Rapid Kimberlite Ascent and the Significance of Ar-Ar Ages in Xenolith Phlogopites

See allHide authors and affiliations

Science  28 Jul 2000:
Vol. 289, Issue 5479, pp. 609-611
DOI: 10.1126/science.289.5479.609

You are currently viewing the abstract.

View Full Text


Kimberlite eruptions bring exotic rock fragments and minerals, including diamonds, from deep within the mantle up to the surface. Such fragments are rapidly absorbed into the kimberlite magma so their appearance at the surface implies rapid transport from depth. High spatial resolution Ar-Ar age data on phlogopite grains in xenoliths from Malaita in the Solomon Islands, southwest Pacific, and Elovy Island in the Kola Peninsula, Russia, indicate transport times of hours to days depending upon the magma temperature. In addition, the data show that the phlogopite grains preserve Ar-Ar ages recorded at high temperature in the mantle, 700°C above the conventional closure temperature.

  • * To whom correspondence should be addressed. E-mail: s.p.kelley{at}

View Full Text