| DOI: | 10.1016/j.epsl.2019.115923
|
| 论文题名: | Core formation and geophysical properties of Mars |
| 作者: | Brennan M.C.; Fischer R.A.; Irving J.C.E.
|
| 刊名: | Earth and Planetary Science Letters
|
| ISSN: | 0012821X
|
| 出版年: | 2020
|
| 卷: | 530 | | 语种: | 英语
|
| 中文关键词: | core formation
; Fe–S alloys
; InSight
; Mars
; Martian core
|
| 英文关键词: | Economic and social effects
; Metals
; Seismic waves
; Silicates
; Structural geology
; Chemical and physical properties
; Core formation
; Geophysical properties
; InSight
; Mars
; Martian core
; Multi stage modeling
; Normal-mode frequencies
; Seismology
; alloy
; core (planetary)
; core-mantle boundary
; geophysical survey
; iron
; Mars
; parameterization
; partitioning
; silicate
; sulfur
|
| 英文摘要: | The chemical and physical properties of the interiors of terrestrial planets are largely determined during their formation and differentiation. Modeling a planet's formation provides important insights into the properties of its core and mantle, and conversely, knowledge of those properties may constrain formational narratives. Here, we present a multi-stage model of Martian core formation in which we calculate core–mantle equilibration using parameterizations from high pressure–temperature metal–silicate partitioning experiments. We account for changing core–mantle boundary (CMB) conditions, composition-dependent partitioning, and partial equilibration of metal and silicate, and we evolve oxygen fugacity (fO2) self-consistently. The model successfully reproduces published meteorite-based estimates of most elemental abundances in the bulk silicate Mars, which can be used to estimate core formation conditions and core composition. This composition implies that the primordial material that formed Mars was significantly more oxidized (0.9–1.4 log units below the iron–wüstite buffer) than that of the Earth, and that core–mantle equilibration in Mars occurred at 42–60% of the evolving CMB pressure. On average, at least 84% of accreted metal and at least 40% of the mantle were equilibrated in each impact, a significantly higher degree of metal equilibration than previously reported for the Earth. In agreement with previous studies, the modeled Martian core is rich in sulfur (18–19 wt%), with less than one weight percent O and negligible Si. We have used these core and mantle compositions to produce physical models of the present-day Martian interior and evaluate the sensitivity of core radius to crustal thickness, mantle temperature, core composition, core temperature, and density of the core alloy. Trade-offs in how these properties affect observable physical parameters like planetary mass, radius, moment of inertia, and tidal Love number k2 define a range of likely core radii: 1620–1870 km. Seismic velocity profiles for several combinations of model parameters have been used to predict seismic body-wave travel times and planetary normal mode frequencies. These results may be compared to forthcoming Martian seismic data to further constrain core formation conditions and geophysical properties. © 2019 Elsevier B.V. |
| Citation statistics: |
|
| 资源类型: | 期刊论文
|
| 标识符: | http://119.78.100.158/handle/2HF3EXSE/164887
|
| Appears in Collections: | 气候变化与战略
|
|
There are no files associated with this item.
|
|
作者单位: | Harvard University, Department of Earth and Planetary Sciences, United States; Princeton University, Department of Geosciences, United States
|
| Recommended Citation: | |
Brennan M.C.,Fischer R.A.,Irving J.C.E.. Core formation and geophysical properties of Mars[J]. Earth and Planetary Science Letters,2020-01-01,530
|
|
|