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High-Resolution Analysis of Unique Paleoenvironmental Data from Key Hominin Sites in East Africa

Horn of Africa

The possibility of a causative relationship between human evolution in Africa and Earth system history has been an important question at the forefront of paleoanthropological research in the last 25 years. We propose to analyze climate and other Earth system dynamics with a unique combination of paleoanthropologists and earth scientists to provide direct tests of this and related hypotheses by collecting and analyzing unique paleoenvironmental data at three key anthropological sites in Africa.

The possibility of a causative relationship between human evolution in Africa and Earth system history has been an important question at the forefront of paleoanthropological research in the last 25 years. One fundamental question is – can any of the Earth system drivers be characterized with sufficient precision to enable correlation with hominin evolution and their identification as evolutionary causal factors?

We propose to analyze climate and other Earth system dynamics with a unique combination of paleoanthropologists and earth scientists to provide direct tests of these various hypotheses by collecting and analyzing unique paleoenvironmental data at three key anthropological sites in Africa. We propose to collect continuous paleoenvironmental records by drilling long cores from ancient lake beds in the northern Afar, Ethiopia (~3.8-2.9 Ma), the Baringo Basin, Kenya (~3.2-2.35 Ma), and the Turkana Basin, Kenya (~2.3-1.42 Ma), and correlate these records to the outcrops in the same basins that contain hominin and other mammalian fossils, as well as artifacts in the younger time periods.

The sediment cores will provide high-resolution (centennial-millennial scale) paleoenvironmental records that can be correlated with previously collected fossils and artifacts from outcrops using tephrostratigraphy, paleomagnetism and other geochronological techniques. Geochemical analyses of these cores will supply relevant data about climate change utilizing TEX86 and clumped isotope paleothermometry, as well as other geochemical and lithologic archives that record various aspects of the paleoclimate system.

Geochemical analyses will be complemented by the paleoecological analyses of pollen, charcoal, diatoms, ostracodes and other biological materials that collectively provide a record of water resources (quantity and quality) and landscape resources and conditions (vegetation, fire) upon which local hominins would have relied. All of these records are subject to poor preservation in the outcrops where the actual hominin fossils and artifacts are recovered due to weathering, but can be continuously obtained in high quality conditions from drill cores.

We will use our high resolution paleoenvironmental data to test a series of overarching and basin-specific hypotheses linking climate, water and vegetation to resources in the mammalian (including the hominin) fossil record. The core paleoenvironmental data will be placed in a three-dimensional context using outcrop-based data in each region, enabling the relevant ecological data to be integrated with databases of the mammals and hominins for each region using abundant geochronological tie-points. These fossils have been previously placed into stratigraphic context such that we will be able to enter fine-grained climate, tectonic and seasonal data for each hominin, archaeological locality and spatially relevant mammals.

The individual databases will be combined into an East African regional database to compare both local and regional results with data available on overall global climate mechanisms from other sources such as marine records.

Finally, we will use these new, combined paleoenvironmental and paleoanthropological data sets, combined with agent-based modeling to better understand how landscape and climate change across temporal and spatial scales impacts the durability and predictability of critical ecosystem resources.

Funding Source:
National Science Foundation

Chris Campisano, Arizona State University School of Human Evolution and Social Change
Ramon Arrowsmith, Arizona State University School of Earth and Space Exploration
Kaye Reed, Arizona State University School of Human Evolution and Social Change
Asfawossen Asrat, University of Addis Ababa
Jonathan Wynn, University of South Florida
Alan Deino, Berkeley Geochronology Center
Anders Noren, University of Minnesota – Twin Cities
Andrew Cohen, University of Arizona
Craig Feibel, Rutgers, the State University of New Jersey
Erik Brown, University of Minnesota
Isla Castaneda, University of Massachusetts – Amherst Department of Geological Sciences
James Russell, Brown University
John Kingston, Emory University