Experimental Burned Rock Studies on the Edwards Plateau: A View from Camp Bullis, Texas

Abstract

This article presents an experimental study concerning the use of thermally altered stone, commonly referred to as fire-cracked, or burned rock. A series of controlled cooking experiments were initiated as limestone cobbles were placed within a prepared earth-oven and re-heated; this type of earth-oven is similar to those found within prehistoric burned rock mounds on the Edwards Plateau of central Texas. Twelve experiments were conducted in this study, as four different sets of cobble assemblages were each re-heated three times, at six, twelve, twenty-four, and forty-eight hour intervals. These heated limestone cobbles were then analyzed for thermal alteration characteristics such as color change, cracking, and spalling, for comparative purposes. Quantitative analyses were then applied to the data in order to establish whether different patterns of thermal alteration exist dependent upon short-term and long-term re-uses.