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Strong premelting effect in the elastic properties of hcp-Fe under inner-core conditions.(REPORTS)(Report)(Author abstract)

Martorell, Benjami ; Vocadlo, Lidunka ; Brodholt, John ; Wood, Ian G.

Science, Oct 25, 2013, Vol.342(6157), p.466(3) [Periódico revisado por pares]

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  • Título:
    Strong premelting effect in the elastic properties of hcp-Fe under inner-core conditions.(REPORTS)(Report)(Author abstract)
  • Autor: Martorell, Benjami ; Vocadlo, Lidunka ; Brodholt, John ; Wood, Ian G.
  • Assuntos: Elasticity (Mechanics) -- Research ; Shear (Mechanics) -- Research ; Iron (Metal) -- Mechanical Properties
  • É parte de: Science, Oct 25, 2013, Vol.342(6157), p.466(3)
  • Descrição: The observed shear-wave velocity [V.sub.s] in Earth's core is much lower than expected from mineralogical models derived from both calculations and experiments. A number of explanations have been proposed, but none sufficiently explain the seismological observations. Using ab initio molecular dynamics simulations, we obtained the elastic properties of hexagonal close-packed iron (hcp-Fe) at 360 gigapascals up to its melting temperature [T.sub.m]. We found that Fe shows a strong nonlinear shear weakening just before melting (when T/[T.sub.m] > 0.96), with a corresponding reduction in [V.sub.s]. Because temperatures range from T/[T.sub.m] = 1 at the inner-outer core boundary to T/[T.sub.m] [approximately equal to] 0.99 at the center, this strong nonlinear effect on [V.sub.s] should occur in the inner core, providing a compelling explanation for the low [V.sub.s] observed. 10.1126/science.1243651
  • Idioma: English

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