Geochemistry

Getting an Iron Grip

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Science  17 Mar 2000:
Vol. 287, Issue 5460, pp. 1889
DOI: 10.1126/science.287.5460.1889d

Earth's iron core creates our planet's magnetic field; the geodynamo is driven by convection in the liquid outer core that surrounds the solid inner core. The properties of iron at extreme pressures and temperatures, and particularly the structure of iron that is present in the core and its melting temperature, have been the focus of much study, as these data would limit the temperature of Earth's interior and would allow seismic observations of features in the core to be interpreted more reliably. Several papers in a special issue of American Mineralogist tackle these questions. In particular, Anderson and Isaak summarize some of the recent results (and debate) that surround the iron phase diagram, including the possible presence of a new fifth phase of iron that might be present at core conditions. They conclude that a fifth iron phase is likely but that its melting temperature is still uncertain.—BH

Am. Mineral.85, 376 (2000)

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