DOI: 10.1016/j.epsl.2018.08.055
Scopus记录号: 2-s2.0-85052918710
论文题名: Prospects for an ancient dynamo and modern crustal remanent magnetism on Venus
作者: O'Rourke J.G. ; Gillmann C. ; Tackley P.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 502 起始页码: 46
结束页码: 56
语种: 英语
英文关键词: accretion
; magnetic fields
; Venus
; Venus, interior
; Venus, surface
Scopus关键词: Coremaking
; Ionosphere
; Magnesia
; Magnetic fields
; Magnetite
; Silica
; Thermal conductivity
; accretion
; Atmospheric evolution
; Canonical models
; Future spacecraft
; Magnetic dynamos
; Surface strengths
; Venus
; Volcanic resurfacing
; Interactive devices
; accretion
; computer simulation
; crustal structure
; geomagnetism
; magnetic field
; numerical model
; remanent magnetization
; Venus
; Calluna vulgaris
英文摘要: Venus lacks an internally generated magnetic field today. Whether one existed in the past is unknown, but critical to atmospheric evolution and potential habitability. Canonical models assume the core of Venus is cooling too slowly for convection and thus a magnetic dynamo to occur today. Core/mantle heat flow is suppressed in these models after a putative transition in mantle dynamics associated with widespread, volcanic resurfacing. However, recent studies of impact craters and other surface features support more steady heat loss over geologic time. Precipitation of MgO and/or SiO2 from the core can also drive compositional convection even with slow cooling. Here we reevaluate the likelihood that Venus has an “Earth-like” (at least partially liquid and chemically homogeneous) core using numerical simulations of the coupled atmosphere–surface–mantle–core evolution. An Earth-like core is only compatible with the modern lack of a dynamo if the thermal conductivity of core material is towards the higher end of modern estimates (i.e., >100 W m−1 K−1). If lower estimates like ∼40–50 W m−1 K−1 are actually correct, then we favor recent proposals that the core has completely solidified or preserved primordial stratification. Any simulation initialized with a homogeneous, liquid core predicts a global magnetic field with Earth-like surface strength for >2–3 billion years after accretion—consistent with all available observations—and also sporadic activity within the surface age while temperatures remain below the Curie point of magnetite. Therefore, future spacecraft missions should prioritize the first-ever magnetometer measurements below the ionosphere to search for crustal remanent magnetism. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109649
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: School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States; Royal Observatory of Belgium, Brussels, Belgium; Free University of Brussels, Department of Geosciences, G-Time, Brussels, Belgium; Department of Earth Sciences, ETH Zurich, Institute of Geophysics, Zurich, Switzerland
Recommended Citation:
O'Rourke J.G.,Gillmann C.,Tackley P.. Prospects for an ancient dynamo and modern crustal remanent magnetism on Venus[J]. Earth and Planetary Science Letters,2018-01-01,502