Personne

James Badro

Publications associées (36)

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Partitioning of Si and platinum group elements between liquid and solid Fe-Si alloys

James Badro

Crystallization of the Earth's inner core fractionates major and minor elements between the solid and liquid metal, leaving physical and geochemical imprints on the Earth's core. For example, the density jump observed at the Inner Core Boundary (ICB) is re ...

Pergamon-Elsevier Science Ltd2014

A seismologically consistent compositional model of Earth's core

James Badro

Earth's core is less dense than iron, and therefore it must contain "light elements," such as S, Si, O, or C. We use ab initio molecular dynamics to calculate the density and bulk sound velocity in liquid metal alloys at the pressure and temperature condit ...

Natl Acad Sciences2014

Silicon isotopes in angrites and volatile loss in planetesimals

James Badro

Inner solar system bodies, including the Earth, Moon, and asteroids, are depleted in volatile elements relative to chondrites. Hypotheses for this volatile element depletion include condensation from the solar nebula and volatile loss during energetic impa ...

Natl Acad Sciences2014

Spin Transitions in Mantle Minerals

James Badro

Mantle minerals at shallow depths contain iron in the high-spin electronic state. The crystal-field splitting energy increases with increasing pressure, which can favor the low-spin state. Hence, pressure-driven transitions from the high-spin to the low-sp ...

Annual Reviews2014

Terrestrial Accretion Under Oxidizing Conditions

James Badro

The abundance of siderophile elements in the mantle preserves the signature of core formation. On the basis of partitioning experiments at high pressure (35 to 74 gigapascals) and high temperature (3100 to 4400 kelvin), we demonstrate that depletions of sl ...

2013

Redox state during core formation on asteroid 4-Vesta

James Badro

Core formation is the main differentiation event in the history of a planet. However, the chemical composition of planetary cores and the physicochemical conditions prevailing during core formation remain poorly understood. The asteroid 4-Vesta is the smal ...

Elsevier2013

Deformation of (Mg-0.9,Fe-0.1)SiO3 Perovskite aggregates up to 32 GPa

Philippe Gillet, James Badro

Room temperature investigations on the shear stress and deformation mechanisms of (Mg0.9Fe0.1)SiO3 perovskite are performed in situ up to 32 GPa using radial X-ray diffraction and the diamond anvil cell as a deformation apparatus. The uniaxial stress suppo ...

2003

Melting and pressure-induced amorphization of quartz

Philippe Gillet, James Badro

It has recently been shown that amorphization and melting of ice (O. MISHIMA, Nature, 384 (1996) 546) were intimately linked. In this letter, we infer from molecular-dynamics simulations on the SiO2 system that the extension of the alpha-quartz melting lin ...

1998

Low argon solubility in silicate melts at high pressure

Philippe Gillet, James Badro

The solubility of rare gases in silicate melts and minerals at high pressure is of importance for understanding the early history of the Earth and its present day degassing. Helium, neon, argon, krypton and xenon were originally incorporated into the Earth ...

1998

Combined X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) experiments have been carried out on alpha-GaAsO4 (berlinite structure) at high pressure and room temperature. XAS measurements indicate four-fold to six-fold coordination changes for ...

1997