Stabilization of full-vector palaeosecular variation in the last 5 Myr: insights from a newly updated palaeointensity (PINT) data base

SUMMARY The palaeomagnetic intensity (PINT) data base documents variations in the full-vector of the ancient geomagnetic field that can be used to provide insights into the operation and evolution of the geodynamo. In this study, we report an update of PINT and the evolving behaviour of the palaeomagnetic field since 17 Ma. The update is the addition of 206 recently published site-mean data with ages between 0.06 and 2610 Ma that have been assessed using the palaeointensity quality criteria (QPI). Using this data base, we analysed, for the first time, the distribution of values of the palaeosecular variation index (PSVi) in intervals drawn from the past 17 Myr. Our results indicate that this index was enhanced prior to 5 Ma reflecting both lower average virtual dipole moments and higher angular deviations of the virtual geomagnetic pole from the geographic pole. The present Brunhes chron is highlighted as being associated with especially high measurements of dipole moment which we hypothesize may be related to its already long duration relative to most other chrons of the last 17 Myr.