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Multispectral Observations of Float Rocks Used to Investigate the Origin of Boulders on the Western Jezero Fan Front, Mars
  • +19
  • Bavani Sundre Kathir,
  • Meiissa S Rice,
  • Briony Heather Noelle Horgan,
  • Lucia Mandon,
  • Jeffrey R. Johnson,
  • Kathryn Stack,
  • Adrian P Broz,
  • Nathan Robert Williams,
  • Nicolas Mangold,
  • Roger C. Wiens,
  • Justin I. Simon,
  • Candice C. Bedford,
  • Andreas Bechtold,
  • Bradley J Garczynski,
  • Alicia Fallacaro Vaughan,
  • Nicolas Randazzo,
  • R. Aileen Yingst,
  • Samantha Anne Theuer,
  • Gerhard Paar,
  • Jesús Martínez-Frías,
  • Jorge I. Núñez,
  • Thierry Fouchet
Bavani Sundre Kathir
Western Washington University

Corresponding Author:[email protected]

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Meiissa S Rice
Western Washington University
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Briony Heather Noelle Horgan
Purdue University
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Lucia Mandon
California Institute of Technology
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Jeffrey R. Johnson
Johns Hopkins University Applied Physics Laboratory
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Kathryn Stack
Jet Propulsion Laboratory
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Adrian P Broz
Purdue University
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Nathan Robert Williams
Jet Propulsion Lab
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Nicolas Mangold
UMR6112, LPG/CNRS, Nantes Université, France
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Roger C. Wiens
Purdue University
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Justin I. Simon
Center for Isotope Cosmochemistry and Geochronology, Astromaterials Research and Exploration Science, NASA Johnson Space Center
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Candice C. Bedford
Purdue University
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Andreas Bechtold
Department of Lithospheric Research
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Bradley J Garczynski
Purdue University
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Alicia Fallacaro Vaughan
US Geological Survey Astrogeology Science Center
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Nicolas Randazzo
Department of Earth and Atmospheric Sciences, University of Alberta
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R. Aileen Yingst
Planetary Science Institute
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Samantha Anne Theuer
Western Washington University
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Gerhard Paar
JOANNEUM RESEARCH
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Jesús Martínez-Frías
Instituto de Geociencias, IGEO (CSIC-UCM).
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Jorge I. Núñez
Johns Hopkins University Applied Physics Laboratory
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Thierry Fouchet
Observatoire de Paris
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Abstract

The Mars 2020 Perseverance rover has explored the escarpment at the front of the western fan in Jezero crater, Mars, where it encountered a variety of rock units as in-place outcrops and as loose pieces of rock separated from outcrops, or “float” rocks. Comparing float rocks to in-place outcrops can provide key insights into the crater’s erosional history and the diversity of units in the Jezero watershed that the Perseverance rover cannot visit in-situ. Here, we used multispectral observations from Perseverance’s Mastcam-Z instrument to investigate the lithology and origin of float rocks found on the western Jezero fan front (sols 415-707). We identified four textural classes of float rocks (conglomerates, layered, massive, and light-toned) and investigated their physical characteristics, spectral properties, and distribution to interpret their source and constrain their mode of transport. We found that the conglomerate and layered float rocks are highly spectrally variable and altered with differing ferric and ferrous signatures, and they likely derived from local sedimentary outcrops in the western fan front. Massive float rocks are the least altered, exhibit ferrous signatures, and could have derived from local outcrop sources or more distal sources in the Jezero watershed. Massive float rocks separate into two subclasses: massive olivine and massive pyroxene, which likely derived from the regional olivine-carbonate-bearing watershed unit and the crustal Noachian basement unit respectively. The unique light-toned float rocks have variable hydration and low Fe-abundance, but there are no local outcrop equivalent of these rocks in the western Jezero fan or crater floor.