A Combined 87Sr/86Sr and δ18O Isoscape of Minnesota for Estimating Geographic Origins – A Case Study

Summary

This is an abstract from the "SAA 2024: Individual Abstracts" session, at the 89th annual meeting of the Society for American Archaeology.

Strontium and oxygen isotopes preserved within plant and animal remains reflect the regional geology and environment where they originated. This approach relies on a regional map of baseline isotope values – or isoscape – to link values preserved in remains with a region of origin. Mechanistic models, which estimate baseline 87Sr/86Sr based on age and type of bedrock, can be used for geographic origin estimates if the primary driver of 87Sr/86Sr comes from weathered bedrock. In post glacial landscapes such as Minnesota, which are mostly covered by till, mechanistic models based on bedrock cannot be reliably used to estimate geographic origin. This project developed an 87Sr/86Sr isoscape of Minnesota through vegetation sampling and combined this data with pre-existing δ18O isoscapes. Variability in δ18O is largely dependent on regional precipitation patterns, so the δ18O preserved in organic materials can be used to constrain geographic origin estimates. The combined 87Sr/86Sr and δ18O isoscape was evaluated on its ability to accurately estimate the geographic origin of archaeological faunal material of known provenance. This research demonstrates the necessity of developing regionalized isoscapes and outlines a protocol for doing so. It has produced a resource that has wide ranging applicability in archaeology and related fields.

This Resource is Part of the Following Collections

• SAA 2024: Individual Abstracts   •
• Society for American Archaeology 89th Annual Meeting, New Orleans, LA (2024)

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Record Identifiers

Abstract Id(s): 39427.0