95 Archaeological Geology (Posters)

Monday, 10 October 2011
9:00 AM - 6:00 PM
Hall C

UTILIZING GEOCHEMISTRY TO STUDY COMMUNITY STRUCTURE AT A MIDDLE WOODLAND VILLAGE IN THE LOWER WABASH VALLEY, INDIANA

Paper number: 95-5
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

The community structure of Middle Woodland sites in the lower Wabash River Valley has been debated for more than four decades. Geophysical survey (magnetometer and GPR) conducted at the Allison-LaMotte Northwood site (12Vi 194) in west central Indiana suggests a formally organized village pattern consisting of a residential zone surrounding a plaza. Subsequent test excavations were designed to ground truth the geophysical data. This presentation focuses on the soil geochemistry of pit, midden, and proposed plaza samples, which are used to test the spatial pattern observed in the geophysical data.

Phosphorus and organic carbon were examined as indicators of patterns of refuse disposal within the site. Eighteen residential zone soil samples, six plaza zone samples, and one off-site sample were analyzed for phosphorus and organic carbon. We employed four steps of the SEDEX sequential phosphorus extraction method to decipher phosphorus content in the soil samples. Random duplicates and standard samples were also run to ensure data quality. Organic carbon was examined using a coulometer with each sample analyzed in triplicate for data accuracy. Both phosphorus and organic carbon data reveal drastic differences between plaza and residential zone soil geochemistry lending support to the spatial patterns recognized in the geophysical data.