Doctoral Dissertation Improvement Award: The Ecological Context of Modern Human Adaptability

xThis doctoral dissertation project investigates the ecological context of modern human evolution during the Late Quaternary. This is important because the key to understanding the evolution of behaviors characteristic of the human species, such as enhanced adaptive flexibility and the expansion of social interaction and exchange networks, among others, lies in tracking their trajectories through deep time. To date, archaeological evidence for adaptive flexibility comes mainly from sites dating to the latter half of the Middle Stone Age (MSA) from ca. 130,000 to 30,000 years ago.. However, the sites under study has several well-stratified MSA sequences that offer an excellent opportunity to track longer-term environmental changes and biocultural responses in a region central to the modern human evolution narrative. This work sets the context for further site-specific, high-resolution paleoenvironmental reconstructions and contributes knowledge on whether and how environmental changes precipitated innovation during the behavioral evolution of humans. It further assesses the connection between ranging patterns and environmental changes. The investigators also use the project to train interested students from local universities in archaeological field and lab methods. The project addresses questions as to whether site-level environmental reconstructions in the sites under consideration match local climatic and paleoenvironmental patterns recorded for the Late Quaternary. They are also determining if ranging patterns and degree of social connectivity differ during arid versus humid periods. Lastly, they are investigating whether lithic technological shifts through deep time suggest increasingly adept responses to environmental change. To achieve this, four MSA sites were excavated resulting in thousands of lithic artifacts. Various lithic technological attributes were recorded, and work is underway to develop a chronostratigraphic history of the region through chemical fingerprinting of the volcanic ashes and 40Ar/39Ar dating. This phase of the project is developing a high-resolution paleoenvironmental reconstruction using plant leaf waxes (δ13Cwax), bulk organic matter (δ13COM), and carbonate nodules, as well as at sourcing obsidian artifacts using a portable handheld X-ray fluorescence (pXRF) machine. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.