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AGU: Journal of Geophysical Research, Planets

 

Keywords

  • Mars
  • Mars Exploration Rover
  • Meridiani Planum
  • hematite
  • jarosite
  • sulfate

Index Terms

  • Mineral Physics: NMR, Mossbauer spectroscopy, and other magnetic techniques
  • Planetary Sciences: Solid Surface Planets: Erosion and weathering
  • Planetary Sciences: Solid Surface Planets: Surface materials and properties
  • Planetary Sciences: Solid Surface Planets: Instruments and techniques
  • Planetary Sciences: Solar System Objects: Mars
Abstract
Cited By (63)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, E12S15, 27 PP., 2006
doi:10.1029/2006JE002791

Mössbauer mineralogy of rock, soil, and dust at Meridiani Planum, Mars: Opportunity's journey across sulfate-rich outcrop, basaltic sand and dust, and hematite lag deposits

R. V. Morris

NASA Johnson Space Center, Houston, Texas, USA

G. Klingelhöfer

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

C. Schröder

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

D. S. Rodionov

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

Space Research Institute IKI, Moscow, Russia

A. Yen

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA

D. W. Ming

NASA Johnson Space Center, Houston, Texas, USA

P. A. de Souza Jr.

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

CVRD Group, Rio de Janeiro, Brazil

T. Wdowiak

Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama, USA

I. Fleischer

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

R. Gellert

Department of Physics, University of Guelph, Guelph, Ontario, Canada

B. Bernhardt

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

U. Bonnes

Darmstadt University of Technology, Darmstadt, Germany

B. A. Cohen

Institute of Meteoritics, University of New Mexico, Albuquerque, NM, USA

E. N. Evlanov

Space Research Institute IKI, Moscow, Russia

J. Foh

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

Darmstadt University of Technology, Darmstadt, Germany

P. Gütlich

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

E. Kankeleit

Darmstadt University of Technology, Darmstadt, Germany

T. McCoy

Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA

D. W. Mittlefehldt

NASA Johnson Space Center, Houston, Texas, USA

F. Renz

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany

M. E. Schmidt

Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA

B. Zubkov

Space Research Institute IKI, Moscow, Russia

S. W. Squyres

Department of Astronomy, Cornell University, Ithaca, New York, USA

R. E. Arvidson

Department Earth and Planetary Sciences, Washington University, St. Louis, Missouri, USA

The Mössbauer (MB) spectrometer on Opportunity measured the Fe oxidation state, identified Fe-bearing phases, and measured relative abundances of Fe among those phases at Meridiani Planum, Mars. Eight Fe-bearing phases were identified: jarosite (K,Na,H3O)(Fe,Al)(OH)6(SO4)2, hematite, olivine, pyroxene, magnetite, nanophase ferric oxides (npOx), an unassigned ferric phase, and metallic Fe (kamacite). Burns Formation outcrop rocks consist of hematite-rich spherules dispersed throughout S-rich rock that has nearly constant proportions of Fe3+ from jarosite, hematite, and npOx (29%, 36%, and 20% of total Fe). The high oxidation state of the S-rich rock (Fe3+/FeT ∼ 0.9) implies that S is present as the sulfate anion. Jarosite is mineralogical evidence for aqueous processes under acid-sulfate conditions because it has structural hydroxide and sulfate and it forms at low pH. Hematite-rich spherules, eroded from the outcrop, and their fragments are concentrated as hematite-rich soils (lag deposits) on ripple crests (up to 68% of total Fe from hematite). Olivine, pyroxene, and magnetite are primarily associated with basaltic soils and are present as thin and locally discontinuous cover over outcrop rocks, commonly forming aeolian bedforms. Basaltic soils are more reduced (Fe3+/FeT ∼ 0.2–0.4), with the fine-grained and bright aeolian deposits being the most oxidized. Average proportions of total Fe from olivine, pyroxene, npOx, magnetite, and hematite are ∼33%, 38%, 18%, 6%, and 4%, respectively. The MB parameters of outcrop npOx and basaltic-soil npOx are different, but it is not possible to infer mineralogical information beyond octahedrally coordinated Fe3+. Basaltic soils at Meridiani Planum and Gusev crater have similar Fe-mineralogical compositions.

Received 13 July 2006; accepted 9 November 2006; published 30 December 2006.

Citation: Morris, R. V., et al. (2006), Mössbauer mineralogy of rock, soil, and dust at Meridiani Planum, Mars: Opportunity's journey across sulfate-rich outcrop, basaltic sand and dust, and hematite lag deposits, J. Geophys. Res., 111, E12S15, doi:10.1029/2006JE002791.

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