Abstract
Five ilmenite megacrysts from the Premier kimberlite pipe have been analysed by Mössbauer spectroscopic and electron microprobe techniques for their Fe3+/Fe2+ ratio; and by nuclear bombardment techniques for their N2 content. Comparison of the Fe3+/Fe2+ ratio determined from electron microprobe analysis for total Fe assuming stoichiometry with the direct determination of this ratio by Mössbauer techniques is sufficiently good that the former method which is very widely used may be considered reliable. The N2 content of the ilmenite samples ranges from 0.5 to 2.0%, considerably in excess of that for most minerals. Heating experiments suggest that the N2 is not located in liquid inclusions. Isotopic analysis of ilmenite is not available and so its origin is uncertain, but these results suggest that ilmenite could be a major reservoir for N2 in the earth's mantle.
Similar content being viewed by others
References
S.E. Haggerty and L.A. Tomkins, Nature 303 (1983) 295.
S.E. Haggerty, Geol. Soc. Australia, Special Pub., Blakwell Sci. Pub., Victoria, Australia 2, 1989 p. 356.
D. Virgo, R.W. Luth, M.A. Moats and G.C. Ulmer, Geochem. Cosmochim. Acta 52 (1988) 1781.
L.W. Luth, D. Virgo, F.R. Boyd and B.J. Wood, Contrib. Min. Petrol. 104 (1990) 56.
J.B.F. Sellschop, C.C.P. Madiba and H.J. Annergan, Nucl. Instr. Meth. 168 (1980) 529.
C.C.P. Madiba, Thesis (Univ. Witwatersand, Johannesburg, 1986).
R.V. Danchin, in: Proc. 2nd Inter. Kimberlite Conf., ed. F.R. Boyd, Am. Geophys. Union 2 (197) 104.
D.B. Apter, F.J. Wyatt and B.A. Smith, in: Kimberlites and Related Rocks, ed. Kornprost (Elsevier, 1984) p. 42.
G.R. Hearne, P.R. Stoddart and H. Pollak, Physica C 167 (1990) 415.
J.P.F. Sellschop, C.C.P. Madiba, H.J. Annegarn and A.H. Andeweg, Nucl. Instr. Meth. 218 (1983) 23.
C. Engelman, J. Radioanal. Chem. 7 (1971) 281.
H.J. Annegarn, R.J. Keddy and A.M.C. St Quintin, NPRU Report (Univ. Witwatersrand, Johannesburg, SA, 1978) p. 8.
F. James and M. Ross, Comput. Phys. Comm. 10 (1965) 343.
T. Andersen, E.A.J. Burke and H. Austrheim, Contrib. Min. Petrol. 103 (189) 153.
G.E. Bebout and Fogel, Annual Rep. Dir. Geophys. Lab. Carnegie Inst. (Washington, 1990) p. 19.
P.C. Ater, D.H. Eggler and M.E. McCallum, in: Kimberlites and Related Rocks, ed. Kornprost (Elsevier, 1984) p. 309.
G.E. Bebout and M.D. Barton, EOS Trans. Am. Geophys. Union 70 (1989) 1367.
J.J. Gurney, Geol. Soc. Australia, Special Pub., Blakwell Sci. Pub., Victoria, Australia 2, 1989 p. 687.
M. Javoy, F. Pineau and H. Delorme, Chem. Geol. 57 (1986) 41.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Madiba, C., Pollak, H., Cawthorn, R. et al. Ilmenite: mantle reservoir for nitrogen?. Hyperfine Interactions 111, 319–327 (1998). https://doi.org/10.1023/A:1012694809968
Issue Date:
DOI: https://doi.org/10.1023/A:1012694809968