Fluvial Sherd Abrasion and the Interpretation of Surface Remains on Southwestern Bajadas

Abstract

Sherds abraded by fluvial processes are frequently encountered during archaeological surveys, but are most often ignored or misinterpreted. Analysis of sherds within the Ruelas drainage in southern Arizona, and experimental replication of fluvial abrasion, demonstrate how these data can be used in the study of prehistoric land use and settlement location. Under simulated conditions of fluvial transport, sherds are found to abrade in a three-stage sequence. The sherds collected along the Ruelas drainage are placed into the stages of abrasion and a progression of abrasion with increasing distance from the mountains is demonstrated. The origins of these sherds are attributed to sites located farther upstream rather than along the mid-bajada banks of the Ruelas drainage. Experimentation with fluvial sherd abrasion also permits specification of the attributes of transported sherds, contributing to proper field and laboratory identification and thus more accurate inferences about the post-depositional history of surface remains.