Elasticity and Anisotropy of the Pyrite-Type FeO2H-FeO2 System in Earth’s Lowermost Mantle
| Autor: | Shan Qin, Xiang Wu, Shengxuan Huang |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
Hydrogen Isotropy chemistry.chemical_element engineering.material 010502 geochemistry & geophysics 01 natural sciences Mantle (geology) Physics::Geophysics chemistry Ultra low velocity zone S-wave engineering General Earth and Planetary Sciences Astrophysics::Earth and Planetary Astrophysics Pyrite Elasticity (economics) Anisotropy Petrology Geology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Earth Science. 30:1293-1301 |
| ISSN: | 1867-111X 1674-487X |
| Popis: | The pyrite-type FeO2H-FeO2 system has been experimentally confirmed to be stable in Earth’s lowermost mantle but there is limited information about its physical properties at high pressures constraining our understanding of its potential geophysical implications for the deep Earth. Here, static calculations demonstrate that the pyrite-type FeO2H-FeO2 system has a high density and Poisson’s ratio and ultra-low seismic velocities at conditions of Earth’s lowermost mantle. It provides a plausible mechanism for the origin of ultra-low velocity zones at Earth’s D″ layer. The incorporation of hydrogen in the pyrite-type FeO2H-FeO2 system tends to decrease the S wave velocity (VS) but increase the bulk sound velocity (VΦ), and can potentially explain the observed anti-correlation of VS and VΦ in the lowermost mantle. Additionally, FeO2H exhibits nearly isotropic whereas FeO2 is highly anisotropic, which may help understand some seismic anisotropies at the core-mantle boundary. |
| Databáze: | OpenAIRE |
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