Density deficit of the Earth's core revealed by a multi-megabar primary pressure scale

Fuente: arXiv
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Bibliographic Details
Main Authors: Ikuta, Daijo, Ohtani, Eiji, Fukui, Hiroshi, Sakamaki, Tatsuya, Heid, Rolf, Ishikawa, Daisuke, Baron, Alfred Q. R.
Format: Preprint
Published: 2021
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author Ikuta, Daijo
Ohtani, Eiji
Fukui, Hiroshi
Sakamaki, Tatsuya
Heid, Rolf
Ishikawa, Daisuke
Baron, Alfred Q. R.
author_facet Ikuta, Daijo
Ohtani, Eiji
Fukui, Hiroshi
Sakamaki, Tatsuya
Heid, Rolf
Ishikawa, Daisuke
Baron, Alfred Q. R.
contents An accurate pressure scale is a fundamental requirement to understand planetary interiors. Here, we establish a primary pressure scale extending to the multi-megabar pressures of the Earth's core, by combined measurement of the acoustic velocities and the density from a rhenium sample in a diamond anvil cell using inelastic x-ray scattering and x-ray diffraction. Our scale agrees well with previous primary scales and shock Hugoniots in each experimental pressure range, and reveals that previous scales have overestimated laboratory pressures by at least 20% at 230 gigapascals. It suggests that the light element content in the Earth's inner core (the density deficit relative to iron) is likely to be double what was previously estimated, or the Earth's inner core temperature is much higher than expected, or some combination thereof.
format Preprint
id arxiv_https___arxiv_org_abs_2104_02076
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Density deficit of the Earth's core revealed by a multi-megabar primary pressure scale
Ikuta, Daijo
Ohtani, Eiji
Fukui, Hiroshi
Sakamaki, Tatsuya
Heid, Rolf
Ishikawa, Daisuke
Baron, Alfred Q. R.
Geophysics
Earth and Planetary Astrophysics
An accurate pressure scale is a fundamental requirement to understand planetary interiors. Here, we establish a primary pressure scale extending to the multi-megabar pressures of the Earth's core, by combined measurement of the acoustic velocities and the density from a rhenium sample in a diamond anvil cell using inelastic x-ray scattering and x-ray diffraction. Our scale agrees well with previous primary scales and shock Hugoniots in each experimental pressure range, and reveals that previous scales have overestimated laboratory pressures by at least 20% at 230 gigapascals. It suggests that the light element content in the Earth's inner core (the density deficit relative to iron) is likely to be double what was previously estimated, or the Earth's inner core temperature is much higher than expected, or some combination thereof.
title Density deficit of the Earth's core revealed by a multi-megabar primary pressure scale
topic Geophysics
Earth and Planetary Astrophysics
url https://arxiv.org/abs/2104.02076