Under the guidance of Dr. Sally McBrearty, David Leslie will analyze fossil soil organic carbon, soil carbonates, and animal tooth enamel for stable isotopic values useful for environmental reconstructions. These fossil indicators were collected during the field seasons of 2011 and 2012 in the Lake Baringo basin, Kenya, where a geologic formation, the Kapthurin Formation, preserves sediments that date to 545 - 235 thousand years ago, during the Middle Pleistocene. The Kapthurin Formation preserves archaeological evidence for the transition from the Acheulian to the Middle Stone Age, a time period that marks significant technological change and culminates with the emergence of our own species, Homo sapiens. Mr. Leslie's research will focus on reconstructing environments during this time period, while also developing a novel technique to link the biomass productivity of modern environments with stable isotopic indicators from modern soil organic carbon and carbonates using computerized remote sensing and geography information systems. This technique offers a new environmental proxy to use when reconstructing past environments, and is broadly applicable to other time periods and archaeological and paleontological sites.
It is widely accepted that changes in environments can affect species diversity and speciation. During the Middle Pleistocene of East Africa, significant biological and technological change occurred and could be driven by changing environments. This project will reconstruct two separate landscapes, dating to 545 - 509 and 509 - 235 thousand years ago, available to Acheulian and Middle Stone Age human ancestors, to discern any differences or similarities in the use of landscapes, environments, resources, and technology. Stable isotope values will be derived from 720 samples of modern and fossil soil organic carbon, carbonates, and animal tooth enamel to reconstruct these environments. Ultimately this research seeks to test the effect of environmental change on technological and biological changes during the Middle Pleistocene of East Africa and the accuracy of continental models of climate change in relation to the Lake Baringo basin.
This research will highlight the importance of using multiple lines of evidence when reconstructing environments to arrive at the best approximation of past environments. Preliminary research was conducted with the help of Kenyan colleagues during the summers of 2011 and 2012, and was supported in part by grants to Dr. McBrearty from the National Science Foundation (BCS 0917965) and grants to Dr. McBrearty and Mr. Leslie from the University of Connecticut. The results of this research will be shared with colleagues through conference presentations, lectures, and peer-reviewed publications. The raw data created from this project will be made available via an online data repository, thereby making it accessible to the public. In the future, Mr. Leslie plans to incorporate remote sensing and geography and information systems methods developed, as well as stable isotope extraction and analysis techniques, into hands-on laboratory classes for undergraduates.
