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Published July 1984 | public
Journal Article

Minor elements in perovskite from kimberlites and distribution of the rare earth elements: An electron probe study

Abstract

We report REE and minor element distributions for perovskites from seven kimberlites (South Africa and U.S.A.). The REE (1.6–6.3 oxides wt.%) are always strongly light REE enriched, often with Ce > La (chondrite-normalized), and show an expected close correlation with whole-rock analyses. Where examined, perovskite contains far more REE than coexisting apatite, by about an order of magnitude. Calculations indicate that iron is mostly present as Fe^(3+) and is low (1.0–2.9 wt.% Fe_2O_3) compared with perovskite from carbonatite complexes such as Oka (4.4 wt.% FeO [3]). In addition to established Nb (0.3–1.7 oxide wt.%), geochemically interesting elements encountered include Zr (up to 1.5 oxide wt.%), Ba and Sr (up to 0.2, 0.4 oxide wt.% respectively). Specific geological applications suggest a possible genetic link between Wesselton pipe and Benfontein Sills kimberlites, and that carbonate-rich dikes in the Premier mine were derived from kimberlites. The overall similarities with incompatible element-rich titanates in veined mantle peridotites suggest a more direct link between kimberlite magmatism and mantle metasomatism.

Additional Information

© 1984 Elsevier Science Publishers B.V. Received January 4, 1984; Revised version received March 7, 1984. This research was supported by the Earth Science Division of the National Science Foundation, grants EAR 81-08599 and EAR 83-11758. All material from South Africa was collected by P.J. Wyllie during the First International Kimberlite Conference, 1973, thanks to J.B. Hawthorne of the De Beers Mining Corporation. The two kimberlite samples from the United States were kindly furnished by D. Schulze. R.A. Exley provided useful advice about the electron probe REE method at the University of Chicago, and together with I.M. Steele and A.M. Davis is thanked for helpful discussion. We thank H.O.A. Meyer for a constructive review. Contribution No. 4046, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California.

Additional details

Created:
August 22, 2023
Modified:
October 17, 2023