Impactor material records the ancient lunar magnetic field in antipodal anomalies
| Autor: | R. E. Maxwell, Shigeru Wakita, Brandon C. Johnson, M. R. Kelley, Thomas M. Davison, Ian Garrick-Bethell |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Multidisciplinary
Magnetism Astrophysics::High Energy Astrophysical Phenomena Science General Physics and Astronomy Field strength Crust General Chemistry Geophysics Rings and moons General Biochemistry Genetics and Molecular Biology Article Magnetic field Physics::Geophysics Magnetization Mathematics::Quantum Algebra Physics::Space Physics Curie temperature Astrophysics::Earth and Planetary Astrophysics Early solar system Ejecta Geology Dynamo |
| Zdroj: | Nature Communications Nature Communications, Vol 12, Iss 1, Pp 1-7 (2021) |
| ISSN: | 2041-1723 |
| Popis: | The Moon presently has no dynamo, but magnetic fields have been detected over numerous portions of its crust. Most of these regions are located antipodal to large basins, leading to the hypothesis that lunar rock ejected during basin-forming impacts accumulated at the basin antipode and recorded the ambient magnetic field. However, a major problem with this hypothesis is that lunar materials have low iron content and cannot become strongly magnetized. Here we simulate oblique impacts of 100-km-diameter impactors at high resolution and show that an ~700 m thick deposit of potentially iron-rich impactor material accumulates at the basin antipode. The material is shock-heated above the Curie temperature and therefore may efficiently record the ambient magnetic field after deposition. These results explain a substantial fraction of the Moon’s crustal magnetism, and are consistent with a dynamo field strength of at least several tens of microtesla during the basin-forming epoch. Antipodes of large basins on the moon exhibit large areas of crustal magnetism. Here, the authors show that antipodal ejecta contains sufficient impactor material to explain the observed magnetization. |
| Databáze: | OpenAIRE |
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