A strontium isoscape of north‐east Australia for human provenance and repatriation

Abstract

It has been estimated that up to 25% of Indigenous human remains held in Australian institutions are unprovenanced. Geochemical tracers like strontium isotope ratios (87Sr/86Sr) have been used globally for over 40 years to discern human provenance and provide independent data to aid in repatriation efforts. To reliably apply this technology, landscape 87Sr/86Sr isotope ratio variability must be quantified. In Australia, only a few studies have used this technique and they are lacking in detail. Here, we present Australia's first regional strontium isotope ratio variability study. We measured strontium isotope ratios in soil, plant, water, and faunal material throughout Cape York, Queensland, the most northerly point of mainland Australia. Results show a close correlation between surface soil leachates, vegetation, surface water, and faunal 87Sr/86Sr results with extremely high values (0.78664) associated with ancient Precambrian geology. Our study suggests that measuring 87Sr/86Sr in soil and plant samples offer a reliable approach for assessing regional Sr isotope distribution, although the inclusion of mammal and freshwater samples is also important to assess exogenous inputs. This study provides an important tool for modern and prehistoric provenance studies and may aid in answering some of Australia's most enduring archaeological questions.

A strontium isoscape for the Conchucos region of highland Peru and its application to Andean archaeology

“…In recent years there has also been an increased effort to create large-scale isoscapes, a spatially explicit prediction of isotopic variation across landscapes [42,[102][103][104][105]]. An isoscape considers all published 87 Sr/ 86 Sr data for a given region and uses this dataset to extrapolate the extent of possible 87 Sr/ 86 Sr values across large geographic areas [71,75,[106][107][108][109][110][111]. While these studies provide invaluable insight into the nature of past mobility on a population-wide panregional scale, they are dependent on the amount and quality of data used to generate the isoscape.…”

Drinking Locally: A Water 87Sr/86Sr Isoscape for Geolocation of Archeological Samples in the Peruvian Andes

“…Because the 87 Sr/ 86 Sr of mixed-source isotopic catchments vary predictably across the landscape, models of baseline or reference landscape 87 Sr/ 86 Sr have become essential for reconstructing movements across the landscape throughout human history (Fisher et al, 2010;Frei and Frei, 2011;Laffoon et al, 2012;Knudson et al, 2014;Grupe et al, 2017a,b;Bataille et al, 2018;Willmes et al, 2018;Adams et al, 2019;Hoogewerff et al, 2019;Lengfelder et al, 2019;Scaffidi and Knudson, 2020). Isoscapes are spatially explicit models of isotope variability (Bowen, 2010;Ehleringer et al, 2010;Wunder, 2010;West et al, 2014;Pellegrini et al, 2016).…”

“…Isoscapes are spatially explicit models of isotope variability (Bowen, 2010;Ehleringer et al, 2010;Wunder, 2010;West et al, 2014;Pellegrini et al, 2016). Archeological and anthropological isoscapes have most commonly utilized a geostatistical kriging method to model isotopic variability across the landscape, which relies on underlying spatial auto-correlation in GPS-located isotope measurements to predict isotope values at unsampled locations (Copeland et al, 2016;Pellegrini et al, 2016;Wang et al, 2018;Willmes et al, 2018;Adams et al, 2019;Scaffidi and Knudson, 2020). Geostatistical models have been improved on in recent years by process-based isoscapes that rely on regression or machine learning methods to predict isotope variability as a function of environmental variables Bataille et al, 2014Bataille et al, , 2020Hoogewerff et al, 2019)these are rare in archeological and anthropological applications but are becoming more common (Bataille et al, , 2018Hoogewerff et al, 2019;Zimmer-Dauphinee et al, 2020).…”

“…Process and regression-based methods are ultimately necessary for developing high-resolution models of human 87 Sr/ 86 Sr variability (Hoogewerff et al, 2019;Bataille et al, 2020;Serna et al, 2020). Notwithstanding these limitations, kriging has been used to develop coarse, preliminary predictions of bioavailable 87 Sr/ 86 Sr for hydrological (e.g., Varouchakis et al, 2012;Johnson et al, 2018) and anthropological and archeological applications (Frei and Frei, 2011;Copeland et al, 2016;Wang et al, 2018;Willmes et al, 2018;Adams et al, 2019). Published bedrock and volcanic tephra 87 Sr/ 86 Sr are abundant throughout the Andes (Mamani et al, 2008;Scott et al, 2018), but these samples are limited in various parts of the Peruvian Andes, which limits the accuracy of existing bedrock 87 Sr/ 86 Sr models (e.g., Schenk et al, 1999).…”

Analysing Sr isotopes in low‐Sr samples such as single insects with inductively coupled plasma tandem mass spectrometry using N2O as a reaction gas for in‐line Rb separation

“…Here we test a newly developed solution method for strontium (Sr) isotope analysis using inductively coupled plasma tandem mass spectrometry (ICP‐MS/MS), after the work of Bolea‐Fernandez et al for its suitability in assessing the provenance of very small quantities of biological material of biosecurity relevance. Based on the high spatial variation of 87 Sr/ 86 Sr in the geosphere and the fact that Sr is expected to be present in relatively high concentration in many biological tissues, Sr isotopes are recognised as powerful tracers of provenance . The geographic variability of bioavailable Sr isotope ratios is related to a combination of their inherent variation in different bedrock geologies and the Sr being from a variety of environmental and anthropogenic sources .…”