Title: The internal structure and geodynamics of Mars inferred from a 4.2-Gyr zircon record

Abstract

Combining U–Pb ages with Lu–Hf data in zircon provides insights into the magmatic history of rocky planets. The Northwest Africa (NWA) 7034/7533 meteorites are samples of the southern highlands of Mars containing zircon with ages as old as 4476.3 ± 0.9 Ma, interpreted to reflect reworking of the primordial Martian crust by impacts. We extracted a statistically significant zircon population (n= 57) from NWA 7533 that defines a temporal record spanning 4.2 Gyr. Ancient zircons record ages from 4485.5 ± 2.2 Ma to 4331.0 ± 1.4 Ma, defining a bimodal distribution with groupings at 4474 ± 10 Ma and 4442 ± 17 Ma. We interpret these to represent intense bombardment episodes at the planet’s surface, possibly triggered by the early migration of gas giant planets. The unradiogenic initial Hf-isotope composition of these zircons establishes that Mars’s igneous activity prior to ~4.3 Ga was limited to impact-related reworking of a chemically enriched, primordial crust. A group of younger detrital zircons record ages from 1548.0 ± 8.8 Ma to 299.5 ± 0.6 Ma. The only plausible sources for these grains are the temporally associated Elysium and Tharsis volcanic provinces that are the expressions of deep-seated mantle plumes. The chondritic-like Hf-isotope compositions ofmore » these zircons require the existence of a primitive and convecting mantle reservoir, indicating that Mars has been in a stagnant-lid tectonic regime for most of its history. Our results imply that zircon is ubiquitous on the Martian surface, providing a faithful record of the planet’s magmatic history.« less

Authors:

Costa, Maria M. ^[1]; Jensen, Ninna K. ^[1]; Bouvier, Laura C. ^[1]; Connelly, James N. ^[1]; Mikouchi, Takashi  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-9998-8754"

Horstwood, Matthew A.  ^[3];

• Search DOE PAGES for author "Horstwood, Matthew A."
• Search DOE PAGES for ORCID "0000-0003-4200-8193"

Suuronen, Jussi-Petteri  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-1632-761X"

Moynier, Frédéric ^[5]; Deng, Zhengbin  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-4141-9241"

Agranier, Arnaud ^[6]; Martin, Laure J. ^[7]; Johnson, Tim E.  ^[8];

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• Search DOE PAGES for ORCID "0000-0001-8704-4396"

Nemchin, Alexander A. ^[8]; Bizzarro, Martin  ^[9]

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• Search DOE PAGES for ORCID "0000-0001-9966-2124"

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+ Show Author Affiliations

1. Univ. of Copenhagen (Denmark)
2. Univ. of Tokyo (Japan)
3. British Geological Survey, Nottingham (United Kingdom)
4. European Synchrotron Radiation Facility (ESRF), Grenoble (France)
5. Univ. of Paris (France)
6. Univ. de Bretagne Occidentale (France)
7. Univ. of Western Australia, Perth, WA (Australia)
8. Curtin Univ., Perth, WA (Australia)
9. Univ. of Copenhagen (Denmark); Univ. of Paris (France)

Publication Date:

Mon Nov 16 00:00:00 EST 2020

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)

Sponsoring Org.:

USDOE Office of Science (SC); Carlsberg Foundation; Danish Research Foundation; European Research Council (ERC); Australian Research Council

OSTI Identifier:

1734929

Grant/Contract Number:  

AC02-06CH11357; CF18_1105; DNRF97; 833275; DP190103849

Resource Type:

Accepted Manuscript

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Volume: 117; Journal Issue: 49; Journal ID: ISSN 0027-8424

Publisher:

National Academy of Sciences

Country of Publication:

United States

Language:

ENGLISH

Subject:

58 GEOSCIENCES; Mars; meteorites; ziricon; geodynamics