The purpose of this project is to classify temper from different types of Caddo pottery sherds and determine sub-categories that exist, if any. The pottery sherds are from the Bowman site (ca. A.D. 1100-1500) located on the Red River in southwestern Arkansas and were initially classified based on physical appearance using a light microscope. The sherds were divided into categories based on temper: bone, clay, shell and grog. Early Caddo potters used only clay (or a lack of temper), whereas later production included the addition of bone, shell, or grog (ground, previously fired clay) in order to strengthen the pottery. The next step in the project used a scanning electron microscope with an energy dispersive x-ray spectrometer (SEM-EDS) to analyze the pottery sherds in an attempt to verify or modify previous light microscope temper classifications. The SEM-EDS helped determine which elements are present in addition to atom and weight percentages for each element detected. The pottery sherds are electrically non-conductive, so they were first sputter coated with gold. All of the samples contained carbon, oxygen, magnesium, aluminum, potassium, and silicon. SEM-EDS data indicated the bone-tempered pottery samples contained additional phosphorus and calcium, while the shell tempered samples contained only additional calcium (as compared to the clay pieces). Future work will involve the analysis of the clay and bone categories since the light microscope and the SEM-EDS suggested noncorresponding classification of these pieces.

Classification of Caddo pottery sherds using SEM-EDS

2019 Spring National Meeting

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