Impact of Prehistoric Cooking on Proxy Signatures in Shell Midden Constituents

Summary

The analysis of geochemical proxies in skeletal remains has become a standard tool in shell midden research. Sub-seasonally resolved proxy records provide information about environmental and anthropological aspects such as ancient climate conditions, fishing and foraging seasonality or site occupation pattern. However, as subsistence was the primary purpose for fishing activities in most prehistoric cultures, it is likely that many shell midden constituents were subjected to processing methods such as cooking prior to deposition, potentially altering their geochemical proxy records. To study the impact of prehistoric cooking methods on such proxy records, we exposed modern bivalve shells (Mercenaria campechiensis) to different prehistoric cooking treatments. Afterwards, we analyzed shell mineralogy, conventional oxygen and carbon isotopes, various element/Ca ratios and their clumped isotopic composition. Our data clearly show that all prehistoric cooking methods cause an alteration of most paleoenvironmental proxies and in particular the oxygen and clumped isotopic signatures even without a conversion of the initial aragonite into secondary calcite. Thus, depending on the cooking method, pre-depositional heating might have introduced considerable errors into previous paleoclimate studies using shell midden constituents. Furthermore our data show that clumped isotopes can be used to clearly detect and differentiate between different cooking methods.

This Resource is Part of the Following Collections

• Insights from Increments: Advances in Geochemical and Microscopic Analyses of Hard Tissues   •
• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)

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Record Identifiers

Abstract Id(s): 14849