DOI: 10.1016/j.epsl.2018.05.032
Scopus记录号: 2-s2.0-85047509827
论文题名: Influence of sulfur on the electrical resistivity of a crystallizing core in small terrestrial bodies
作者: Pommier A.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 496 起始页码: 37
结束页码: 46
语种: 英语
英文关键词: crystallization regimes
; electrical resistivity
; iron alloys
; planetary cores
Scopus关键词: Electric conductivity
; Electromagnetic field effects
; Iron alloys
; Iron compounds
; Silicon compounds
; Sulfur
; Thermal conductivity
; Crystallization regimes
; Electrical experiments
; Equilibrium crystallization
; Fractional crystallization
; Increasing temperatures
; Multi-anvil apparatus
; planetary cores
; Resistivity variation
; Sulfur compounds
; alloy
; electrical resistivity
; electrode
; fractional crystallization
; iron
; magnetic field
; sulfur
; terrestrial environment
; thermal conductivity
英文摘要: Electrical experiments were performed on core analogues in the Fe–S system and on FeSi2 up to 8 GPa and 1850 °C in the multi-anvil apparatus. Electrical resistivity was measured using the four-electrode method. For all samples, resistivity increases with increasing temperature. The higher the S content, the higher the resistivity and the resistivity increase upon melting. At 4.5 GPa, liquid FeS is up to >10 times more resistive than Fe-5 wt.% S and twice more resistive than FeSi2, suggesting a stronger influence of S than Si on liquid resistivity. Electrical results are used to develop crystallization-resistivity paths considering both equilibrium and fractional crystallization in the Fe–S system. At 4.5 GPa, equilibrium crystallization, as expected locally in thin snow zones during top-down core crystallization, presents electrical resistivity variations from about 300 to 190 microhm-cm for a core analogue made of Fe-5 wt.%S, depending on temperature. Fractional crystallization, which is relevant to core-scale cooling, leads to more important electrical resistivity variations, depending on S distribution across the core, temperature, and pressure. Estimates of the lower bound of thermal resistivity are calculated using the Wiedemann–Franz law. Comparison with previous works indicates that the thermal conductivity of a metallic core in small terrestrial bodies is more sensitive to the abundance of alloying agents than that of the Earth's core. Application to Ganymede using core adiabat estimates from previous studies suggests important thermal resistivity variations with depth during cooling, with a lower bound value at the top of the core that can be as low as 3 W/m K. It is speculated that the generation and sustainability of a magnetic field in small terrestrial bodies might be favored in light element-depleted cores. © 2018 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109800
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: UC San Diego, Scripps Institution of Oceanography, Institute of Geophysics and Planetary Physics, La Jolla, CA, United States
Recommended Citation:
Pommier A.. Influence of sulfur on the electrical resistivity of a crystallizing core in small terrestrial bodies[J]. Earth and Planetary Science Letters,2018-01-01,496