M.N. Taran, SYNTHETIC CO-EXISTING WADSLEYITE β-(Mg,Fe)2SiO4 AND RINGWOODITE γ-(Mg,Fe)2SiO4: AN OPTICAL ABSORPTION SPECTROSCOPY STUDY

https://doi.org/10.15407/mineraljournal.43.04.003

UDC 549.08

SYNTHETIC CO-EXISTING WADSLEYITE β-(Mg,Fe)2SiO4 AND RINGWOODITE γ-(Mg,Fe)2SiO4: AN OPTICAL ABSORPTION SPECTROSCOPY STUDY

M.N. Taran, DrSc (Geology, Mineralogy), Senior Research Fellow, Head of Department

M.P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of the NAS of Ukraine

34, Acad. Palladin Ave., Kyiv, Ukraine, 03142

E-mail: m_taran@hotmail.com; orcid: 0000-0001-7757-8829

Language: English

Mineralogical journal 2021, 43 (4): 03-10

Abstract: The synthetic high-pressure α- and β-modification of (Mg1–xFex)2SiO4, wadsleyite and ringwoodite, respectively, were studied by optical absorption spectroscopy at ambient and hydrostatic high-pressure conditions. In addition, the effects of thermal annealing on the crystals were investigated. Under hydrostatic compression up to ~13 GPa and then consequent released to atmospheric pressure there were changes in the spectra and related changes in the crystal color. This is a clear indication that some Fe2+ was oxidized to Fe3+. The spectra of both ringwoodite and wadsleyite change after annealing in air at temperatures up to 300 °C. The intensities of electronic spin-allowed bands of Fe2+ decrease and the intensity of the charge-transfer electronic transition O2– → Fe3+, as given by the low-energy absorption edge in the UV region, increases. These crystal-chemical changes are shown by a weakening of the blue (ringwoodite) and green (wadsleyite) colors and a concomitant increase in yellowish tints. The effects of Fe2+ oxidation to Fe3+, upon decompression from high pressures as well as through annealing at relatively low temperatures, can cause the disintegration of both phases. Thus, both minerals have not yet been reliably identified at near surface Earth conditions after originating from deep-seated volcanism or deep subduction zone processes.

Keywords: ringwoodite, wadsleyite, optical absorption spectra, influence of temperature and pressure.

References:

