Search for magnetic minerals in Martian rocks: Overview of the Rock Abrasion Tool (RAT)magnet investigation on Spirit and Opportunity

Walter Goetz, Kristoffer Leer, Haraldur P. Gunnlaugsson, Paul Bartlett, Brandon Basso, Jim Bell, Preben Bertelsen, Charlotte S. Binau, Phillip C. Chu, S. Gorevan, Mikkel F. Hansen, Stubbe F. Hviid, Kjartan M. Kinch, Göstar Klingelhöfer, Alastair Kusack, Morten B. Madsen, Douglas W. Ming, Richard V. Morris, Erik Mumm, Tom MyrickMalte Olsen, Steven W. Squyres, Jack Wilson, Albert Yen

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

The Rock Abrasion Tool (RAT) on board the Mars Exploration Rovers (MER) is a grinding tool designed to remove dust coatings and/or weathering rinds from rocks and expose fresh rock material. Four magnets of different strengths that are built into the structure of the RAT have been attracting substantial amounts of magnetic material during RAT activities from rocks throughout both rover missions. The RAT magnet experiment as performed on Spirit demonstrates the presence of a strongly ferrimagnetic phase in Gusev crater rocks, which based on Mössbauer and visible/near-infrared reflectance spectra is interpreted as magnetite. The amount of abraded rock material adhering to the magnets varied strongly during the mission and is correlated in a consistent way to the amount of magnetite inferred from Mössbauer spectra for the corresponding rock. The RAT magnet experiment as performed on Opportunity also indicates the presence of a strongly ferrimagnetic phase in outcrops, such as magnetite or an altered version of magnetite. However, the evidence is weaker than in the case of Spirit. According to data from the α particle X-ray spectrometer (APXS) and the Mössbauer spectrometer (MB), the Eagle crater outcrops should not contain magnetite and their magnetization should not exceed 0.03 A m2 kg-1. However, this assertion seems to be in contradiction with the results of the RAT magnet experiment. The evidence for a strongly ferrimagnetic phase at low abundance in the Meridiani outcrops is discussed.

Original languageEnglish (US)
Article numberE05S90
JournalJournal of Geophysical Research E: Planets
Volume113
Issue number5
DOIs
StatePublished - May 20 2008
Externally publishedYes

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ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Goetz, W., Leer, K., Gunnlaugsson, H. P., Bartlett, P., Basso, B., Bell, J., Bertelsen, P., Binau, C. S., Chu, P. C., Gorevan, S., Hansen, M. F., Hviid, S. F., Kinch, K. M., Klingelhöfer, G., Kusack, A., Madsen, M. B., Ming, D. W., Morris, R. V., Mumm, E., ... Yen, A. (2008). Search for magnetic minerals in Martian rocks: Overview of the Rock Abrasion Tool (RAT)magnet investigation on Spirit and Opportunity. Journal of Geophysical Research E: Planets, 113(5), [E05S90]. https://doi.org/10.1029/2006JE002819