DOI: 10.1016/j.epsl.2020.116080
论文题名: Compression experiments to 126 GPa and 2500 K and thermal equation of state of Fe3S: Implications for sulphur in the Earth's core
作者: Thompson S. ; Komabayashi T. ; Breton H. ; Suehiro S. ; Glazyrin K. ; Pakhomova A. ; Ohishi Y.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 534 语种: 英语
中文关键词: diamond anvil cell
; Earth's core
; equation of state
; Fe-S alloys
; high-pressure
; in-situ XRD
英文关键词: Equations of state
; X ray diffraction
; Diamond-anvil cell
; Earth's core
; Equation of state
; High pressure
; In-situ XRD
; Iron alloys
; alloy
; compression
; core (planetary)
; diamond anvil cell
; equation of state
; high pressure
; high temperature
; in situ measurement
; iron
; sulfur
; X-ray diffraction
英文摘要: Pressure-volume-temperature (P-V-T) experiments on tetragonal Fe3S were conducted to 126 GPa and 2500 K in laser-heated diamond anvil cells (DAC) with in-situ X-ray diffraction (XRD). Seventy nine high-T data as well as four 300-K data were collected, based on which new thermal equations of state (EoS) for Fe3S were established. The room-T data together with existing data were fitted to the third order Birch-Murnaghan EoS, which yielded, K0=126±2 GPa and K′=5.1±1 with V0 fixed at 377.0 Å3. A constant αKT term in the thermal pressure equation, Pth = αKT(T-300), fitted the high-T data well to the highest temperature, which implies that the contributions from the anharmonic and electronic terms should be minor in the thermal pressure term. The high-T data were also fitted to the Mie-Grüneisen-Debye model; γ0=1.01±0.03 with θ0 and q fixed at 417 K and 1 respectively. Calculations from the EoS show that crystalline Fe3S at 4000-5500 K is denser than the Earth's outer core and less dense than the inner core. Assuming a density reduction due to melting, liquid Fe3S would meet the outer core density profile, which however suggests that no less than 16 wt%S is needed to reconcile the observed outer core density deficit. The S-rich B2 phase, which was suggested to be a potential liquidus phase of an Fe3S-outer core above 250 GPa, namely the main constituent of its solid inner core, would likely be less dense than the Earth's inner core. As such, while the outer core density requires as much sulphur as 16 wt%, the resulting liquidus phase cannot meet the density of the inner core. Any sulphur-rich composition should therefore be rejected for the Earth's core. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165311
Appears in Collections: 气候变化与战略
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作者单位: School of GeoSciences, Centre for Science at Extreme Conditions, University of EdinburghEH9 3FE, United Kingdom; Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8551, Japan; Deutsches Elektronen-Synchrotron (DESY), Photon Science, Notkestrasse 85, Hamburg, 22607, Germany; SPring-8, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gunHyogo 679-5198, Japan
Recommended Citation:
Thompson S.,Komabayashi T.,Breton H.,et al. Compression experiments to 126 GPa and 2500 K and thermal equation of state of Fe3S: Implications for sulphur in the Earth's core[J]. Earth and Planetary Science Letters,2020-01-01,534