Stable Isotope Analysis Combined With ZooMS Reveals the Subsistence Strategies at Wupu Cemetery in the Eastern Tianshan Mountains, Northwest China

Abstract

During the 2nd millennium bce, domestic ruminants were introduced to the eastern Tianshan Mountains (ETM) of Xinjiang, China, leading to the emergence of settled pastoralism and agro-pastoral economy. Since around the early Iron Age (1000 bce), the nomadic pastoral culture arose in this area. However, how this process influenced the diet of ancient people in the transitional period during the Bronze–Iron Age, and the resilience to adapt to different natural environments still needs further study. In this study, carbon and nitrogen stable isotope analyses are performed on human hairs (n = 18), wools (n = 6), leathers (n = 3), and millet seeds (n = 5) from Wupu cemetery, dating to 3000–2400 cal BP in Hami basin, ETM. Three leather samples are identified as sheep or cattle by zooarchaeology by mass spectrometry. The δ¹³C divergence between wool samples (−20.0 ± 1.3‰) and cattle leather (−15.3‰ and −9.6‰) suggests a compound feeding strategy of sheep grazing in the natural environment and cattle raising in pens. The result of human hairs (δ¹³C = −16.7 ± 1.6‰, δ¹⁵N = 12.3 ± 1.6‰) indicates a subsistence strategy of C₃/C₄ mixed agriculture integrated with pastoralism at Wupu. Then, we collected δ¹⁵N values of domestic herbivores (n = 120) at low and high altitudes in the ETM as baselines to calculate human-herbivore δ¹⁵N offsets at different altitudes. The results show that a certain percentage of individuals with an offset value below 3‰ are present in all low-altitude sites dominated by agro-pastoralism. However, in the high-altitude sites dominated by nomadic pastoralism, there are no such individuals. Thus, human-herbivore δ¹⁵N offset values may have great potential to differentiate different lifestyles in the Eurasia steppe, where herbivores are the dominant domestic animals.