The Impact of Grassland Fires on the Archaeological Record—A Case Study Along the Eastern Escarpment of the Southern High Plains of Texas

Fires are an essential aspect of the grassland ecosystem across the Great Plains of North America. Wildfires can also transform surrounding rocks to appear like hearths or hearthstones used by prehistoric people. A grassland fire that swept through part of a historic ranch located along the eastern escarpment of the Southern High Plains of Texas has created surface features that mimicked the appearance of hearths. Fourteen wildfire features resembling hearths have been documented, and thermally modified rocks from the surface of three of these features were analyzed to investigate the impact of natural fires on the landscape. The results demonstrate that wildfires can create features resembling hearths when an adjacent shrub is burned. An excavation and detailed analysis, however, suggest that (1) the tops of thermally modified rocks from a wildfire will often have a relatively darker Munsell color value in comparison to their bottom halves, and (2) wildfire features will likely have a thinner cross-section of ash and larger pieces of charcoal produced from the incomplete combustion of the nearby shrub and deadfall. The broader implications are useful for understanding site formation processes within temperate grassland settings in other places.