Interpretation of past hominin and animal mobility over large-scale distances near Oldupai Gorge is possible, shows new study
A recent publication in the Journal of Archaeological Science provides landscape-scale strontium isotope data and a proof of concept using animal teeth associated with major palaeoanthropological findings, showing that animal migrants coming far from the Oldupai Gorge region can be identified. This has major implications for the study of past hominin mobility in this important part of East Africa.
Strontium isotope analysis has been used for directly studying the mobility of past people and animals. While sampling ancient teeth has proven a valuable research method in the archaeological field, it has rarely been applied to ancient hominin remains, particularly in the traditional evolutionary cradle of East Africa. To be successfully employed, it is essential that archaeologists have a good understanding of how strontium isotopes vary across a landscape, and how they travel from underlying rocks, into plants, and the diets of different animals, including hominins.
Proving proof of concept
This new paper, an international collaboration by researchers from the University of Calgary, the University of Dar es Salaam, the Tropical Pesticides Research Institute, and the Max Planck Institute for the Science of Human History, provides the first landscape-scale strontium isotope values using modern plants to produce a map depicting strontium variation in the Oldupai Gorge locality. The results demonstrate strontium values to be largely homogeneous in the region. As a result, hominins and animals coming from far away yield different strontium values from the study area and will be easily recognizable as incomers.
The authors also provide strontium isotope values from archaeological animal teeth unearthed at Engaji Nanyori, a site dating to approximately 1.1 to 0.6 Ma, as a proof of concept study. Diagenetic strontium was successfully removed from the teeth, proving that strontium isotope analysis can be used successfully on deep time dental remains from the region.
The significance of Oldupai Gorge
Oldupai Gorge is a world-renowned palaeoanthropological and archaeological site complex in Tanzania’s Ngorongoro Conservation Area, bordering Serengeti National Park. The Gorge yields stone tools and skeletal remains of hominins and animals from the last two million years.
Notably, the various Oldupai Beds (I-IV, Masek, Ndutu, and Naisiusiu) contain stone tools made for multiple industries and skeletal remains of a number of highly significant hominin species: Paranthropus boisei, Homo habilis, Homo erectus, and Homo sapiens. The application of strontium isotope analysis in this crucial area for human evolution research will open up exciting new opportunities for studies of past human and hominin land use, mobility, and social connectivity in the past. The authors encourage other researchers to use and to build on their landscape strontium results to explore these topics.