Thin-section analysis of temper in patayan ceramics from Willow Beach, Arizona.

Abstract

Prehistoric ceramics along the Lower Colorado River have been difficult to classify, partially due to their lack of decoration. These utilitarian, plain brown wares are best described by the materials used to manufacture them. Five sherds of Patayan ceramics (A.D. 900 -1150) recovered from Willow Beach, Arizona are examined in thin section. Based on a preliminary examination of surface treatment, color, and temper by another investigator, these five sherds are thought to represent five subgroups of ceramics from the site. Temper is the non-plastic, granular material potters add to clay to prevent a ceramic vessel from excessive shrinking during drying or firing. In this study, a petrographic microscope is used to examine the temper found in one sherd from each of the five subgroups. A thin-section analysis of temper on the five sherds reveals that raw materials used to produce the ceramics were derived from the garnetiferous granite pegmatite outcropping at the site. Furtherrnore, it is shown that there is no difference in temper used in the five sherds. Therefore, the five sherds do not represent separate subgroups if temper is the sole criterion of analysis.