This project will collect and analyze lake sediment drill core records from key localities in Kenya and Ethiopia to vastly improve our understanding of the paleoenvironmental and paleoclimatic context of human evolution. Understanding the relationship between climate/environmental history and human evolution is an enduring challenge of broad scientific and public interest. Key questions include: How did climate and tectonic change interact during critical intervals of human evolution? What processes regulated this history on local to regional scales? Do local records of climate change reflect global changes? How and when did climatic and tectonic processes combine to influence early human habitats, resources, and demography? Were these changing conditions related to evolutionary processes and events in the human lineage? Research on this relationship cuts across Earth, environmental and anthropological sciences. The sediment drill cores we will collect from lake deposits will provide detailed and highly resolved records of environmental history. Through data collection and modeling we aim to fundamentally transform the debate concerning how environmental dynamics at global, regional and local scales may have shaped human evolutionary history.
The project will obtain continuous paleoenvironmental records by drilling long cores from five high-priority areas in Ethiopia (N. Awash River and Chew Bahir areas) and Kenya (W. Turkana, Tugen Hills and southern Kenya Rift/Lake Magadi) where highly-resolved, continuous lacustrine paleoclimate records can be collected through important time intervals in the same basins that contain fossils and artifacts. Rather than assume a linkage between environmental history and evolution, we designed this study as a series of data collection and modeling exercises to explicitly test overarching and local hypotheses about environmental and evolutionary dynamics. Our high-resolution (centennial-millennial scale) and datable geochemical, paleoecological and sedimentological records will allow quantitative reconstruction of paleoprecipitation, paleotemperature, paleohydrology and geomorphic evolution at a regional scale. We will correlate these records using high-resolution tephrostratigraphy, magnetostratigraphy and other geochronological techniques to adjacent exposures that contain hominin and other vertebrate fossils, and artifacts, as well as to nearby marine records. We will develop predictive numerical models of environmental change and ecosystem response during critical intervals of human evolution and evaluate these models against our new, high-resolution records. These experiments will examine how landscape and climate change across a hierarchy of temporal and spatial scales impacts the durability and predictability of critical ecosystem resources. They will allow us to evaluate the importance of climatic thresholds and abrupt environmental changes and better understand the earth system dynamics that might have shaped the record of human evolution. Our modeling will generate new, testable hypotheses of human evolution/Earth system dynamics, including possible feedbacks from evolving hominin populations to their environments. Our project will create a key data set for addressing fundamental, existential questions for humanity. We will provide training and internship opportunities for 16 American graduate students, 2 post-docs and 10 undergraduates, and numerous training opportunities for African student and professional participants during the field and initial core description phase of the project. We have also planned significant investment in informal education, through a 3-D video project and outreach activities we will coordinate with our three museum partners (Smithsonian Institution, National Museums of Kenya and Ethiopia), both during and following the drilling phase.
