Antonangeli D., Morard G., Schmerr N. C., Komabayashi T., Krisch M., Fiquet Guillaume, Fei Y. W. (2015). Toward a mineral physics reference model for the Moon's core. Proceedings of the National Academy of Sciences of the United States of America, 112 (13), p. 3916-3919. ISSN 0027-8424.
Titre du document
Toward a mineral physics reference model for the Moon's core
Antonangeli D., Morard G., Schmerr N. C., Komabayashi T., Krisch M., Fiquet Guillaume, Fei Y. W.
Source
Proceedings of the National Academy of Sciences of the United States of America, 2015,
112 (13), p. 3916-3919 ISSN 0027-8424
The physical properties of iron (Fe) at high pressure and high temperature are crucial for understanding the chemical composition, evolution, and dynamics of planetary interiors. Indeed, the inner structures of the telluric planets all share a similar layered nature: a central metallic core composed mostly of iron, surrounded by a silicate mantle, and a thin, chemically differentiated crust. To date, most studies of iron have focused on the hexagonal closed packed (hcp, or epsilon) phase, as epsilon-Fe is likely stable across the pressure and temperature conditions of Earth's core. However, at the more moderate pressures characteristic of the cores of smaller planetary bodies, such as the Moon, Mercury, or Mars, iron takes on a face-centered cubic (fcc, or gamma) structure. Here we present compressional and shear wave sound velocity and density measurements of gamma-Fe at high pressures and high temperatures, which are needed to develop accurate seismic models of planetary interiors. Our results indicate that the seismic velocities proposed for the Moon's inner core by a recent reanalysis of Apollo seismic data are well below those of gamma-Fe. Our dataset thus provides strong constraints to seismic models of the lunar core and cores of small telluric planets. This allows us to propose a direct compositional and velocity model for the Moon's core.
Plan de classement
Sciences de la Terre : généralités [060]
;
Géophysique interne [066]
