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Partial Deoxygenation and Dehydration of Ferric Oxyhydroxide in Earth's Subducting Slabs
Author(s) -
Gan Bo,
Zhang Youjun,
Huang Yuqian,
Li Xiaohong,
Wang Qiming,
Li Jun,
Zhuang Yukuai,
Liu Yun,
Jiang Gang
Publication year - 2021
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 - 10.1029/2021gl094446
Subject(s) - geology , mantle (geology) , pyrite , ferric iron , earth (classical element) , geochemistry , hydrogen , mineralogy , materials science , chemistry , metallurgy , ferrous , physics , mathematical physics , organic chemistry
The thermal stability of hydrous minerals in Earth's deep interior is key to understanding the evolution and physicochemical states of the planet. The recently discovered pyrite‐type (Py) FeO 2 H x ( x ≤ 1) phase, which can be transformed from α/ε‐FeOOH at ∼80 GPa, is believed to be a crucial candidate in transporting water and hydrogen to the lowermost mantle through subducting slabs. Here, we examined the stability and decomposition behavior of FeOOH through a set of shock‐recovery experiments up to ∼70 GPa and ∼2,750 K. Our results show that FeOOH partially decomposes to iron oxides Fe 2 O 3 and Fe 3 O 4 at 35–70 GPa and 1,150–2,750 K, which indicates that H 2 O and O 2 are released during the decomposition of FeOOH in subducting slabs. The released H 2 O and O 2 may have altered the physical and chemical properties of the surrounding mantle and contributed to the oxidation of surface Earth.