The drill cores were then shipped to the National Lacustrine Core Facility (LacCore) at the University of Minnesota. Colleagues in the National Museum of Natural History’s Human Origins Program and Department of Paleobiology and dozens of collaborators at institutions worldwide worked to analyze the environmental record they had obtained, which is now the most precisely dated African environmental record of the past 1 million years. Charting radioisotope ages and changes in chemical composition and deposits left by plants and microscopic organisms through the different layers of the core, the team reconstructed key features of the ancient landscape and climate across time.
They found that after a long period of stability, the environment in this part of Africa became more variable around 400,000 years ago, when tectonic activity fragmented the landscape. By integrating information from the drill core with knowledge gleaned from fossils and archeological artifacts, they determined that the entire ecosystem evolved in response.