The ceramic ecology of florida: compositional baselines for pottery provenance studies

Abstract

The success of pottery provenance studies is fundamentally dependent upon spatially patterned variation in the composition of exploited clay resources. Uniformity in clay composition within a region and recognizable differences between regions of interest are essential requirements for determining provenance, but these parameters are difficult to satisfy in study areas such as the coastal plain of the southeastern USA in which chemical and mineralogical variation tend toward continuous gradients. In an attempt to improve the reliability and validity of pottery provenance studies in the area, this research investigates compositional variation in raw clay samples from across Florida and southern Georgia through NAA (n=130) and petrographic analysis (n=99). The results indicate that fourteen distinct compositional regions can be differentiated, ranging from 50 km to 400 km in length. These regions dictate the direction and minimum distance a pottery vessel must have been transported in order to be recognized as nonlocal through compositional analysis. The validity of the proposed compositional regions is supported by previous case studies focused on assemblages from three of the regions. In each case, vessels were transported from other compositional regions more than 100 km away.

Sourcing Interaction Networks of the American Southeast: Neutron Activation Analysis of Swift Creek Complicated Stamped Pottery

“…Each pottery sample derives from a unique earthenware vessel, represented by one or more sherds or nearly complete containers. The pottery data were compared to NAA results of 130 clay samples from throughout the region (Wallis, Gilmore, et al 2015).…”

“…Patterned variation in the bulk chemistry of clays is discussed in detail elsewhere and only briefly summarized here (see Wallis, Gilmore, et al 2015). Based on NAA results, a maximum of 14 compositional regions can be identified, mostly between 100 km and 300 km in extent.…”

“…In both the number of samples and sampled sites, this is the largest NAA study ever completed in the American Southeast. The resulting data are further evaluated through comparison with 130 clay samples col-lected from throughout the region (Wallis, Gilmore, et al 2015). Future work will integrate data from ongoing petrographic analysis of the same pottery samples to further strengthen interpretations of provenance.…”

Comparative Clay Analysis and Curation for Archaeological Pottery Studies

“…In Florida, we have found that clays exhibit broad geographic patterns in mineral inclusions and bulk chemistry that are useful markers for pottery provenance studies (Wallis et al 2015). More than a dozen elements measured by NAA and mineral inclusions such as muscovite, calcareous matrix, phosphatic nodules, and siliceous microfossils observed in petrographic thin section show patterned distributions.…”

Social Networks and Networked Scholars

“…Our vessel lot table also includes summary data for NAA and petrographic analysis. Specifically, we have employed the groupings for these variables developed by Wallis and colleagues (Wallis et al 2015). At this time, we have retrieved NAA data for 512 sherds (representing an equal number of vessel lots) from our study area.…”