We are pleased to announce a School Seminar by Claire Nichols on the topic of: The Curious Case of the Lunar Dynamo.
Abstract
The history of the Moon’s magnetic field remains one of the major open questions in planetary science. Palaeomagnetic measurements from Apollo samples suggest that the Moon once generated a long-lived magnetic field, but its strength, timing, and behaviour are still debated. In particular, some studies indicate extended periods of weak or absent magnetism, while others point to episodes of surprisingly strong fields early in lunar history. In this talk I will discuss our recent research where we combined palaeomagnetic, geochemical, and rock magnetic data from lunar basalts to better understand this variability. We identify a link between the strength of recorded magnetic fields and the titanium content of the host rocks, suggesting that episodes of strong magnetism may be tied to specific volcanic processes. Thermal modelling further indicates that these events could reflect intermittent dynamo activity driven by heat flow associated with the melting of titanium-rich material deep within the Moon. To complement this, I will also present new measurements from Apollo 17 basalts that provide both the strength and direction of the lunar magnetic field around 3.7 billion years ago. These samples record a relatively strong field and offer rare constraints on its geometry, consistent with (but not uniquely requiring) a dipolar field, supporting magnetic field generation within the lunar interior. Together, these results support a picture of the lunar dynamo as intermittent rather than steady, with magnetic field generation potentially linked to episodic interior processes and volcanism.