Timing of the martian dynamo: New constraints for a core field 4.5 and 3.7 Ga ago

A. Mittelholz, C. L. Johnson, J. M. Feinberg, B. Langlais, R. J. Phillips

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56 Scopus citations

Abstract

The absence of crustal magnetic fields above the martian basins Hellas, Argyre, and Isidis is often interpreted as proof of an early, before 4.1 billion years (Ga) ago, or late, after 3.9 Ga ago, dynamo. We revisit these interpretations using new MAVEN magnetic field data. Weak fields are present over the 4.5-Ga old Borealis basin, with the transition to strong fields correlated with the basin edge. Magnetic fields, confined to a near-surface layer, are also detected above the 3.7-Ga old Lucus Planum. We conclude that a dynamo was present both before and after the formation of the basins Hellas, Utopia, Argyre, and Isidis. A long-lived, Earth-like dynamo is consistent with the absence of magnetization within large basins if the impacts excavated large portions of strongly magnetic crust and exposed deeper material with lower concentrations of magnetic minerals.

Original languageEnglish (US)
Article numbereaba0513
JournalScience Advances
Volume6
Issue number18
DOIs
StatePublished - Apr 2020

Bibliographical note

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Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

PubMed: MeSH publication types

  • Journal Article

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