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Manganese oxides in Martian meteorites Northwest Africa (NWA) 7034 and 7533

Liu, Yang and Fischer, Woodward W. and Ma, Chi and Beckett, John R. and Tschauner, Oliver and Guan, Yunbin and Lingappa, Usha F. and Webb, Samuel M. and Prakapenka, Vitali B. and Lanza, Nina L. and Agee, Carl B. (2021) Manganese oxides in Martian meteorites Northwest Africa (NWA) 7034 and 7533. Icarus, 364 . Art. No. 114471. ISSN 0019-1035. doi:10.1016/j.icarus.2021.114471.

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We report the discovery of indigenous Mn-oxides in Martian regolith breccias Northwest Africa (NWA) 7034 and 7533. These Mn-oxides occur in Mn-rich regions as nanocrystals mixed with silicates, FeOOH, and possible phosphates. The Mn-rich regions contain up to 34 wt% Mn and typically display large chemical gradients on the scale of 10–20 μm. The Martian origin of Mn-oxides was established by the presence of Mn-rich glass (4.8–5.6 wt% Mn) in the fusion crust that crosscuts a Mn-oxides-bearing monzonite clast and by the absence of Mn-oxides on the environmentally exposed surfaces (exterior and fractures) of the meteorites. Manganese K-edge X-ray absorption spectrum (XAS) of the Mn-rich glass in the fusion crust indicated that this glass included high-valent Mn species. Synchrotron micro-X-ray diffraction of a Mn-rich region in a basalt clast and XAS of Mn-rich regions in three monzonite clasts indicate Mn-oxides in these regions are dominantly hollandite-structured with 67–85 mol% of the total Mn being Mn4+. The fact that Mn-rich regions are present in diverse petrological associations but are absent in the matrix of the breccias indicates that the Mn-oxides formed through surface alteration prior to the final brecciation event that assembled NWA 7034 and 7533. Thus, the age of the Mn-oxides is older than the lithification age (arguably 1.35 Ga) of NWA 7034 and 7533. Together with findings of Mn-rich phases within Noachian and Hesperian sedimentary strata in Endeavour and Gale craters, our results suggest that Mn-oxides are a common weathering product on Mars, suggesting aqueous environment on the Martian surface with high redox potential.

Item Type:Article
Related URLs:
URLURL TypeDescription
Fischer, Woodward W.0000-0002-8836-3054
Ma, Chi0000-0002-1828-7033
Tschauner, Oliver0000-0003-3364-8906
Guan, Yunbin0000-0002-7636-3735
Lingappa, Usha F.0000-0001-5691-6788
Webb, Samuel M.0000-0003-1188-0464
Prakapenka, Vitali B.0000-0001-9270-2330
Lanza, Nina L.0000-0003-4445-7996
Additional Information:© 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license ( Received 7 January 2021, Revised 19 February 2021, Accepted 6 April 2021, Available online 20 April 2021. A portion of this research was performed at the Jet Propulsion Laboratory (JPL), which is managed by the California Institute of Technology (Caltech) under the contract with NASA. We thank M. Newville and A. Lanzirotti at the Argonne National Laboratory for their assistance in synchrotron X-ray diffraction analysis and E. Stolper for providing NWA 7533 samples. An older version of the manuscript benefited greatly from critical reviews by two anonymous reviewers, E.B. Rampe, M. Humayun, and J. Catalano. We thank E.B. Rampe for handling this manuscript and careful and constructive reviews by A. Udry and P. Gasda. YL thanks the support from the JPL-Caltech President's and Director's Fund. WWF acknowledges the support of the Simons Foundation Collaboration on the Origins of Life (SCOL), and UL a NSF Graduate Research Fellowship. Portions of the research were carried out at the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. The SSRL Structural Molecular Biology Program is supported by the DOE Office of Biological and Environmental Research, and by the National Institutes of Health, National Institute of General Medical Sciences. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA’s Office of Experimental Sciences. The Advanced Photon Source is a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. The EPMA and SEM analyses were performed at the Caltech Geological and Planetary Science Division Analytical Facility, which was supported in part by NSF grants EAR-0318518 and DMR-00800065. Declaration of Competing Interest: None.
Funding AgencyGrant Number
JPL President and Director's FundUNSPECIFIED
Simons FoundationUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Department of Energy (DOE)DE-AC02-06CH11357
Subject Keywords:Mars; Oxygen; Mn-oxides; Atmosphere
Record Number:CaltechAUTHORS:20210511-101552611
Persistent URL:
Official Citation:Yang Liu, Woodward W. Fischer, Chi Ma, John R. Beckett, Oliver Tschauner, Yunbin Guan, Usha F. Lingappa, Samuel M. Webb, Vitali B. Prakapenka, Nina L. Lanza, Carl B. Agee, Manganese oxides in Martian meteorites Northwest Africa (NWA) 7034 and 7533, Icarus, Volume 364, 2021, 114471, ISSN 0019-1035, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109077
Deposited By: Tony Diaz
Deposited On:11 May 2021 21:40
Last Modified:12 May 2021 16:11

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