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Partitioning of potassium between iron and silicate at the core‐mantle boundary
Author(s) -
Hirao Naohisa,
Ohtani Eiji,
Kondo Tadashi,
Endo Noriaki,
Kuba Toshiko,
Suzuki Toshiaki,
Kikegawa Takumi
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl025324
Subject(s) - potassium , mantle (geology) , silicate , mineralogy , dissolution , analytical chemistry (journal) , potassium silicate , materials science , geology , chemistry , inorganic chemistry , geochemistry , environmental chemistry , metallurgy , organic chemistry
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 40 K, which could serve as a heat source corresponding to 0.23 TW in the Earth's core.