Home | Contact Us | Sitemap | 中文 | CAS | Director's Email
 
Location:Home > Papers > Recent Papers
Superionic iron oxide-hydroxide in Earth's deep mantle TEXT SIZE: A A A

Water ice becomes a superionic phase under the high pressure and temperature conditions of deep planetary interiors of ice planets such as Neptune and Uranus, which affects interior structures and generates magnetic fields. The solid Earth, however, contains only hydrous minerals with a negligible amount of ice. Here we combine high pressure and temperature electrical conductivity experiments, Raman spectroscopy and first-principles simulations to investigate the state of hydrogen in the pyrite-type FeO2Hx (x <= 1), which is a potential H-bearing phase near the core-mantle boundary. We find that when the pressure increases beyond 73 GPa at room temperature, symmetric hydroxyl bonds are softened and the H+ (or proton) becomes diffusive within the vicinity of its crystallographic site. Increasing temperature under pressure, the diffusivity of hydrogen is extended beyond the individual unit cell to cover the entire solid, and the electrical conductivity soars, indicating a transition to the superionic state, which is characterized by freely moving protons and a solid FeO2 lattice. The highly diffusive hydrogen provides fresh transport mechanisms for charge and mass, which dictate the geophysical behaviours of electrical conductivity and magnetism, as well as geochemical processes of redox, hydrogen circulation and hydrogen isotopic mixing in Earth's deep mantle.

Publication name

 NATURE GEOSCIENCE Volume: 14 Issue: 3 Pages: 174-+ DOI: 10.1038/s41561-021-00696-2 Published: MAR 2021

Author(s)

 Hou, Mingqiang; He, Yu; Jang, Bo Gyu; Sun, Shichuan; Zhuang, Yukai; Deng, Liwei; Tang, Ruilian; Chen, Jiuhua; Ke, Feng; Meng, Yue; Prakapenka, Vitali B.; Chen, Bin; Shim, Ji Hoon; Liu, Jin; Kim, Duck Young; Hu, Qingyang; Pickard, Chris J.; Needs, Richard J.; Mao, Ho-Kwang

Corresponding author(s) 

 Liu, Jin; Kim, Duck Young; Hu, Qingyang
jin.liu@hpstar.ac.cn; duckyoung.kim@hpstar.ac.cn; qingyang.hu@hpstar.ac.cn  
 Ctr High Pressure Sci & Technol Adv Res HPSTAR, Beijing, Peoples R China.

Author(s) from IGCAS   HE Yu; SUN Shichuan

View here for the details 

Copyright © Institute Of Geochemistry, Chinese Academy of Sciences All Rights Reserved.
Address: 99 West Lincheng Road, Guanshanhu District, Guiyang, Guizhou Province 550081, P.R.China
Tel: +86-851-85895239 Fax: +86-851-85895239 Email: web_en@mail.gyig.ac.cn