Dr. Eugene Smith of the University of Nevada, Las Vegas and Dr. Curtis Marean of Arizona State University will operate analytical laboratories that will apply a new dating method using ash erupted explosively from volcanoes to archaeological sites in South Africa and Europe. In South Africa, Marean and Smith will determine when a suite of uniquely human features first appeared in the evolutionary history and thus help understand when, where and why the human species evolved. South African Middle Stone Age (MSA) sites have revolutionized our knowledge of modern human origins by pushing back and enriching our knowledge of the timing of key features science considers definitive for the species. In Europe, using volcanic ash, the laboratories will precisely date the timing of when modern humans replaced Neanderthals. Modern dating techniques and their application to archaeological sites provide the basis for determining when key events in early human history occurred. These techniques use complex models that produce age estimates and not absolute dates. In the past, different laboratories have used different models that may result in different ages for the same geologic unit. This has created a dating controversy that reduces confidence in the timing of key events in early human history. There is general agreement that the best way of producing robust age estimates is to use several independent dating techniques. Recently, the team identified volcanic ash in three archaeological sites in southern Africa, and the best fit of the chemistry of this ash is to the 74,000-year-old eruption of the Toba volcano in Indonesia. This discovery provides an independent dating tool that can be used along with traditional dating methods to resolve the dating controversy and tie the record of human origins preserved in these sites in southern Africa to the global record of modern human origins. This project will not only provide a new independent dating tool for archaeological sites but will help train students and early career scientists in the techniques of archaeology and geology.
Drs. Smith and Marean and their research team will collect and process samples from archaeological sites in southern Africa and Europe to identify and determine the distribution of volcanic ash that may be used to precisely date major events in early human history and to tie early human history recorded at each of these sites to a single dating model. Precise dating using volcanic ash will remove any debate about the timing of key events in early human development. Correlation of volcanic ash to source volcanoes will be done using the chemistry of the ash. The ash is in the form of very small (micron-sized) glass grains known as shards. These grains are analyzed by instruments that focus a small-diameter electron or laser beam on the shard to determine their chemical makeup. The chemistry is then compared to a database of known chemistry to identify the source and age of the ash.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
