Paleomagnetic record of Martian meteorite ALH84001

Maria Antretter, Mike Fuller, Edward Scott, Mike Jackson, Bruce Moskowitz, Peter Solheid

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

The natural remanent magnetization (NRM) of the Martian meteorite ALH84001 is predominantly carried by fine magnetite, which is found in association with carbonate. The magnetite is in epitaxial and topotactic relation with the carbonate and formed from the carbonate in the major impact event at 4.0 Ga. The NRM will therefore record this field. The local preferential crystallographic and shape alignment of the magnetite defines local easy directions of magnetization may account for the observed inhomogeneity of the NRM on a microscopic scale. Normalizing the intensity of the NRM by the saturation isothermal remanence (IRMs) then gives an estimate for the 4.0 Ga Martian field one order smaller than the present geomagnetic field. Such a field is unlikely to be strong enough to generate the high-intensity Martian magnetic anomalies. ALH 84001 in its pristine state as an orthopyroxenite is not a plausible source rock for the Martian anomalies because its magnetite was not formed until the 4.0 Ga event.

Original languageEnglish (US)
Pages (from-to)3-1
Number of pages3
JournalJournal of Geophysical Research E: Planets
Volume108
Issue number6
StatePublished - Jun 25 2003

    Fingerprint

Keywords

  • ALH84001
  • Extraterrestrial paleomagnetism
  • Martian magnetic fields
  • Martian meteorites
  • Martian paleomagnetism
  • Origin of magnetite in ALH84001

Cite this