Biface

This Cotter Chert biface (MWAC 18) is an unprovenienced or replica archeological artifact used in scientific research conducted for the purpose of studying the effects of fire on archeological resources. This collaborative project, managed by the Midwest Archeological Center (MWAC) and the Joint Fire Science Program (JFSP), focused on the study of park-specific fire conditions and their associated impact on archeological resources at six National Park Service units.

A select group of twenty-seven artifacts was chosen to gather baseline information on post-burn artifact weathering, and a sample of eighteen unprovenienced artifacts was selected for an experimental study of artifact cleaning techniques to measure the permanence of fire-related impacts. The artifacts are a representative collection of different materials that are typical of the parks in the study.

During one particular experiment on March 18, 2007, some of the artifacts were exposed to a flanking fire during a controlled burn. Conditions on the day of the fire were 70 degrees Fahrenheit, 36% relative humidity, and a 2-7 mph wind speed from the south. The fuel was primarily grassland with an average fuel load of 4.4 tons/acre. The burn duration was 19 minutes and 35 seconds with an average plot cluster temperature of 238 degrees Fahrenheit and a plot cluster maximum temperature of 859 degrees Fahrenheit. Exposure to this type and duration of fire left a heavy combustive residue on the surface of this biface (MWAC 18).

This study has resulted in a better understanding of the relationship between wildland fire and impacts to archeological resources in the Midwest Region. The information generated will allow park managers to focus efforts on archeological resources threatened by fire and develop strategies to reduce or mitigate anticipated negative impacts.