Palaeomagnetic field strength variations suggest a Mesoproterozoic age of inner core nucleation

Andrew John Biggin1,2, Elisa J Piispa3, Lauri J Pesonen4, Richard T Holme1, Greig A Paterson5, Toni Veikkolainen4 and Lisa Tauxe6, (1)University of Liverpool, Liverpool, L69, United Kingdom, (2)University of Liverpool, Earth, Ocean and Ecological Sciences, Liverpool, L69, United Kingdom, (3)Michigan Technological University, Houghton, United States, (4)Univ Helsinki, Helsinki, Finland, (5)Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China, (6)Scripps Institution of Oceanography, University of California San Diego, La Jolla, United States