New measurement of melting and thermal conductivity of iron close to outer core conditions

• Main Authors: Abhisek Basu, Matthew R. Field, Dougal G. McCulloch, Reinhard Boehler
• Format: Article
• Language: English
• Published: Elsevier 2020-03-01
• Series: Geoscience Frontiers
• Online Access: http://www.sciencedirect.com/science/article/pii/S1674987119301227

The amount of literature on both melting and thermal conductivity of iron at Earth’s core conditions is overwhelming and the discrepancies are very large. There is a broad range of experimental techniques each of which is flawed to a certain degree, which may explain the discrepancy. In this report, we present new data using a different method for determining the phase behavior and resistivity of iron in the laser-heated diamond cell by measuring the electrical resistance of both solid and liquid iron wires. The experiment avoids some of the major flaws of previous experiments, the most important of which is the detection of the onset of melting. These measurements confirm a shallow melting curve found earlier and the resistivity data imply a trend towards low thermal conductivity in the liquid outer core. Keywords: Outer core, Thermal conductivity, Iron phase diagram, Diamond anvil cell, High pressure