http://tinyurl.com/c4oaxjz Shell from fresh- and saltwater mussels was used throughout prehistory in eastern North America. Religious or ceremonial iconography was depicted on shell gorgets and necklaces, crushed shell was used as an additive for ceramics, and beads were fashioned from drilled fragments of shell, to name but a few uses. Hypotheses regarding the provenance—or source—of these shell artifacts have often relied on assumptions based on the modern distribution of taxa and the nearest potential source. Activation analysis of shell to determine its chemical makeup has the potential to evaluate some of these hypotheses in a manner that is un-influenced by preconceived notions of cultural influence or recent changes in the geographic range of taxa. Samples of pre-Columbian shell from archaeological deposits across the eastern U.S. are analyzed. Statistical evaluations of their compositions results in the creation of compositional groups that reflect factors of habitat and geology. Results of this study suggest that activation analysis of shell for determining provenance may provide archaeologists with a novel and exciting tool for reconstructing cultural interaction.

1. Matthew T. Boulanger
Archaeometry Laboratory, Missouri University Research Reactor
Department of Anthropology, University of Missouri
Modern Trends in Activation Analysis 13
March 13-18, 2011
Texas A&M University

3.  Is there a significant difference in shell
composition from different regions such that
the provenance postulate applies?
 Are the mean shell compositions reported by
Cogswell et al. (1998) for correcting the
diluting effect of shell in a ceramic body
applicable to all shell-tempered pottery?
 Nac = Nau−((2.5 × Ca) ÷ 1000000) × 1488) ÷ (1−(2.5 × Ca) ÷ 1000000)
 Mnc = (Mnu−((2.5 × Ca) ÷ 1000000) × 578) ÷ (1−(2.5 × Ca) ÷ 1000000)

4.  From prehistoric contexts to avoid potential
effects of pollution and land-use changes
(e.g., increased sediment load resulting from
deforestation)
 Three genera are represented: Mya,
Crassostrea, and Mercenaria.
 Data for modern riverine mussels are drawn
from Cogswell et al. (1998).
 Specimen preparation and analysis follows
protocol outlined by Glascock (1992).

8.  Crassostrea shells tend
to be enriched in
transition metals
relative to Mercenaria
and Mya
Differences among genera

9.  Mya shells tend to be
enriched in REEs
relative to Crassostrea
and Mercenaria
Differences among genera

12. Freshwater Saltwater
 Na 1488 ± 100 ppm  3838 ± 702 ppm
 Mn 579 ± 72 ppm  25 ± 23 ppm
 Sr 104 ± 11 ppm  1583 ± 401 ppm
Cogswell et al. (1998) This study

13.  Shell chemistry may be useful for provenance
research—but further study is needed.
 Some chemical differences observed among
different taxa
 Saltwater and freshwater shell differ markedly
in composition.
 Formula offered by Cogswell et al. (1998) to
adjust compositions of shell-tempered
pottery are inappropriate for ceramic vessels
tempered with marine shell.

14.  Arthur Spiess (Maine Historic Preservation
Commission) and Neill Wallis (Florida Museum
of Natural History) provided the shell
samples.
 The MURR Archaeometry Laboratory is
supported by a grant from the National
Science Foundation (0802757).