Understanding environmental impacts of prehistoric fire

Through intentional and unintentional landscape burning, humans have an impact on local and regional fire ecologies. Modern and historical accounts document humans use of fire as a hunting or farming aid. Looking back further in human history, there is archaeological evidence for widespread fire use reliably dated to 350,000 years ago and growing evidence for at least sporadic use dating back at least 1.6 million years ago. However, limited archaeological evidence for fire use makes it difficult to understand the relationships between human fire use and fire regimes, landscape scale vegetation changes, and possible feedback loops created by these interactions. Here we first present a framework for investigating fire in deep time and for understanding how human fire use impacted ancient landscapes. Our framework combines several lines of empirical evidence (geochemistry, geomorphology, paleobotany, paleomagnetism, and traditional archaeological analysis). We explore the presence or absence of fire at archaeological sites and combine this with modeling to better understand how and when humans began interacting with fire. Second, we present as a case study, data gathered from a ~1.6 million year old archeological site (FxJj20 AB) in the Turkana Basin in northern Kenya that show hominins may have used fire at this location. Our future work will expand the investigation from this single site to include several archeological and non-archeological sites over space and time to understand when humans began using fire. The local site records of fire activity will be placed in a broader regional, long-term framework of climate, vegetation, and fire at a broader scale using the adjacent, continuous lake core (HSPDP WTK13). This will allow us to more precisely evaluate early human impacts on the fire regime in the Turkana Basin. .