Temperature of the inner-core boundary of the Earth: Melting of iron at high pressure from first-principles coexistence simulations

By Dario Alfè. 2009

136 citations recorded by the source corpus.

The Earth's core consists of a solid ball with a radius of 1221 Km, surrounded by a liquid shell which extends up to 3480 km from the center of the planet, roughly half way toward the surface (the mean radius of the Earth is 6373 km). The main constituent of the core is iron, and therefore the melting temperature of iron at the pressure encountered at the boundary between the solid and the liquid [the inner-core boundary (ICB)] provides an estimate of the temperature of the core. Here I report the melting temperature of Fe at pressures near that of the ICB, obtained with first-principles techniques based on density-functional theory. The calculations have been performed by directly simulating solid and liquid iron in coexistence and show that and at a pressure of similar to 328 GPa iron melts at similar to 6370 +/- 100 K. These findings are in good agreement with earlier simulations, which used exactly the same quantum-mechanics techniques but obtained melting properties from the calculation of the free energies of solid and liquid Fe.

Subfields: Condensed Matter Physics, Geophysics

View Paper: https://www.semanticscholar.org/paper/e4a7b824cdef59ba3463fc234b8ec578fdba3fea

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Citations in the corpus

Solidus and liquidus profiles of chondritic mantle: Implication for melting of the Earth across its history (2011, background): “On the other hand, shock-wave experiments and ab-initio calculations suggest melting temperatures of more than 6000 K at 330 GPa (Alfe, 2009; Nguyen and Holmes, 2004).”
Thermal and electrical conductivity of solid iron and iron-silicon mixtures at Earth's core conditions (2013, methodology): “Here we compute the conductivities of pure solid iron at pressures close to that at the ICB, p = 329 GPa, and to the centre of the Earth, p = 364 GPa, at the DFT melting temperature of pure iron Tm = 6350 K (Alfè et al., 2002; Alfè, 2009; Anzellini et al., 2013).”