title: Persistence and origin of the lunar core dynamo.
abstract: 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.
authors: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. csuavet@mit.edu
authors: Clément
authors: C
authors: Suavet
authors: Benjamin P
authors: BP
authors: Weiss
authors: William S
authors: WS
authors: Cassata
authors: David L
authors: DL
authors: Shuster
authors: Jérôme
authors: J
authors: Gattacceca
authors: Lindsey
authors: L
authors: Chan
authors: Ian
authors: I
authors: Garrick-Bethell
authors: James W
authors: JW
authors: Head
authors: Timothy L
authors: TL
authors: Grove
authors: Michael D
authors: MD
authors: Fuller
keywords: high-K mare basalts; paleomagnetism
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