Quantifying shell weight loss in archaeological deposits

Abstract

ABSTRACT While a range of physical and chemical taphonomic processes are known to affect archaeological shell assemblages, it has been difficult to directly quantify the effects of these degradational processes on the shell itself. Here the measurements of Anadara granosa shell features are used to derive morphometric equations for estimating expected shell weights. A cubic regression model is developed to this end, based on measurements of all shell elements of complete A. granosa valves, resulting in high predictive power. The morphometric method proposed here therefore allows for the comparison of observed and expected shell weights to determine the extent of weight loss as an indication of these processes. A case study is presented by applying these morphometric equations to a midden assemblage from northeast Arnhem Land to investigate potential bias in shell preservation. This study demonstrates the efficacy of the proposed method, and the need to assess the interaction of different taphonomic processes on a site and species‐specific basis.