Polymict Peridotites from the Bultfontein and de Beers Mines, Kimberly, South Africa

  1. F.R. Boyd and
  2. Henry O.A. Meyer
  1. P.J. Lawless1,
  2. J.J. Gurney2 and
  3. J.B. Dawson3

Published Online: 19 MAR 2013

DOI: 10.1029/SP016p0145

The Mantle Sample: Inclusion in Kimberlites and Other Volcanics

The Mantle Sample: Inclusion in Kimberlites and Other Volcanics

How to Cite

Lawless, P.J., Gurney, J.J. and Dawson, J.B. (1979) Polymict Peridotites from the Bultfontein and de Beers Mines, Kimberly, South Africa, in The Mantle Sample: Inclusion in Kimberlites and Other Volcanics (eds F.R. Boyd and H. O.A. Meyer), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP016p0145

Author Information

  1. 1

    Anglo American Research Laboratory, P.O. Box 106, Crown Mines, Transvaal, 2025, South Africa

  2. 2

    Department of Geochemistry, University of Cape Town, Private Bag, Rondebosch, 7700 Cape, South Africa

  3. 3

    Department of Geology, Purdie Building, University of St. Andrews Fife, Scotland KY 16 9 St. United Kingdom

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1979

ISBN Information

Print ISBN: 9780875902135

Online ISBN: 9781118664858

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Keywords:

  • Chromite;
  • Clinopyroxene megacrysts;
  • Polymict peridotites;
  • Rock clasts;
  • Xenocrystic minerals

Summary

Four samples of hitherto undescribed xenoliths from the Bultfontein and De Beers kimberlites have been studied. The rocks consist of a wide variety of peridotitic xenoliths, eclogite fragments and megacryst minerals cemented together by ilmenite, phlogopite, rutile and sulphides. The rocks have been called polymict peridotites. They are interpreted as remnant conduit filling left behind in the mantle after the migration of a kimberlitic fluid upwards. Subsequent to consolidation the polymict rocks were sampled by one of the Bultfontein kimberlite intrusions.

A zircon age of 82.8 m.y. is thought to apply to the sampling event.