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

Andrew John Biggin1, Elisa J Piispa2, Lauri J Pesonen3, Richard T Holme4, Greig A Paterson5, Toni Veikkolainen3 and Lisa Tauxe6, (1)University of Liverpool, Department of Earth, Ocean and Ecological Sciences, Liverpool, United Kingdom, (2)Michigan Technological University, Houghton, United States, (3)Univ Helsinki, Helsinki, Finland, (4)University of Liverpool, Liverpool, L69, United Kingdom, (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