Partitioning of potassium between iron and silicate at the core-mantle boundary

Naohisa Hirao; Eiji Ohtani; Tadashi Kondo; Noriaki Endo; Toshiko Kuba; Toshiaki Suzuki; Takumi Kikegawa

doi:10.1029/2005GL025324

Partitioning of potassium between iron and silicate at the core-mantle boundary

Naohisa Hirao, Eiji Ohtani, Tadashi Kondo, Noriaki Endo, Toshiko Kuba, Toshiaki Suzuki, Takumi Kikegawa

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23 Citations (Scopus)

Abstract

Chemical reactions and the partitioning of potassium between metallic iron and potassium-silicate were studied at the core-mantle boundary (CMB) condition, 2900 km deep in the Earth, in a laser-heated diamond-anvil cell (LHDAC). Analytical transmission electron microscope (ATEM) analysis of the recovered samples from 134 GPa and 3500 K, prepared with Focused Ion Beam (FIB) techniques, revealed significant dissolution of potassium (0.8 wt.%) into molten iron, indicating that the partition coefficient of potassium between iron and silicate is 0.15. Our results show that the Earth's core can contain 35 ppm total potassium, i.e., 4.1 × 10^-3 PPM of ⁴⁰K, which could serve as a heat source corresponding to 0.23 TW in the Earth's core.

Original language	English
Article number	L08303
Journal	Geophysical Research Letters
Volume	33
Issue number	8
DOIs	https://doi.org/10.1029/2005GL025324
Publication status	Published - 2006 Apr 28
Externally published	Yes

ASJC Scopus subject areas

Geophysics
Earth and Planetary Sciences(all)

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10.1029/2005GL025324

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abstract = "Chemical reactions and the partitioning of potassium between metallic iron and potassium-silicate were studied at the core-mantle boundary (CMB) condition, 2900 km deep in the Earth, in a laser-heated diamond-anvil cell (LHDAC). Analytical transmission electron microscope (ATEM) analysis of the recovered samples from 134 GPa and 3500 K, prepared with Focused Ion Beam (FIB) techniques, revealed significant dissolution of potassium (0.8 wt.%) into molten iron, indicating that the partition coefficient of potassium between iron and silicate is 0.15. Our results show that the Earth's core can contain 35 ppm total potassium, i.e., 4.1 × 10-3 PPM of 40K, which could serve as a heat source corresponding to 0.23 TW in the Earth's core.",

author = "Naohisa Hirao and Eiji Ohtani and Tadashi Kondo and Noriaki Endo and Toshiko Kuba and Toshiaki Suzuki and Takumi Kikegawa",

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T1 - Partitioning of potassium between iron and silicate at the core-mantle boundary

AU - Hirao, Naohisa

AU - Ohtani, Eiji

AU - Kondo, Tadashi

AU - Endo, Noriaki

AU - Kuba, Toshiko

AU - Suzuki, Toshiaki

AU - Kikegawa, Takumi

PY - 2006/4/28

Y1 - 2006/4/28

N2 - Chemical reactions and the partitioning of potassium between metallic iron and potassium-silicate were studied at the core-mantle boundary (CMB) condition, 2900 km deep in the Earth, in a laser-heated diamond-anvil cell (LHDAC). Analytical transmission electron microscope (ATEM) analysis of the recovered samples from 134 GPa and 3500 K, prepared with Focused Ion Beam (FIB) techniques, revealed significant dissolution of potassium (0.8 wt.%) into molten iron, indicating that the partition coefficient of potassium between iron and silicate is 0.15. Our results show that the Earth's core can contain 35 ppm total potassium, i.e., 4.1 × 10-3 PPM of 40K, which could serve as a heat source corresponding to 0.23 TW in the Earth's core.

AB - Chemical reactions and the partitioning of potassium between metallic iron and potassium-silicate were studied at the core-mantle boundary (CMB) condition, 2900 km deep in the Earth, in a laser-heated diamond-anvil cell (LHDAC). Analytical transmission electron microscope (ATEM) analysis of the recovered samples from 134 GPa and 3500 K, prepared with Focused Ion Beam (FIB) techniques, revealed significant dissolution of potassium (0.8 wt.%) into molten iron, indicating that the partition coefficient of potassium between iron and silicate is 0.15. Our results show that the Earth's core can contain 35 ppm total potassium, i.e., 4.1 × 10-3 PPM of 40K, which could serve as a heat source corresponding to 0.23 TW in the Earth's core.

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Partitioning of potassium between iron and silicate at the core-mantle boundary

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