Thermal constraints on the survival of primitive blobs in the lower mantle

Recent reports of age underestimations for events of interest in both palaeoclimatology and archaeology have led to questioning the validity of using luminescence for dating sediments. The commonly designated culprit is anomalous fading of feldspar luminescence. We investigated the differential fading rates of single feldspar grains in sediment samples from different geological domains of North America and deduced how one could extrapolate to zero fading. This is shown to resolve an extreme case of optical age underestimation documented for the Late Pleistocene Norfolk Formation, a key palaeoclimate stratigraphic unit exposed along the North American Atlantic Coast.