Percorrer por autor "James, Hannah F."
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- A large-scale environmental strontium isotope baseline map of Portugal for archaeological and paleoecological provenance studiesPublication . James, Hannah F.; Adams, Shaun; Willmes, Malte; Mathison, Kate; Ulrichsen, Andrea; Wood, Rachel; Valera, António Carlos; Frieman, Catherine J.; Grün, RainerStrontium isotopes (Sr-87/Sr-86) 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 Sr-87/Sr-86 in a region is required. In this study, a large-scale Sr-87/Sr-86 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 Sr-87/Sr-86 are evident, following Portugal's geology and terrain, with higher Sr-87/Sr-86 in the granite dominated north and further inland. Influences from sea spray are observed along the coastal regions of the country. The bioavailable strontium range for Portugal is 0.70575-0.73487, and paired plant-soil leachate site measurements show a strong positive relationship. Empirical Bayesian Kriging (EBK) alongside mean Sr-87/Sr-86 per geological unit are used to provide predictive surfaces for bioavailable Sr-87/Sr-86. We find that the addition of archaeological site-specific measurements is required in archaeological mobility studies to ensure local-scale Sr-87/Sr-86 variation is captured, illustrated in this study using the Late Middle Neolithic to Early Bronze Age site of Perdigoes. The bioavailable strontium isoscape for Portugal provides a baseline map for future archaeological and palaeoecological studies in this region and contributes to the global efforts to map strontium isotope variability.
- Strontium isoscapes for provenance, mobility and migration: the way forward.Publication . Spies, Maximilian J.; Alblas, Amanda; Ambrose, Stanley H.; Barakat, Sarah; Barberena, Ramiro; Bataille, Clément; Bowen, Gabriel J.; Britton, Kate; Cawthra, Hayley; Diamond, Roger; Dosseto, Anthony; Evans, Jane A.; Fisher, Erich Christopher; Gray, Kerryn; Heddell-Stevens, Phoebe; Holt, Emily; James, Hannah F.; Janzen, Anneke; Le Corré, Mael; le Roux, Petrus; Lee-Thorp, Julia; Mackay, Alexander; McNeill, Patricia J.; Montgomery, Janet; Mugabe, Bedone; Oelze, Vicky M.; Pfab, Michèle; Richards, Michael P.; Samec, Celeste T.; Santana-Sagredo, Francisca; Serna, Alejandro; Stantis, Chris; Snoeck, Christophe; Stewart, Brian; Stuurman, Cameron; Tarrant, Damon; West, Adam G.; Winter-Schuh, Christine; Sealy, JudithStrontium isotopes (87Sr/86Sr) are increasingly used as a provenance tool in multiple disciplines. Application to biological materials requires knowledge of the variation in bioavailable 87Sr/86Sr across the landscape, potentially in the form of an isoscape (a quantitative model of spatial isotopic variability). This paper summarizes and provides advice on our current understanding of the main concerns in creating and interpreting isoscapes of bioavailable 87Sr/86Sr. Isoscape creation approaches include domain mapping, geostatistical contour mapping and machine learning, the last becoming more readily achievable with the availability of software packages. It is critically important to develop isoscapes at a resolution appropriate for addressing the research questions. Choice of sample materials depends on the research questions and availability: plants or fauna with small ranges are favoured, with some analytes (snails, soil leachates) posing challenges. Interpreting 87Sr/ 86Sr in biological tissues requires considering Sr metabolism and the timing of tissue formation, thus far underappreciated. The numerous sources of error involved in developing and applying isoscapes must be recognized to avoid over-interpreting data and spurious provenance precision. We hope this paper will help researchers investigating provenance, mobility, landscape use and migration to develop the most appropriate isoscapes for their purposes, and possible future use by others.