  1. Burns, R.G. (1993), Mineralogical Applications of Crystal Field Theory, 2nd ed., Cambridge Univ. Press, Cambridge, 576 p. https://doi.org/10.1017/CBO9780511524899
  2. Cox, P.A. (1980), Chem. Phys. Letters, Vol. 69, No. 2, pp. 340-343. https://doi.org/10.1016/0009-2614(80)85076-7
  3. Deer, W.A., Howie, R.A. and Zussman, J. (1997), Rock forming minerals: orthosilicates, 2nd ed., Geological Society of London, London.
  4. Frank, C.W. and Drickamer, H.G. (1976), The Physics and Chemistry of Minerals and Rocks, in Strens, R.G.J. (ed.), Wiley, New York, pp. 509-544.
  5. Girerd, J.J. (1983), J. Chem. Phys., Vol. 79, No. 4, pp. 1766-1775. https://doi.org/10.1063/1.446021
  6. Glazovskaya, L.I. and Feldman, V.I. (2012), Petrology, Vol. 20, No. 5, pp. 415-426. https://doi.org/10.1134/S0869591112050049
  7. Griffin, W.L., Afonso, J.C., Belousova, E.A., Gain, S.E., Gong, X.-H., González-Jiménez, J.M., Howell, D., Huang, J.-X., McGowan, N., Pearson, N.J., Satsukawa, T., Shi, R., Williams, P., Xiong, Q., Yang, J.-S., Zhang, M. and O’Reilly, S. (2016), J. Petrol., Vol. 57, No. 4, pp. 655-684. https://doi.org/10.1093/petrology/egw011
  8. Keppler, H. and Smyth, R.J. (2005), Amer. Mineral., Vol. 90, No. 7, pp. 1209-1212. https://doi.org/10.2138/am.2005.1908
  9. Khomenko, V.M. and Platonov, A.N. (1996), Phys. Chem. Minerals, Vol. 23, No. 4, pp. 243. https://doi.org/10.1007/BF00207761
  10. Mattson, S.M. and Rossman, G.R. (1987), Phys. Chem. Minerals, Vol. 14, No. 1, pp. 94-99. https://doi.org/10.1007/BF00311152
  11. Mrosko, M., Lenz, S., McCammon, C.A., Taran, M., Wirth, R. and Koch-Müller, M. (2013), Amer. Mineral., Vol. 98, No. 4, pp. 629-636. https://doi.org/10.2138/am.2013.4245
  12. Núñez-Valdez, M., da Silveira, P. and Wentzcovitch, R.M. (2011), J. Geophys. Res., Vol. 116, No. B12, p. B12207. https://doi.org/10.1029/2011JB008378
  13. Pearson, D.G., Brenker, F.E., Nestola, F., McNeill, J., Nasdala, L., Hutchison, M.T., Matveev, S., Mather, K., Silversmit, G., Schmitz, S., Vekemans, B. and Vincze, L. (2014), Nature, Vol. 507, pp. 221-224. https://doi.org/10.1038/nature13080
  14. Sherman, D.M. (1987), Phys. Chem. Minerals, Vol. 14, No. 4, pp. 355-363. https://doi.org/10.1007/BF00309810
  15. Smith, G. (1977), Canad. Mineral., Vol. 15, No. 4, pp. 500-507.
  16. Smith, G. and Strens, R.G.J. (1976), The Physics and Chemistry of Minerals and Rocks, in Strens, R.G.J. (ed.), Wiley, New York, pp. 583-612.
  17. Smyth, J.R., Holl, C.M., Langenhorst, F., Laustsen, H.M.S., Rossman, G.R., Kleppe, A., McCammon, C.A., Kawamoto, T. and van Aken, P.A. (2005), Phys. Chem. Minerals, Vol. 31, No. 10, pp. 691-705. https://doi.org/10.1007/s00269-004-0431-x
  18. Sobolev, N.V., Logvinova, A.M., Zedgenizov, D.A., Pokhilenko, N.P., Kuzmin, D.V. and Sobolev, A. (2008), Eur. J. Miner., Vol. 20, No. 3, pp. 305-315. https://doi.org/10.1127/0935-1221/2008/0020-1829
  19. Taran, M.M. (2020), Optical spectroscopy of ions of transition metals of minerals at different temperatures and pressures: spectroscopic, crystal chemical and thermodynamic aspects, Nauk. dumka, Kyiv, UA, 400 p. [in Ukrainian].
  20. Taran, M.N. and Koch-Müller, M. (2012), 14th Int. Conf. Experimental Mineralogy, Petrology, Geochemistry EMPG, 03-06.03.2012, Kiel, Germany, Abstracts, p. 136.
  21. Taran, M.N., Koch-Müller, M., Wirth, R., Abs-Wurmbach, I., Rhede, D. and Greshake, A. (2009), Phys. Chem. Minerals, Vol. 36, No. 4, pp. 217-232. https://doi.org/10.1007/s00269-008-0271-1
  22. Taran, M.N. and Langer, K. (1998), Neues Jb. Miner. Abh., Band 172, Heft 2-3, pp. 325-346. https://doi.org/10.1127/njma/172/1998/325
  23. Taran, M.N., Langer, K. and Platonov, A.N. (1996), Phys. Chem. Minerals, Vol. 23, No. 4-5, pp. 230-236. https://doi.org/10.1007/BF00207754
  24. Taran, M.N., Ohashi, H. and Koch-Müller, M. (2008), Phys. Chem. Minerals, Vol. 35, No. 3, pp. 117-127. https://doi.org/10.1007/s00269-007-0202-6
  25. Thomas, S.-M., Bina, C.R., Jacobsen, S.D. and Goncharov, A.F. (2012), Earth and Planet. Sci. Lett., Vol. 357-358, No. 1, pp. 130-136. https://doi.org/10.1016/j.epsl.2012.09.035
  26. Wong, K.Y., Schatz, P.N. and Piepo, S.B. (1979), J. Amer. Chem. Soc., Vol. 101, No. 11, pp. 2793-2803. https://doi.org/10.1021/ja00505a001

PDF

English