PerspectiveGeophysics

Are Earth's Core and Mantle on Speaking Terms?

Science  01 Oct 2004:
Vol. 306, Issue 5693, pp. 64-65
DOI: 10.1126/science.1102976

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Summary

The degree to which Earth's metallic core and silicate mantle interact at their interface has been difficult to constrain. In his Perspective, Lee discusses the report by Humayun et al., who show that hotspot magmas (whose mantle source regions are believed to derive from the lower mantle) have anomalously high Fe/Mn ratios compared to magmas that sample the upper mantle. The authors present this as evidence for a lower mantle enriched in iron, possibly as a consequence of long-term chemical interaction between the core and the mantle. However, alternative explanations for high Fe/Mn ratios in magmas remain possible.