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Moon-forming impactor as a source of Earth's basal mantle anomalies.
Nature. 2023 Nov; 623(7985):95-99.Nat

Abstract

Seismic images of Earth's interior have revealed two continent-sized anomalies with low seismic velocities, known as the large low-velocity provinces (LLVPs), in the lowermost mantle[1]. The LLVPs are often interpreted as intrinsically dense heterogeneities that are compositionally distinct from the surrounding mantle[2]. Here we show that LLVPs may represent buried relics of Theia mantle material (TMM) that was preserved in proto-Earth's mantle after the Moon-forming giant impact[3]. Our canonical giant-impact simulations show that a fraction of Theia's mantle could have been delivered to proto-Earth's solid lower mantle. We find that TMM is intrinsically 2.0-3.5% denser than proto-Earth's mantle based on models of Theia's mantle and the observed higher FeO content of the Moon. Our mantle convection models show that dense TMM blobs with a size of tens of kilometres after the impact can later sink and accumulate into LLVP-like thermochemical piles atop Earth's core and survive to the present day. The LLVPs may, thus, be a natural consequence of the Moon-forming giant impact. Because giant impacts are common at the end stages of planet accretion, similar mantle heterogeneities caused by impacts may also exist in the interiors of other planetary bodies.

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Authors+Show Affiliations

Yuan Q
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA. qyuan@caltech.edu. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. qyuan@caltech.edu.
Li M
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
Desch SJ
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
Ko B
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA. Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA.
Deng H
Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai, China.
Garnero EJ
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
Gabriel TSJ
U.S. Geological Survey, Astrogeology Science Center, Flagstaff, AZ, USA.
Kegerreis JA
NASA Ames Research Center, Moffett Field, CA, USA.
Miyazaki Y
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
Eke V
Institute for Computational Cosmology, Department of Physics, Durham University, Durham, UK.
Asimow PD
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

37914947

Citation

Yuan, Qian, et al. "Moon-forming Impactor as a Source of Earth's Basal Mantle Anomalies." Nature, vol. 623, no. 7985, 2023, pp. 95-99.
Yuan Q, Li M, Desch SJ, et al. Moon-forming impactor as a source of Earth's basal mantle anomalies. Nature. 2023;623(7985):95-99.
Yuan, Q., Li, M., Desch, S. J., Ko, B., Deng, H., Garnero, E. J., Gabriel, T. S. J., Kegerreis, J. A., Miyazaki, Y., Eke, V., & Asimow, P. D. (2023). Moon-forming impactor as a source of Earth's basal mantle anomalies. Nature, 623(7985), 95-99. https://doi.org/10.1038/s41586-023-06589-1
Yuan Q, et al. Moon-forming Impactor as a Source of Earth's Basal Mantle Anomalies. Nature. 2023;623(7985):95-99. PubMed PMID: 37914947.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Moon-forming impactor as a source of Earth's basal mantle anomalies. AU - Yuan,Qian, AU - Li,Mingming, AU - Desch,Steven J, AU - Ko,Byeongkwan, AU - Deng,Hongping, AU - Garnero,Edward J, AU - Gabriel,Travis S J, AU - Kegerreis,Jacob A, AU - Miyazaki,Yoshinori, AU - Eke,Vincent, AU - Asimow,Paul D, Y1 - 2023/11/01/ PY - 2022/02/04/received PY - 2023/08/30/accepted PY - 2023/11/3/medline PY - 2023/11/2/pubmed PY - 2023/11/2/entrez SP - 95 EP - 99 JF - Nature JO - Nature VL - 623 IS - 7985 N2 - Seismic images of Earth's interior have revealed two continent-sized anomalies with low seismic velocities, known as the large low-velocity provinces (LLVPs), in the lowermost mantle[1]. The LLVPs are often interpreted as intrinsically dense heterogeneities that are compositionally distinct from the surrounding mantle[2]. Here we show that LLVPs may represent buried relics of Theia mantle material (TMM) that was preserved in proto-Earth's mantle after the Moon-forming giant impact[3]. Our canonical giant-impact simulations show that a fraction of Theia's mantle could have been delivered to proto-Earth's solid lower mantle. We find that TMM is intrinsically 2.0-3.5% denser than proto-Earth's mantle based on models of Theia's mantle and the observed higher FeO content of the Moon. Our mantle convection models show that dense TMM blobs with a size of tens of kilometres after the impact can later sink and accumulate into LLVP-like thermochemical piles atop Earth's core and survive to the present day. The LLVPs may, thus, be a natural consequence of the Moon-forming giant impact. Because giant impacts are common at the end stages of planet accretion, similar mantle heterogeneities caused by impacts may also exist in the interiors of other planetary bodies. SN - 1476-4687 UR - https://www.unboundmedicine.com/medline/citation/37914947/Moon_forming_impactor_as_a_source_of_Earth DB - PRIME DP - Unbound Medicine ER -
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