Strontium isotopes (87Sr/86Sr) provide valuable information to help reconstruct past mobility. For the analysis of archaeological tooth enamel to provide a direct assessment of mobility, a comparison to the baseline 87Sr/86Sr in a region is required. In this study, a large-scale 87Sr/86Sr baseline of Portugal is created based on 151 paired plant and soil leachate samples combined with previously published data (20 additional plant and 33 additional soil leachate sites). Spatial patterns of 87Sr/86Sr are evident, following Portugal's geology and terrain, with higher 87Sr/86Sr in the granite dominated north and further inland. Influences from sea spray are observed along the coastal regions of the country.
Neodymium isotopic composition (εNd) has enjoyed widespread use as a palaeotracer, principally because it behaves quasi-conservatively in the modern ocean. However, recent bottom water εNd reconstructions from the eastern North Atlantic are difficult to interpret under assumptions of conservative behaviour. The observation that this apparent departure from conservative behaviour increases with enhanced ice-rafted debris (IRD) fluxes has resulted in the suggestion that IRD leads to the overprinting of bottom water εNd through reversible scavenging. In this study, a simple water column model successfully reproduces εNd reconstructions from the eastern North Atlantic at the Last Glacial Maximum and Heinrich Stadial 1, and demonstrates that the changes in scavenging intensity required for good model-data fit is in good agreement with changes in the observed IRD flux.
Love this stuff. Shame that I don't have time to reacquaint myself with current research.
Thanks!