DOI: 10.1016/j.epsl.2020.116285
论文题名: Thermal state and solidification regime of the martian core: Insights from the melting behavior of FeNi-S at 20 GPa
作者: Gilfoy F. ; Li J.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 541 语种: 英语
中文关键词: core crystallization
; dynamo
; iron snow
; liquidus curve
; Mars
; phase diagram
英文关键词: Iron
; Solidification
; Sulfur
; Core composition
; Core-mantle boundary
; Crystallization regimes
; Higher sulfur contents
; Liquidus curve
; Melting behavior
; Sulfur contents
; Surface observation
; Iron compounds
; core (planetary)
; core-mantle boundary
; fractional crystallization
; Mars
; partial melting
; solidification
; temperature anomaly
英文摘要: A series of multi-anvil experiments have been conducted to define the iron-rich liquidus of the iron-nickel-sulfur (FeNi-S) system at 20 GPa, the estimated pressure of the martian core-mantle boundary (CMB). The liquidus curve of FeNi-S containing about 9 wt.% Ni has a concave up shape, and is as much as 400 K lower than the liquidi previously applied to the martian core with sparse experimental constraints. Unlike existing liquidi of Fe-S and FeNi-S at 23 GPa, which predict a fully molten core for a narrow range of sulfur content between 14 and 15 wt.% S, our results are consistent with a molten state for all proposed core compositions, and establishes a new minimum CMB temperature of 1500 K for 10 wt.% S and 1250 K for 16 wt.% S. Extrapolating our FeNi-S liquidus to high pressures and comparing it to calculated areotherms, we find that three core crystallization regimes are possible. For a martian core with moderate sulfur content (10 to 13 wt.%) or lower, crystallization takes the form of iron snow near the CMB, while for cores with higher sulfur content (15-16 wt.%), solidification occurs near the center of the planet in the form of solid Fe3S. At an intermediate sulfur content of 14 wt.%, Fe3S would precipitate over a broad depth range and may appear fully molten to surface observations. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164986
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States
Recommended Citation:
Gilfoy F.,Li J.. Thermal state and solidification regime of the martian core: Insights from the melting behavior of FeNi-S at 20 GPa[J]. Earth and Planetary Science Letters,2020-01-01,541