The palaeoenvironmental potential of bioarchaeological isotope data

Abstract

Bioarchaeology not only provides insights into human, animal, and environmental ecology, but also generates huge amounts of stable and radiogenic isotope data that are not well recognised by other disciplines. Here, we present potential avenues for the integration and interpretation of archaeological isotope data into environmental studies. We emphasise the large spatio-temporal scales on which isotope patterns can be observed, for example using isoscapes, the limitations and potential pitfalls that come with isotope data from archaeological research, and future cross-disciplinary collaborations between bioarchaeology and other palaeo-disciplines.

Keywords: Element cycles; Environmental monitoring; Geochemistry.

Fig. 1. Characteristics of bioarchaeological and environmental proxy archives.

The bioarchaeological samples are (from left to right): hair, nail, tooth, bones with short or long turnover rates, bones from young animals/individuals, and charred grains. The temporal depth varies between proxies, yet the palaeontology and bioarchaeology hardly provide any continuous time series and the bioarchaeological sample frequency is considerably reduced towards the oldest samples. The dating uncertainty or precision can reach one calendar year for tree-rings, speleothems, varved lake’s sediments, speleothems, young ice cores, corals and molluscs, but it can be decadal to millennial for most proxies depending on the temporal depth and the datation method. The proxy resolution varies from sub-annual to decadal for most proxies, it can be (multi-)centennial for marine sediments and other layers that form slowly. The global spatial distribution vary between proxies: ice cores depend on global glacier distribution (light blue signature; source: https://wgms.ch/downloads/DOI-WGMS-FoG-2025-02b.zip); speleothems depend on karst regions (light brown signature; source: https://download.bgr.de/bgr/grundwasser/whymap/shp/WHYMAP_WOKAM_v1.zip); corals are restricted to tropical areas (dark blue signature; source: https://databasin.org/datasets/b983863c0a1a41e8839383b40ade437d/); molluscs are restricted to water bodies or archaeological sites, marine and lakes sediments originate from the respective water bodies, tree-rings depend on past forest covers and to some extent on archaeological sites (green signature: global tree ring record distribution; source: https://gis.ncdc.noaa.gov/kml/paleo_tree.kmz, last data access: 06th June 2025), palaeontological and bioarchaeological samples have a global extent but depend on past human activities, excavated sites and preservation conditions. The spatial scale reflected by each proxy goes from the local to the global scale, but even local proxies may inform about supra-regional processes when considered altogether. These characteristics are summarised in Supplementary Table 1. Figure © Michael Kempf 2025.

Fig. 2. Scale dependency of ecological functionality.

The upper panel shows decreasing climatic and ecological scales from GCMs (Global Climate Models) to supraregional ecozones, regional habitats, and local and micro niches (realised niches). The lower panel shows increasing spatial operations, including small-scale fragmentation, simplification such as regional aggregation and binning, and estimation processes such as interpolation. Figure © Michael Kempf 2025.