrology, 89, 273-284 https://doi.org/10.1007/BF00379460
  6. Danckwerth, P.A and Newton, R.C., 1978, Experimental detenmination of the spinel peridotite to garnet peridotite reaction in the system TEX>$$MgO-Al_2O_3-SiO_2$$ in the range 900-11OO°C and $Al_2O_3$ isopleths of enstatite in the spinel field. Contributions to Mineralogy and Petrology, 66, 189-201 https://doi.org/10.1007/BF00372158
  7. Finnerty, A.A .and Boyd, F.R., 1984, Evaluation of thermobarometer for garnet peridotites. Geochim. Cosmochim. Acta, 48, 15-27 https://doi.org/10.1016/0016-7037(84)90346-6
  8. Ganguly, J. and kennedy, C.C, 1974, The energetic of natural garnet solid solution l. Mixing of the alumino-slicate end memvers. Contributions to Mineralogy and Petrology, 48, 137-148 https://doi.org/10.1007/BF00418615
  9. Ganguly, J. and Ghose, S., 1979, Aluminuous orthopyroxene: order-disorder, thenmodynamic properties, and pertologic implications. Contributions to Mineralogy and Petrology, 69, 375-385 https://doi.org/10.1007/BF00372263
  10. Ganguly, J. and saxena, S.K., 1987, Mixtures and mineral reactions. New York, Berlin, Heidelverg: Springer-Ver lag
  11. Ganguly, J. and Bhattacharya, P.K., 1987, Xenolith in Proterozoic Kimverites from southern India: Petrology and geophysical implications. In: Nixon, P. H. (Ed.) Mantle Xenoliths. New York: John Wiley and sons, 249-265
  12. Gasparik, T. and Newton, R.C.,1984, The reversed alumina contents of orthopyroxene in equilibirum with spinel and forsterite in the system $MgO-Al_2O_3-SiO_2$. Contributions to Mineralogy and Petrology, 86, 186-196
  13. Harley, S.L., 1984, An experimintal study of the partitioning of Fe and Mg between gamet and ortyopyroxene. Contributions to Mineralogy and Petrology, 86, 359-373 https://doi.org/10.1007/BF01187140
  14. Howells, S. and O'Hara, J.J., 1978, Low solubility of alumina in enstatite and uncertainties in estimated paleogeotherms. Philosophy of Transactions of Royal Society of London, A-288, 471-486
  15. Jenkins, D.M. and Newton, R.C., 1979, Experimental determination to the spinel peridotite to gamet perdotite inversion at 900C and l000°C in the system $CaO-MgO-AI_2O_3-SiO_2$, and at 900$^{\circ}C$ with natural gamet and olivine. Contributions to Mineralogy and Petrology, 68, 407-419 https://doi.org/10.1007/BF01164525
  16. Kawasaki, T. and Matsui, Y., 1983, Thermidynarnic analysis of equilibria involving olivine, orthopyroxene and grnet, Geochim. cosmichim. Acta. 47, 1661-1679 https://doi.org/10.1016/0016-7037(83)90017-0
  17. Lane, D.L. and ganguly, J., 1980,$$AI_2O_3 $$solubility in orthopyroxene in the system $MgO-AI_2O_3-SiO_3 $: A reevaluation, and mantle geotherm. Journal of Geophysical Research, 86, 6963-6972
  18. Lee, H.Y., 1988, Gamet-orthopyroxene geothermometer and geological applications. Journal of Korean Institute of Mining Geology, 21, 29-44
  19. MacGregor, I.D., 1974, The system$MgO-AI_2O_3-SiO_3$: Solubility of$AI_2O_3$in enstatite for spinel and gamet peridotite compositions. American Mineralogist, 59, 110-119
  20. Mori, T. and Green, D.H., 1978, Laboratioy duplication of phase equilibria observed in natural gamet-Iherzo-lite. Journal of Geology, 86, 83-97 https://doi.org/10.1086/649657
  21. Obata, M, 1976, The solubility of $AI_2O_3$in orthopyroxenes in spinel and plagioclase peridotites and spinelpryoxene. American Mineralogist, 61, 804-816
  22. Perkins, D., and Newton, R.C., 1980, The compositions of coexisting pyroxenes and gamet in the system $$CaO-MgO-AI_2O_3-SiO_2 $$ at 9OO-1100$^{\circ}C $ and high pressures.Contributions to Mineralogy and Petrology, 75, 291-300
  23. Perkins, D., Holland, TJ.B., and Newton, T.C, 1981,$AI_2O_3$ contents of enstatite in equilivrium with gamet in the system $MgO-AI_2O_3-SiO_2 $at 15-49kb and 9001600°e. Contributions to Mineralogy and Petrology, 78, 99-109 https://doi.org/10.1007/BF00371147
  24. Wood, B.J. and Banno, S., 1973, Garnet-orthopyroxene and orthopyroxene-clinopyroxene relationships in simple and complex systems. Contributions to Mineralogy and Petrology, 42, 109-124 https://doi.org/10.1007/BF00371501
  25. Wood, B.J., 1974, The solubility of alumina in orthopyroxene coexisting with gamet. Contributions to Mineralogy and Petrology, 46, 1-15 https://doi.org/10.1007/BF00377989