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Abstract
Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars’ deep mantle is demarcated by a seismic discontinuity arising from the pressure-induced phase transformation of the mineral olivine to its higher-pressure polymorphs, making the depth of this boundary sensitive to both mantle temperature and composition. Here, we report on the seismic detection of a midmantle discontinuity using the data collected by NASA’s InSight Mission to Mars that matches the expected depth and sharpness of the postolivine transition. In five teleseismic events, we observed triplicated P and S waves and constrained the depth of this discontinuity to be 1,006 ± 40 km by modeling the triplicated waveforms. From this depth range, we infer a mantle potential temperature of 1,605 ± 100 K, a result consistent with a crust that is 10 to 15 times more enriched in heat-producing elements than the underlying mantle. Our waveform fits to the data indicate a broad gradient across the boundary, implying that the Martian mantle is more enriched in iron compared to Earth. Through modeling of thermochemical evolution of Mars, we observe that only two out of the five proposed composition models are compatible with the observed boundary depth. Our geodynamic simulations suggest that the Martian mantle was relatively cold 4.5 Gyr ago (1,720 to 1,860 K) and are consistent with a present-day surface heat flow of 21 to 24 mW/m2.
Original language | English |
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Article number | e2204474119 |
Number of pages | 12 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 119 |
Issue number | 42 |
Early online date | 10 Oct 2022 |
DOIs | |
Publication status | Published - 18 Oct 2022 |
Bibliographical note
Funding Information:Siersch have received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement 724690). D.A. also acknowledges the support by CNES, focused on the SEIS instrument of the InSight mission. M.B., C. Bollinger, F.B., and C.M. acknowledge the CNES funding and Agence Nationale de la Recherche (ANR) MArs Geophysical InSight (MAGIS) (ANR-19-CE31-0008-08). T.G. acknowledges a government contract of the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. C. Beghein acknowledges NASA grant 80NSSC18K1679. J.C.E.I. acknowledges Science and Technology Facilities Council (STFC)/UKSA grant ST/W002515/1. A.H. was supported by STFC/UKSA Aurora grants ST/ R002096/1 and ST/W002523/1. B.F., K.L., and T.N.-M. were supported by STFC/ UKSA Aurora grant ST/S001379/1. M.P.P., S.E.S., and W.B.B were supported by the funding from JPL under a NASA contract (80NM0018D0004).
Funding Information:
ACKNOWLEDGMENTS. We thank the editor and two anonymous reviewers for their constructive comments. We acknowledge NASA; Centre National D’Etudes Spatiales (CNES); their partner agencies and Institutions (UK Space Agency [UKSA], Swiss Space Office [SSO], German Aerospace Center [DLR], Jet Propulsion Laboratory [JPL], IPGP–National Center for Scientific Research [CNRS], Eidg-en€ossische Technische Hochschule Z€urich [ETHZ], Imperial College [IC], and Max Planck Institute for Solar System Research [MPS-MPG]); and the flight operations team at JPL, SeIS on Mars Operations Center [SISMOC], Mars SEIS Data Service [MSDS], IRIS-DMC, and PDS for providing SEED SEIS data and mission support. This paper is InSight Contribution 203. Q.H., N. C. Schmerr, D.K., R.R.M., and F.K. acknowledge the funding from NASA grant 80NSSC18K1628 and NASA Solar System Exploration Research Virtual Institute (SSERVI) Cooperative Agreement 80NSSC19M0216. Q.H. and L.W. were supported by NSF grant EAR-1853662. Q.H. and E.B. acknowledge NASA grant 80NSSC18K1680. V.L. was supported by a Packard Foundation Fellowship. S.D.K. acknowledges NASA grant 80NSSC18K1623. A.R. was financially supported by the Belgian PROgramme for the Development of scientific EXperiments (PRODEX) program managed by the European Space Agency in collaboration with the Belgian Federal Science Policy Office. M.C. and A.-C.P. acknowledge the financial support and endorsement from the DLR Management Board Young Research Group Leader Program and the Executive Board Member for Space Research and Technology. R.M. was supported by a UKSA Aurora Research Fellowship (ST/R001332/1). D.A. and N. C.
Funding Information:
We thank the editor and two anonymous reviewers for their constructive comments. We acknowledge NASA; Centre National D’Etudes Spatiales (CNES); their partner agencies and Institutions (UK Space Agency [UKSA], Swiss Space Office [SSO], German Aerospace Center [DLR], Jet Propulsion Laboratory [JPL], IPGP–National Center for Scientific Research [CNRS], Eidgenössische Technische Hochschule Zärich [ETHZ], Imperial College [IC], and Max Planck Institute for Solar System Research [MPS-MPG]); and the flight operations team at JPL, SeIS on Mars Operations Center [SISMOC], Mars SEIS Data Service [MSDS], IRIS-DMC, and PDS for providing SEED SEIS data and mission support. This paper is InSight Contribution 203. Q.H., N. C. Schmerr, D.K., R.R.M., and F.K. acknowledge the funding from NASA grant 80NSSC18K1628 and NASA Solar System Exploration Research Virtual Institute (SSERVI) Cooperative Agreement 80NSSC19M0216. Q.H. and L.W. were supported by NSF grant EAR-1853662. Q.H. and E.B. acknowledge NASA grant 80NSSC18K1680. V.L. was supported by a Packard Foundation Fellowship. S.D.K. acknowledges NASA grant 80NSSC18K1623. A.R. was financially supported by the Belgian PROgramme for the Development of scientific EXperiments (PRODEX) program managed by the European Space Agency in collaboration with the Belgian Federal Science Policy Office. M.C. and A.-C.P. acknowledge the financial support and endorsement from the DLR Management Board Young Research Group Leader Program and the Executive Board Member for Space Research and Technology. R.M. was supported by a UKSA Aurora Research Fellowship (ST/R001332/1). D.A. and N. C. Siersch have received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement 724690). D.A. also acknowledges the support by CNES, focused on the SEIS instrument of the InSight mission. M.B., C. Bollinger, F.B., and C.M. acknowledge the CNES funding and Agence Nationale de la Recherche (ANR) MArs Geophysical InSight (MAGIS) (ANR-19-CE31-0008-08). T.G. acknowledges a government contract of the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. C. Beghein acknowledges NASA grant 80NSSC18K1679. J.C.E.I. acknowledges Science and Technology Facilities Council (STFC)/UKSA grant ST/W002515/1. A.H. was supported by STFC/UKSA Aurora grants ST/ R002096/1 and ST/W002523/1. B.F., K.L., and T.N.-M. were supported by STFC/ UKSA Aurora grant ST/S001379/1. M.P.P., S.E.S., and W.B.B were supported by the funding from JPL under a NASA contract (80NM0018D0004).
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Dive into the research topics of 'Seismic detection of a deep mantle discontinuity within Mars by InSight'. Together they form a unique fingerprint.Projects
- 3 Finished
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Exploring Mars' Core with InSight Seismic Data Yrs2+3
Irving, J. C. E. (Principal Investigator)
1/04/21 → 31/03/24
Project: Research, Parent
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Exploring Mars' Core with InSight Seismic Data Yr 1
Irving, J. C. E. (Principal Investigator)
1/04/21 → 31/03/22
Project: Research
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The thermochemical evolution and state of Mars' deep interior
Myhill, R. C. (Principal Investigator)
1/09/17 → 1/03/21
Project: Research