The Earth's core composition from high pressure density measurements of liquid iron alloys | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  The Earth's core composition from high pressure density measurements of liquid iron alloys

Type de publication:

Journal Article

Source:

Earth and Planetary Science Letters, Volume 373, p.169-178 (2013)

ISBN:

0012-821X

URL:

http://www.sciencedirect.com/science/article/pii/S0012821X13002355

Mots-clés:

UMR 7154 ; Géobiosphère actuelle et primitive ; Earth's core composition; high pressure; density; liquid iron alloys

Résumé:

High-pressure, high-temperature in situ X-ray diffraction has been measured in liquid iron alloys (Fe–5 wt% Ni–12 wt% S and Fe–5 wt% Ni–15 wt% Si) up to 94 GPa and 3200 K in laser-heated diamond anvil cells. From the analysis of the X-ray diffuse scattering signal of the metallic liquids, we determined density and bulk modulus of the two liquid alloys. Comparison with a reference Earth model indicates that a core composition containing 6% of sulfur and 2% of silicon by weight would best match the geophysical data. Models with 2.5% of sulfur and 4–5% of silicon are still consistent with geophysical constraints whereas silicon only compositions are not. These results suggest only moderate depletion of sulfur in the bulk Earth.

Notes:

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