Neodymium and Strontium Isotopic Measurements on Single Subcalcic Garnet Grains from Yakutian Kimberlites

D. E. Jacob*, E. Jagoutz, N. V. Sobolev

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Discrete grains of subcalcic garnets from Yakutian kimberlites have been investigated for major elements, Sm, Sr, Nd, Rb concentrations as well as for 87Sr/86Sr and 143Nd/144Nd ratios. εNdi-values range between +1 and -40.6, 87Sr/86Sr are between 0.70521 and 0.72632, confirming the very heterogeneous character of these minerals. Sm/Nd ratios range from 0.025 to 0.828. Strong positive correlations of 87Sr/86Sr-ratios with Cr and Mn are consistent with an origin of the subcalcic garnets from Cr-spinels from spinel-harzburgites which were subducted into depths of the diamond stability field and reacted there with a metasomatic agent producing subcalcic garnet and olivine at the expense of Cr-spinel, orthopyroxene and any remaining clinopyroxene. It is proposed that subcalcic garnets are formed episodically through time and that kimber-lites randomly sample populations of these minerals which are not necessarily cogenetic.

Original languageEnglish
Pages (from-to)357-379
Number of pages23
JournalNeues Jahrbuch fur Mineralogie, Abhandlungen
Volume172
Issue number2-3
Publication statusPublished - 1998
Externally publishedYes

Keywords

  • Nd/Nd
  • Sr/Sr
  • Diamond indicator
  • Spinel harzburgites
  • Subcalcic garnets
  • Trace elements

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