Sample selection for ceramic use-alteration analysis: The effects of abrasion on soot

Ceramic use-alteration analysis is a useful approach to determine vessel function. however, some forms of post-use alteration hinder analysis from recognizing use alteration and/or selecting appropriate samples for analysis. This paper illustrates how, through replication and experimental work, researchers can determine which pieces are relatively unaffected by post-use processes and should have preserved use alteration. The case study here considers the effects of one post-use process (abrasion) on one kind of use alteration (sooting) on one type of material (low-fired, fibre-tempered ceramic vessels broken into sherds). Fragmentation and nonuse alteration of vessel and sherd surfaces are problems particularly for Late Archaic (5000-3000 BP) fibre-tempered ceramic assemblages from the Southeast and Midwest United States. First, the identification of soot on fibre-tempered sherds from three Archaic sites in Georgia is described. Manufacturing method and firing temperatures for Archaic vessels were then determined, and this information was used to produce test tiles and vessels for use in abrasion experiments. Test tiles and sooted sherds were abraded with water and gravel for different periods of time to observe soot removal. Guidelines for sample selection of fiber-tempered sherds for use-alteration analysis are based on these experimental observations.