Geochemistry, Geophysics, Geosystems (G3 or G-Cubed) is an online-only journal of the American Geophysical Union (AGU). It’s format means it is perfect for publishing papers with large supplementary information or appendices. That is definitely the case for this latest publication, lead-authored by Greig Paterson – a Scotsman in Beijing.

Measurements of the strength of the ancient magnetic field recorded in rocks  or archaeological materials (“palaeointensity” or “archaeointensity” measurements) can be very tricky to make. It would therefore be very useful to have some agreement amongst those people doing these experiments about what a reliable measurement looks like.  However, for one reason or another, such consensus has eluded the community for decades. This paper, we hope, is a step towards rectifying that. It uses the largest ever compilation of palaeointensity measurements made using only materials for which we know what the answer “is” (e.g. from lavas that cooled in recent times during which the magnetic field strength is independently known from observatory data). It then finds variants of currently used selection criteria that are better at picking out the reliable measurements than the originals. This stuff may not sound to the outsider as exciting as say, finding a new reversal, but it is the type of thing that underpins palaeomagnetism as a tool for understanding our planet better.