Chronology of a Fortified Mississippian Village in the Central Illinois River Valley

Abstract

Geophysical survey and excavations from 2010–2016 at Lawrenz Gun Club (11CS4), a late pre-Columbian village located in the central Illinois River valley in Illinois, identified 10 mounds, a central plaza, and dozens of structures enclosed within a stout 10 hectare bastioned palisade. Nineteen radiocarbon (14C) measurements were taken from single entities of wood charcoal, short-lived plants, and animal bones. A site chronology has been constructed using a Bayesian approach that considers the stratigraphic contexts and feature formation processes. The village was host to hundreds of years of continuous human activity during the Mississippi Period. Mississippian activity at the site is estimated to have begun incal AD 990–1165 (95% probability), ended incal AD 1295–1450 (95% probability), and lasted150–420 yr (95% probability)in the primary Bayesian model with similar results obtained in two alternative models. The palisade is estimated to have been constructed incal AD 1150–1230 (95% probability)and was continuously repaired and rebuilt for15–125 yr (95% probability), probably for40–85 yr (68% probability). Comparison to other studies demonstrates that the bastioned palisade at Lawrenz was one of the earliest constructed in the midcontinental United States.

Chronology for Mississippian and Oneota Occupations at Aztalan and the Lake Koshkonong Locality

“…In this article, we present new radiocarbon results and use Bayesian chronological modeling incorporating the radiocarbon data to suggest a settlement history for the Late Woodland and Mississippian presence at Aztalan and the Oneota presence at Lake Koshkonong. This work corresponds to several recent studies that have used Bayesian techniques to provide high-precision chronologies for archaeological sites in the North American midcontinent (Emerson et al 2019; Krus et al 2015, 2019). More broadly, this follows archaeological work abroad that applies Bayesian techniques to establish probabilistic chronological frameworks for the timing and duration of individual archaeological occupations and regions (Bayliss 2015; Hamilton and Krus 2018).…”

“…Additionally, numerous Effigy Mound and collared-ware Late Woodland sites were occupied within that same 25 km catchment (Goldstein 1991; Richards and Jeske 2002). The act of building a bastioned palisade at Aztalan must have been quite novel in precolumbian communities at the start of the second millennium AD, and this modeling reconfirms that Aztalan's palisade is the earliest known with bastions in the Mississippian world (Keeley et al 2007; Krus et al 2019). Specifically, modeling from this study estimates that the palisade at Aztalan was constructed in cal AD 1040–1160 ( 95% probability ; Figure 3; Table 1), probably in cal AD 1050–1125 ( 68% probability ).…”

“…The A model agreement values are greater than 60 for all of the models presented in this article, suggesting good overall agreement between the radiocarbon dates and the assumptions of the models (Supplemental Text 1). It should be noted, however, that OxCal's Charcoal Outlier algorithm iteratively downweighs the impact of wayward results until the model runs freely and consistently, irrespective of the overlap integral between the posterior results and standardized likelihoods (i.e., the agreement; Bronk Ramsey 2009b; Dee and Bronk Ramsey 2014; Krus et al 2019).…”

“…Previous Bayesian chronological work presented by Krus (2016) suggested that the Aztalan palisade is the oldest with bastions in the Mississippian world, possibly all of North America (Keeley et al 2007; Krus et al 2019). Palisades with bastions provide evidence for the militarization of Mississippian settlements, in part due to the strategic placement of bastions at regular intervals to shield the visibility of archers and to increase their line of sight (Keeley 1996:56).…”

Coalescence and Defensive Communities: Insights from an Andean Hillfort Town

“…For instance, one could point to elaborate social hierarchies in the great palisaded Mississippian chiefly centres or the walled cities of Early Dynastic Mesopotamia. The concept of coalescence does not seem as apt for such sites, where site location favoured proximity to rivers and agricultural land rather than defensibility, and defensive walls were typically added later in response to escalating hostilities (Krus 2013; see discussion in Gat 2002). In other words, defence did not condition social and architectural patterns as strongly at the outset.…”