A new hydrous iron oxide phase stable at mid-mantle pressures
Journal Article
·
· Earth and Planetary Science Letters
- China Univ. of Geosciences, Hubei (China); Arizona State Univ., Tempe, AZ (United States)
- Hunan Univ. (China)
- Arizona State Univ., Tempe, AZ (United States)
- Yonsei Univ., Seoul (South Korea)
- Univ. of Chicago, IL (United States)
- Argonne National Lab. (ANL), Argonne, IL (United States)
The amount of hydrogen stored in the Earth's interior is important for a range of issues, including the volatile incorporation during the Earth formation and the co-evolution of the atmosphere, the hydrosphere, and the interior. Recent experiments found titanium bearing ε-FeOOH in a hydrous basaltic system at 12–19 GPa and 1300 K. Pyrite-type FeOOH was found to be stable at pressures higher than 80 GPa. These discoveries suggest possible hydrogen storage in the mantle transition zone and in the mantle below 1800 km depths, respectively. However, it remains uncertain how the potential deep hydrogen storage can be connected to the shallower storage. Here, we report a new hydrous iron oxide (η-Fe12O18+x/2Hx, x ≈ 2) stable at pressures between the stability fields of the ε- and the pyrite-type FeOOH. Our experiment also shows that the new η phase can exist together with the major lower mantle minerals including bridgmanite and periclase, making it an important hydrogen-bearing phase in the Earth's deep interior. Because of its limited H2O storage capacity, which is less than 1/6 of the storage capacity of the pyrite-type phase and the ε phase, the stability of the η phase would result in H2O loss during water transport in the mid mantle and therefore limit the amount of H2O potentially stored in the Fe–O–H system of the lower mantle. As a result, the large channel in the crystal structure of the η phase could provide potential storage sites for other volatile elements in the deep mantle.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- NASA; National Science Foundation (NSF), Directorate for Geosciences Division of Earth Sciences (GEO/EAR); USDOE; W.M. Keck Foundation
- Grant/Contract Number:
- AC02-06CH11357; FG02-94ER14466
- OSTI ID:
- 1864759
- Alternate ID(s):
- OSTI ID: 1657647
- Journal Information:
- Earth and Planetary Science Letters, Journal Name: Earth and Planetary Science Letters Vol. 550; ISSN 0012-821X
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phase transitions in ε-FeOOH at high pressure and ambient temperature
Experimental Evidence for Partially Dehydrogenated ε-FeOOH
Hydrogen-Bond Symmetrization Breakdown and Dehydrogenation Mechanism of FeO2 H at High Pressure
Journal Article
·
Mon Nov 30 19:00:00 EST 2020
· American Mineralogist
·
OSTI ID:1736252
Experimental Evidence for Partially Dehydrogenated ε-FeOOH
Journal Article
·
Fri Jul 12 20:00:00 EDT 2019
· Crystals
·
OSTI ID:1544838
Hydrogen-Bond Symmetrization Breakdown and Dehydrogenation Mechanism of FeO2 H at High Pressure
Journal Article
·
Wed Aug 23 20:00:00 EDT 2017
· Journal of the American Chemical Society
·
OSTI ID:1474063