Bioavailable soil and rock strontium isotope data from Israel

Strontium isotope ratios (87Sr = 86Sr) of biogenic material such as bones and teeth reflect the local sources of strontium ingested as food and drink during their formation. This has led to the use of strontium isotope ratios as a geochemical tracer in a wide range of fields including archaeology, ecology, food studies and forensic sciences. In order to utilise strontium as a geochemical tracer, baseline data of bioavailable 87Sr = 86Sr in the region of interest are required, and a growing number of studies have developed reference maps for this purpose in various geographic regions, and over varying scales. This study presents a new data set of bioavailable strontium isotope ratios from rock and soil samples across Israel, as well as from sediment layers from seven key archaeological sites. This data set may be viewed and accessed both in an Open Science Framework repository (https://doi.org/10.17605/OSF.IO/XKJ5Y, Moffat et al., 2020) or via the IRHUM (Isotopic Reconstruction of Human Migration) database.

The IRHUM (Isotopic Reconstruction of Human Migration) database – bioavailable strontium isotope ratios for geochemical fingerprinting in France

Strontium isotope ratios (87Sr / 86Sr) are a key geochemical tracer used in a wide range of fields including archaeology, ecology, food and forensic sciences. These applications are based on the principle that the Sr isotopic ratios of natural materials reflect the sources of strontium available during their formation. A major constraint for current studies is the lack of robust reference maps to evaluate the source of strontium isotope ratios measured in the samples. Here we provide a new data set of bioavailable Sr isotope ratios for the major geologic units of France, based on plant and soil samples (Pangaea data repository doi:10.1594/PANGAEA.819142). The IRHUM (Isotopic Reconstruction of Human Migration) database is a web platform to access, explore and map our data set. The database provides the spatial context and metadata for each sample, allowing the user to evaluate the suitability of the sample for their specific study. In addition, it allows users to upload and share their own data sets and data products, which will enhance collaboration across the different research fields. This article describes the sampling and analytical methods used to generate the data set and how to use and access the data set through the IRHUM database. Any interpretation of the isotope data set is outside the scope of this publication.

Mapping of bioavailable strontium isotope ratios in France for archaeological provenance studies

Strontium isotope ratios (87Sr/86Sr) of archaeological samples (teeth and bones) can be used to track mobility and migration across geologically distinct landscapes. However, traditional interpolation algorithms and classification approaches used to generate Sr isoscapes are often limited in predicting multiscale 87Sr/86Sr patterning. Here we investigate the suitability of plant samples and soil leachates from the IRHUM database (www. irhumdatabase.com) to create a bioavailable 87Sr/86Sr map using a novel geostatistical framework. First, we generated an 87Sr/86Sr map by classifying 87Sr/86Sr values into five geologically representative isotope groups using cluster analysis. The isotope groups were then used as a covariate in kriging to integrate prior geological knowledge of Sr cycling with the information contained in the bioavailable dataset and enhance 87Sr/86Sr predictions. Our approach couples the strengths of classification and geostatistical methods to generate more accurate 87Sr/86Sr predictions (Root Mean Squared Error=0.0029) with an estimate of spatial uncertainty based on lithology and sample density. This bioavailable Sr isoscape is applicable for provenance studies in France, and the method is transferable to other areas with high sampling density. While our method is a step forward in generating accurate 87Sr/86Sr isoscapes, the remaining uncertainty also demonstrates that finemodelling of 87Sr/86Sr variability is challenging and requires more than geological maps for accurately predicting 87Sr/86Sr variations across the landscape. Future efforts should focus on increasing sampling density and developing predictive models to further quantify and predict the processes that lead to 87Sr/86Sr variability.

Baseline bioavailable strontium and oxygen isotope mapping of the Adelaide Region

Strontium and oxygen isotopes provide a useful method for provenancing bioapaties, such as teeth and bone. In order for this approach to be successful, regional baseline bioavailable isotope data are required; however, few databases are currently available in Australia. This study measured stable oxygen and bioavailable strontium isotope ratios from low mobility fauna sampled from the major geological and physiographic provinces in Adelaide, South Australia in order to create a database for this region. Bioavailable strontium isotope ratios (87Sr/86Sr) obtained from the predominantly siliciclastic metasediments of the Neoproterozoic Adelaide Geosyncline have a range of 0.7122 ± 0.0001 to 0.7202 ± 0.0001. Cainozoic samples (dominantly terrestrial fluvial/lacustrine and marine carbonate sediments) from the Adelaide Plains have values in the range of 0.7098 ± 0.0002 to 0.7121 ± 0.0001. Samples from the alluvial fan sediments near the Eden-Burnside Fault at the boundary between these regions have values of 0.7131 ± 0.0001 to 0.7143 ± 0.0001. Stable oxygen isotope results range from 9.5 to 4.5‰ δ18OC (VPDB) and do not appear to vary systematically based on elevation, temperature, rainfall or humidity. These results demonstrate that strontium isotopes are potentially a useful tool for provenance studies within the Adelaide area. Oxygen is probably a more appropriate tool for discriminating seasonality rather than location within the study region. This research also suggests that rats are better suited for mapping strontium isoscapes than koalas, and that, while (non-systematic) offsets appear to exist between laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) and thermal ionisation mass spectrometry (TIMS) data, this effect is considerably less than the variation between geological provenances in the region.

Bioavailable soil and rock strontium isotope data from Israel

Strontium isotope ratios (87Sr ∕ 86Sr) of biogenic material such as bones and teeth reflect the local sources of strontium ingested as food and drink during their formation. This has led to the use of strontium isotope ratios as a geochemical tracer in a wide range of fields including archaeology, ecology, food studies and forensic sciences. In order to utilise strontium as a geochemical tracer, baseline data of bioavailable 87Sr ∕ 86Sr in the region of interest are required, and a growing number of studies have developed reference maps for this purpose in various geographic regions, and over varying scales. This study presents a new data set of bioavailable strontium isotope ratios from rock and soil samples across Israel, as well as from sediment layers from seven key archaeological sites. This data set may be viewed and accessed both in an Open Science Framework repository (https://doi.org/10.17605/OSF.IO/XKJ5Y, Moffat et al., 2020) or via the IRHUM (Isotopic Reconstruction of Human Migration) database.