Exceptional secular variation recorded in Neolithic hearths, Orkney and Swedish lake sediments
Geomagnetic field models constrained by direct observations extend back some 400 years and the magnitude of decadal to centennial variations that they display is often assumed to be typical of the secular variation over longer timescales. Here we present archaeomagnetic directions from layered Neolithic hearths in Orkney, dating to around 3000 BCE, that challenge this assumption. Combining stratig
