A bioavailable strontium isoscape of Australia. Initial contribution

Strontium isotopes (87Sr/86Sr) are useful in the earth sciences (e.g. recognising geological provinces, studying geological processes) as well as in archaeological (e.g. informing on past human migrations), palaeontological/ecological (e.g. investigating extinct and extant taxa’s dietary range and migrations) and forensic (e.g. validating the origin of drinks and foodstuffs) sciences. Recently, Geoscience Australia and the University of Wollongong have teamed up to determine 87Sr/86Sr ratios in fluvial sediments selected mostly from the low-density National Geochemical Survey of Australia (NGSA; www.ga.gov.au/ngsa). Three regional projects were focussed on: inland southeastern, northern, and southwestern Australia, together covering over 2.5 million km2 of catchment area. Whilst results on total Sr isotopic analyses have been reported previously (Caritat et al. 2022, 2023, 2024), a pilot study targeting the isotopic composition of bioavailable (or labile) Sr was conducted in parallel and this dataset is released here. In contrast to the total Sr isotope analyses, which were conducted mostly on NGSA Bottom Outlet Sediments (BOS; taken on average from ~60-80 cm depth), the bioavailable Sr work used Top Outlet Sediments (TOS; taken from 0-10 cm depth) to make the results more relevant to soil-, plant- and animal-focused applications. Approximately 1 g of air-dried, coarse-sieved (

锶同位素(87Sr/86Sr)在地球科学（如识别地质省域、研究地质作用过程）、考古学（如揭示古人类迁徙历史）、古生物与生态学（如探究已灭绝和现存类群的食谱范围与迁徙规律）以及法医学（如验证饮品与食品的溯源）领域均具有重要应用价值。近期，澳大利亚地球科学局（Geoscience Australia）与伍伦贡大学（University of Wollongong）合作，对河流沉积物中的87Sr/86Sr比值开展测定，这些沉积物主要取自低密度覆盖的澳大利亚国家地球化学调查（National Geochemical Survey of Australia, NGSA; www.ga.gov.au/ngsa）采样体系。本次研究涵盖澳大利亚内陆东南部、北部及西南部三个区域项目，总覆盖流域面积超过250万平方千米。此前团队已发表过全量锶同位素分析的相关结果（Caritat等，2022、2023、2024），本次同步开展了针对生物可利用态（或易活化态）锶同位素组成的预试验研究，本数据集即为此预试验的研究成果并在此公开发布。与主要采用NGSA底部出口沉积物（Bottom Outlet Sediments, BOS; 平均采样深度约60~80 cm）开展的全量锶同位素分析不同，本次生物可利用态锶研究采用顶部出口沉积物（Top Outlet Sediments, TOS; 采样深度为0~10 cm），以使得研究结果更贴合土壤、植物及动物相关的应用场景。本次研究称取约1克经风干、粗筛（