Rhodri Davies¹, Andrew P Valentine¹, Stephan C Kramer², Nicholas Rawlinson³, Mark Hoggard⁴, Caroline M Eakin⁵ and Cian R Wilson⁶, (1)Australian National University, Research School of Earth Sciences, Canberra, ACT, Australia, (2)Imperial College, London, United Kingdom, (3)Bullard Laboratories, Cambridge, United Kingdom, (4)Harvard University, Department of Earth and Planetary Sciences, Cambridge, United States, (5)Australian National University, Research School of Earth Sciences, Canberra, Australia, (6)Carnegie Institution for Science, Department of Terrestrial Magnetism, Washington, DC, United States