A Provisional Theory of Ceramic Abrasion (original) (raw)

1989, American Anthropologist

This article calls attention to ceramic abrasion as a class of traces that can be employed by the archeologist in a variety of behavioral studies. Basic principles of ceramic abrasion are set forth, built upon the engineering literature and on experiments undertaken in the Laboratory of Traditional Technology. Abrasion mechanism are discussed, but the limitations of current knowledge are underscored. The major factors pertaining to ceramic, abrader, and contact situations that in$uence the rate and nature of abrasion are identajed. MAJOR TREND I N ARCHEOLOGICAL ANALYSIS during the past several decades has A been the recognition and exploitation of new lines of evidence for inferring past human behavior and environmental conditions. Experimentation often plays a crucial role in validating new lines of evidence; recall, for example, the many hundreds of experiments required to establish the relationships between lithic polish types and worked materials (Keeley 1980; Vaughan 1985). This article calls attention to ceramic abrasion, a family of common traces that so far has been little studied. In order to lay a foundation for the use of these traces in inference, we have been investigating ceramic abrasion experimentally. Building upon our experimental results and recent studies in engineering, this article proposes a provisional theory of ceramic abrasion. Knowledge of the factors influencing abrasion rates and the formation of abrasion traces can contribute to three areas of archeological inquiry. First, an understanding of the technical choices that influence abrasion resistance, such as firing temperature and surface treatment, can help investigators to determine if-and how-pots in specific technological traditions were designed for good abrasion resistance. Second, abrasions or scratches comprise an abundant type of wear; thus, an appreciation for the conditions that cause abrasive wear and the factors that lead to differences in abrasion patterns can enhance ceramic use-wear analysis (cf. Bray 1982; Griffiths 1978; Hally 1983; Schiffer 1989). Third, because a host of processes from trampling to fluvial transport abrade ceramics, an experimentally grounded theory of abrasion can contribute to fine-grained identification of formation processes (cf. Schiffer 1987). Basic Concepts and Principles Abrasions and Abrasive Processes Two interrelated phenomena are of interest here: (1) abrasions, as a category of traces, and (2) abrasive processes, the activities of people and nature that produce abrasions. For present purposes, an abrasion is defined broadly as a trace that was formed by removal or deformation of material on a ceramic's surface by mechanical contact, specifically, the sliding, scraping, or, in some cases, striking action of an abrader (i.e., a particle, object, or surface). The abrader can also include particles entrained in a fluid such