Multi-Isotopic Investigation of Population Dynamics and Mobility among Rural Medieval Christian Communities at Ghazali, Northern Sudan

The archaeological site of Ghazali (northern Sudan) provides a rare opportunity to investigate the dynamics of mixed economies and mobility on the fringes on the Nile valley at the time of Christian expansion in Nubia. Thanks to its particular hydrological conditions, Sudan has a long history of diverse groups pursuing different economic activities, with agricultural communities settled along the fertile Nile valley and various mobile pastoralists groups occupying vast areas of the adjacent deserts. Ghazali represents an early medieval Nubian rural site with an extensive funerary zone. Somewhat removed from the Nile valley, Ghazali extends along the western bank of a large wadi, Wadi Abu Dom, running across the Bayuda desert, dated ca. 7th–13th century CE. Multi-isotopic analysis of human tooth enamel from Cemeteries 1, 3, and 4 was used to explore patterns of mobility among these communities. Ten enamel samples were subjected to 87Sr/86Sr analysis, while 24 individuals were studied for their δ18O values. 87Sr/86Sr and δ18O values were very heterogeneous, suggesting that the Ghazali community, as a whole, benefited from a variety of water sources, perhaps including significant contributions from groundwater wells. We suggest that this adds further support for the reconstruction of a mixed practice of agriculture and animal herding in the neighbouring Bayuda desert. These data add to growing evidence for diverse and flexible mixed economies in eastern Africa that provided food security even under the most challenging of conditions.