Antiquity | Human Bone Isotope Study Provides New Evidence for Reconstructing Interaction Networks of Silk Road Oasis Populations
Recently, the Center for Archaeological Sciences, Sichuan University, in collaboration with several research institutions, published their latest research findings titled “Illuminating interaction networks along the Silk Roads: a multi-isotopic analysis of the Zaghunluq Cemetery, southern Xinjiang, China” in the international archaeological journal *Antiquity*. The first author of the paper is Associate Research Fellow Wang Xueye from the Center for Archaeological Sciences. The corresponding authors are Associate Research Fellow Tang Zihua from the Institute of Geology and Geophysics, Chinese Academy of Sciences, and Associate Professor Li Yuqi from the School of History, Nankai University. Co-authors include Research Curator Lu Lipeng from the Xinjiang Institute of Cultural Relics and Archaeology, Research Curator Wang Bo from the Xinjiang Museum, Professors Zhang Guiying and Lü Hongliang from the Center for Archaeological Sciences, Sichuan University, Wang Wenjun from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, and Researcher Patrick Roberts from the Max Planck Institute of Geoanthropology, Germany.
Recent archaeological research indicates that long before the official opening of the Silk Road in the 2nd century BCE, Inner Asia was already a crucial corridor for the spread of various domesticated plants and animals, artifacts, technologies, and ideas across Eurasia. However, the vast deserts and high mountains of the region posed natural barriers to interaction. This has led scholars to ask: How did early populations in Inner Asia overcome geographical obstacles to establish extensive connections?
To answer this question, current scholarship has particularly focused on two interaction mechanisms: the long-distance migration of steppe pastoralists, and the networked interactions formed by mountain pastoralists along the Inner Asian Mountain Corridor due to seasonal vertical transhumance. These two mechanisms have, to a considerable extent, successfully explained the modes of interaction among early nomadic populations in Inner Asia. However, they struggle to elucidate the interaction processes among oasis populations, which later became the backbone of the Silk Road.
This study selects the Zaghunluq Cemetery (Figure 1), located on the edge of the Qiemo Oasis in eastern Inner Asia, a typical Silk Road oasis in Xinjiang, as a case study to delve into the interaction mechanisms of early oasis populations. Over a hundred tombs have been excavated at this cemetery, dating from the 6th century BCE to the 1st century CE, and are distributed on an ancient oasis that has now turned into desert. The typical oasis environment, well-preserved human bones and grave goods (Figure 2), provide ideal materials for studying the mobility and interaction networks of oasis populations.
This study, through stable strontium, oxygen, carbon, and nitrogen isotope analysis of 33 individuals from Zaghunluq Cemeteries I and II, reconstructed the migration patterns of ancient oasis populations in this region, as well as their closely related dietary structures.
Figure 1 Location of the Zaghunluq Cemetery and a schematic map of ancient Silk Road routes.
Figure 2 (a) Tomb 96QZIIM2; (b) Tomb 96QZIM24 (Photos taken at the Zaghunluq Cemetery exhibition room).
Multiple lines of evidence, including carbon and nitrogen isotopes, archaeozoological and archaeobotanical remains, and grave goods, indicate that the Zaghunluq inhabitants primarily engaged in sedentary agriculture (mainly C3 plants), supplemented by diverse subsistence activities such as herding, hunting, and fishing. Strontium and oxygen isotope analysis further reveals that 76% of the individuals (25) primarily confined their activities to within 10 km of the cemetery; only 12% (4 individuals) likely lived within a 20-50 km radius or engaged in seasonal vertical transhumance between the oasis and mountains; and another 12% (4 individuals) exhibited clear long-distance migration characteristics. Combined with the strontium-oxygen isotope spatial distribution patterns constructed in this study (Figure 3), it is possible to clearly identify that one adult female (M65J) most likely originated from the Lop Nur region, approximately 300 km away. Her bone nitrogen isotope characteristics are also consistent with those of local populations found in archaeological discoveries. The isotope values of another adult male (M24C) are consistent with those from the Eastern Tianshan Mountains and western Central Asia, also indicating he had undergone long-distance migration (Figure 4).
Figure 3 (a) Distribution map of measured and machine learning-predicted strontium isotope data in the Tarim Basin and surrounding areas; (b) Spatial distribution map of measured strontium isotope data from plants around the Zaghunluq Cemetery.
Figure 4 Geographic origin simulation for 4 non-local individuals from the Zaghunluq Cemetery (darker colors indicate a higher probability of origin from that area).
The analysis results indicate that the lifestyle of the Zaghunluq population was based on sedentary agriculture, but their daily activity range was broader than that of typical sedentary agriculturalists, emphasizing the utilization of resources from the oasis and surrounding desert and mountain areas. This subsistence strategy facilitated the establishment of "strong ties" through frequent interactions, i.e., stable and close connections with neighboring oasis populations and mountain pastoralists. Meanwhile, individuals who had clearly undertaken long-distance migrations (such as M65J and M24C) likely established "weak ties" over a wider area—connections that, in complex networks, appear sparse but are critically important. This network structure, characterized by the coexistence of strong and weak ties, meets the conditions for the emergence of the "small-world effect" in complex network theory. It could effectively promote the long-distance transmission of materials and culture through a few trans-regional individuals, even on a foundation of overall sedentism. This phenomenon is also reflected in the associated grave goods. In the Group B tombs, where the two individuals involved in long-distance migration were buried, the variety of grave goods is richer, including foreign cultural elements such as silk, lacquerware, konghou harps, and ornaments with steppe animal styles (Figure 5). This may be a direct reflection of weak ties promoting cross-regional cultural exchange.
Figure 5 (a) Lacquerware wooden cylinder (M24:12); (b) Double-handled jar; (c) Single-handled jar; (d) Konghou (harp) (M14:20); (e) Wooden comb with animal motifs (M14:33); (f) Pullover dress (M55:17).
This study, through multi-isotope analysis, reveals how typical oasis populations in Central Asia, within a complex geographical environment, actively participated in the construction and operation of regional interaction networks through local "strong ties" and "weak ties" established by a few individuals. This conclusion complements the two mechanisms previously focused on by scholars—the long-distance migration of steppe pastoralists and interactions along the Inner Asian Mountain Corridor. It greatly enriches our understanding of the modes of interaction among early populations in Inner Asia and provides new evidence for understanding the foundational basis and maintenance mechanisms of the Silk Road.
This research was supported by the National Natural Science Foundation of China (Grants No. 42072210, 42402192), the Independent Research Project of the Institute of Geology and Geophysics, Chinese Academy of Sciences (No. IGGCAS-201905), and the Fundamental Research Funds for the Central Universities (Grants No. YJ202366, 63243010), among others.