06 September 2002
Vol 297, Issue 5587

About The Cover

Cover image expansion

COVER An eclogite from the Roberts Victor Mine, South Africa. These rocks are thought to be pieces of ocean floor thrust into the mantle keel of the Kaapvaal Craton during its stabilization 2.9 billion years ago. This process resulted in widespread diamond genesis. Reddish grains are garnet; others are pyroxene. Kidney-shaped garnet (center) is 4 mm across. 1683 [Specimen: J. J. Gurney, University of Cape Town; image: S. B. Shirey]