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Hot on the trail of mantle

28 June 2007

Scientists have found a way to track the path of mantle flowing beneath the Earth's continents. Their research, published in the journal Nature today, provides new insights into how some chains of submarine volcanic islands are formed.

Professor John Ludden, Director of the British Geological Survey and an author of the research paper, explains, "A stream of hot mantle rising below Africa can be traced as it flows beneath the continents and emerges to form volcanic ridges and new islands in the Atlantic and Indian oceans.  By measuring the isotopes* in the basalt rock we are able to tell where the mantle has come from, and what it has encountered along its journey to the surface of the Earth's crust."

As the molten mantle flows its progress is slowed by the vast land-masses protruding downwards, making the volcanic formations in these oceans more localised than in the Pacific, where the mantle flow is less constrained by large continents.

This gives a much more dynamic view of processes in the deep-Earth and provides important clues as to the shapes and the roles of the deep continental roots, some as deep as 200 kilometres, in controlling the flux of heat out of the earth. It could also help to pinpoint how and where diamonds are created in the depths of the Earth.

* Atoms with different numbers of neutrons in their nuclei, which therefore have different masses.

Further information

NERC Press Office
Natural Environment Research Council
Polaris House, North Star Avenue
Swindon, SN2 1EU
Tel: 01793 411561
Mob: 07917 557215

Notes

1. The full paper "Isotopic portrayal of the Earth's upper mantle flow field" is published in Nature 28 June 2007.

2. The authors are:

Christine M Meyzen, Janne Blichert-Toft and Francis Albarède, Laboratoire des Sciences de la Terre, CNRS UMR 5570, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364 Lyon cedex 07, France.

John N Ludden, British Geological Survey, Keyworth, NG12 5GG, Nottingham, UK.

Eric Humler, Laboratoire de Planétologie et Géodynamique, CNRS UMR 6112, Université de Nantes, 2 rue de la Houssinière, B.P. 92208, 44322 Nantes cedex 03, France.

Catherine Mével, Laboratoire de Géosciences Marines, CNRS UMR 7154, Institut de Physique du Globe, 4 place Jussieu, 75252 Paris cedex 05, France.

3. Copies of the paper can be obtained from the Natural Environment Research Council press office.

Press release: 23/07

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