Persistence and origin of the lunar core dynamo

• Main Authors: Suavet, Clement Romain (Contributor), Weiss, Benjamin P. (Contributor), Cassata, William S. (Author), Shuster, David L. (Author), Gattacceca, Jerome (Contributor), Chan, Lindsey (Author), Garrick-Bethell, Ian (Author), Head, James W. (Author), Grove, Timothy L. (Contributor), Fuller, Michael D. (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences (Contributor)
• Format: Article
• Language: English
• Published: National Academy of Sciences (U.S.), 2014-07-10T14:28:55Z.
• Subjects: Article
• Online Access: Get fulltext

The lifetime of the ancient lunar core dynamo has implications for its power source and the mechanism of field generation. Here, we report analyses of two 3.56-Gy-old mare basalts demonstrating that they were magnetized in a stable and surprisingly intense dynamo magnetic field of at least ∼13 μT. These data extend the known lifetime of the lunar dynamo by ∼160 My and indicate that the field was likely continuously active until well after the final large basin-forming impact. This likely excludes impact-driven changes in rotation rate as the source of the dynamo at this time in lunar history. Rather, our results require a persistent power source like precession of the lunar mantle or a compositional convection dynamo.
Massachusetts Institute of Technology (MIT-France Seed Funds Program)
Centre National de la Recherche Scientifique (France)
European Commission (Marie Sklodowska-Curie Actions, People Programme, Research Executive Agency Grant 298355)
Ann and Gordon Getty Foundation
United States. National Aeronautics and Space Administration (NASA Grant NNX12AH80G)