Research

Our lab is currently pursuing a number of research projects with collaborators from around the world:

Food Globalization in Prehistory A large part of the world’s crops are cultivated in regions quite different from their place of origin. While much of that food globalization has resulted from modern trade networks established during the past 400 years, it has its roots in prehistory. By the beginning of the second millennium BC, the south-west Asian crops, notably, wheat and barley, were in several parts of China, and Chinese millets were in Europe. Meanwhile, there were parallel exchanges of staple crops between east and south Asia and between south Asia and north Africa. In the context of the European Research Council project, Food Globalization in Prehistory, we employ stable isotope studies, archaeobotany and archaeogenetics to establish when and how that early globalization of staple foodstuffs happened.
Additionally, we are beginning to quantify baseline carbon isotope (δ13C) values of millet seeds, which will be essential to interpreting past human and animal diets, particularly when archaeobotanical samples are limited. We plan to quantify the spatial and temporal variability in modern millet seed and leaf δ13C values by sampling millets from the Harlan collection housed at the University of Illinois. This millet δ13C baseline will open the door to sampling archaeological human and animal bones from an array of East African sites in an effort to identify early C4 plant use. This research is funded through a grant from the Washington University International Center for Advanced Renewable Energy (I-CARES).
 
Dietary revolution and the legacy of millet farmers in Central Asia during the second millennium BCBy the end of the second millennium BC, eastern Kazakhstan and western China had become the crossroads of Trans-Eurasian exchanges of material goods, metallurgy, domestic animals, and most importantly, staple grains. In the context of the long-distance translocation of cereal crops, this project draws upon contrasts in the isotopic signatures of the Fertile Crescent crops, including wheat and barley (C3 plants) compared to Asian millets (C4 plants) to investigate a number of key regions, including the Chinese province of Gansu, as well as northern and southern parts of Kazakhstan. Human and animal skeletal samples and plant remains were collected for isotopic analyses. This project has also relied on published isotopic data to consider whether millets spread from their putative domestication center in the East to western Eurasia. Preliminary results have revealed contrasting patterns in the East and in the West. In the West, the consumption of significant quantities of millet was both sporadic and delayed. In Gansu, however, the isotopic data indicate that a significant shift in staple foods from millets towards the Fertile Crescent crops happened within the first two centuries of the second millennium.
A key question emerging is ‘Was it people or plants on the move?’ In collaboration with the Institute of Vertebrate Paleontology and Paleoanthropology, the Chinese Academy of Sciences and the Max Planck Institute for Evolutionary Anthropology in Leipzig, this project is considering the human genetics legacy of the spread of agricultures across Asia.
 
The origins of narcotic-avoiding strategies on the Tibetan Plateau 2000-1000 BC
Up until now, most research into the prehistory of plant foods in China has been conducted with foci of cereal crops and the Neolithic farming communities. In recent years, that has been extended to plant use in pastoral/agricultural communities that lived on the highland Tibetan Plateau. This project shifts the focus to the problem of human ecology itself and the challenge of acquiring sufficient plant foods in the novel environments that the first generations of humans who settled the Tibetan Plateau. 

 

Holocene terrestrial climate variability in the Horn of Africa A period of amenable climate in North and East Africa, known as the African Humid Period (AHP), is thought to have lasted from about 11 to 5 thousand years ago, but the precise timing and pacing of both the initiation and conclusion the AHP is disputed. Very few climate records are available from the Horn of Africa, making it a region of particular interest. Together with Wash U Anthropology Professor, Dr. Fiona Marshall, we are investigating past changes in aridity in the Horn of Africa using the geochemistry of sub-fossil mammal tooth enamel obtained from a unique archaeological faunal assemblage from southern Somalia.