Extensive Lithological Diversity of Float Rocks at the Mount Washburn Mound in Neretva Vallis, Jezero Crater, Mars

J. R. Johnson; B. Garczynski; A. Vaughan; C. Bedford; E. Dehouck; O. Beyssac; V. Payre; B. Horgan; M. Rice; C. Royer; L. Mandon; P. Beck; C. Quantin-Nataf; Z. U. Wolf; S A Connell; S. Schroder; H. T. Manelski; R. Barnes; A. Jones; A. Klidaras; K. Lapo; M. Gabbert; O. Forni; P. Pilleri; R. C. Wiens; A. Cousin; A. Hayes; J F Bell III; J. N. Maki; S. Maurice; G. Paar; T. Fouchet

doi:10.1029/2025JE009439

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Extensive Lithological Diversity of Float Rocks at the Mount Washburn Mound in Neretva Vallis, Jezero Crater, Mars

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Extensive Lithological Diversity of Float Rocks at the Mount Washburn Mound in Neretva Vallis, Jezero Crater, Mars

J. R. Johnson, B. Garczynski, A. Vaughan, C. Bedford, E. Dehouck, O. Beyssac, V. Payre, B. Horgan, M. Rice, C. Royer, …

Journal of geophysical research. Planets, Vol.131(2), e2025JE009439

02/23/2026

DOI: 10.1029/2025JE009439

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Abstract

During its exploration of Neretva Vallis in Jezero crater, NASA's Mars 2020 Perseverance rover examined Mount Washburn, a set of light-toned sedimentary mounds that exhibited a diverse array of float rocks. Mastcam-Z visible/near-infrared (VISIR) multispectral imaging revealed five spectral types dominated by low-calcium pyroxene-bearing rocks, although olivine-bearing and ferric materials were also identified. SuperCam VISIR point spectroscopy of eight targets noted four spectral groups, including those with low-Ca pyroxene, hydrated alteration products, and phyllosilicates. SuperCam laser-induced breakdown spectroscopy data confirmed a wide compositional array among the targets. Overall, these data spanned much of the spectral and compositional range in rocks observed by Perseverance through Sol 1348, with no major outliers, although some rock textures were unique. The rock diversity at Mount Washburn is among the most extensive observed in situ at a single site on Mars, pointing to a multifaceted geological history. Bedrock beneath Mount Washburn exhibited high silica and iron content, closely resembling materials from the nearby Bright Angel sedimentary units and suggesting a possible stratigraphic link. Some geological models of Neretva Vallis are consistent with the idea that Bright Angel-like materials may have formed the foundation of Mount Washburn, with subsequent deposition of cobbles and boulders as late-stage fluvial events. These findings suggest that similar rocks-and possibly their source regions-may be encountered during future exploration of the Jezero crater rim and intracrater plains. Such materials would likely sample the olivine/carbonate-bearing regional units and/or ancient Noachian basement, reflecting the rich geological complexity of the Neretva Vallis watershed.

Physical Sciences

Geochemistry & Geophysics

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Title: Subtitle: Extensive Lithological Diversity of Float Rocks at the Mount Washburn Mound in Neretva Vallis, Jezero Crater, Mars
Creators: J. R. Johnson - Johns Hopkins University Applied Physics Laboratory
B. Garczynski - Western Washington University
A. Vaughan - Apogee Technology (United States)
C. Bedford - Purdue University West Lafayette
E. Dehouck - Université Claude Bernard Lyon 1
O. Beyssac - Centre National de la Recherche Scientifique
V. Payre - University of Iowa
B. Horgan - Purdue University West Lafayette
M. Rice - Western Washington University
C. Royer - Centre National de la Recherche Scientifique
L. Mandon - Centre National de la Recherche Scientifique
P. Beck - Centre National de la Recherche Scientifique
C. Quantin-Nataf - Université Claude Bernard Lyon 1
Z. U. Wolf - Los Alamos National Laboratory
S A Connell - Purdue University West Lafayette
S. Schroder - Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
H. T. Manelski - Purdue University West Lafayette
R. Barnes - Imperial College London
A. Jones - Imperial College London
A. Klidaras - Purdue University West Lafayette
K. Lapo - Western Washington University
M. Gabbert - Western Washington University
O. Forni - Centre National de la Recherche Scientifique
P. Pilleri - Centre National de la Recherche Scientifique
R. C. Wiens - Purdue University West Lafayette
A. Cousin - Centre National de la Recherche Scientifique
A. Hayes - Cornell University
J F Bell III - Arizona State University
J. N. Maki - Jet Propulsion Laboratory
S. Maurice - Centre National de la Recherche Scientifique
G. Paar - Universalmuseum Joanneum
T. Fouchet - Observatoire de Paris
Resource Type: Journal article
Publication Details: Journal of geophysical research. Planets, Vol.131(2), e2025JE009439
DOI: 10.1029/2025JE009439
ISSN: 2169-9097
eISSN: 2169-9100
Publisher: Amer Geophysical Union
Number of pages: 23
Grant note: Center National d'tudes Spatiales 101045260 / ERC; European Research Council (ERC) 1511125 / Jet Propulsion Laboratory 15-707/1511125 / Arizona State University NNH13ZDA018O / NASA; National Aeronautics & Space Administration (NASA)
Language: English
Date published: 02/23/2026
Academic Unit: School of Earth, Environment, and Sustainability
Record Identifier: 9985143023902771

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