Introduction
Sanxingdui is a Bronze Age site located in western Guanghan County, 40km north-east of Chengdu city (Figure 1). It covers an area of approximately 12km2 and dates to c. 2700–1000 BC. Discovered in 1928, the first excavation at Sanxingdui was carried out in 1934 by the curator of the West China Union College Museum, David C. Graham. In 1986, two sacrificial pits (Pits 1 and 2) were found, containing over 900 bronze, gold, jade and ivory artefacts (Sichuan Provincial Institute of Cultural Relics and Archaeology 1999). Excavation at Sanxingdui has also provided important evidence for a multi-centred development of metallurgy, urbanism and culture in China during the second millennium BC (Ge & Linduff Reference Ge and Linduff1990).
Maps showing the location of Sanxingdui (top source: National Platform for Common Geospatial Information Services; bottom source: China Reference China2022).
Since 1986, continuous archaeological research has investigated important areas around Sanxingdui, including various parts of the urban site, the Yueliangwan and Cangbaobao walls, the Qingguanshan site and the Renshengcun cemetery, through which the distribution and structural layout of Sanxingdui has become clearer (Sichuan Provincial Institute of Cultural Relics and Archaeology 1998; Chen & Lei Reference Chen and Lei2004; Ran & Lei Reference Ran and Lei2020). In recent years, the collation of previous archaeological work has demonstrated that Sanxingdui was a centralised urban area and has produced evidence for the use of ritual performances involving public sacrifice of valuable objects as a method of community integration (Flad Reference Flad2018).
In April 2019, the Propaganda Department of Sichuan Province implemented the Ancient Shu Civilization Protection and Inheritance Project to focus on archaeological work at Sanxingdui. In March 2020, the Sichuan Provincial Institute of Cultural Relics and Archaeology, together with various universities and research institutes, re-launched excavation of the sacrificial area. This excavation is a major project of the State Administration of Cultural Heritage of China and employs sophisticated and advanced analytical techniques, through which increasingly detailed information has been revealed. So far, six new pits have been discovered and a large number of new artefacts have been recovered, compared with Pits 1 and 2.
The newly discovered pits
Pits 3–8 are located adjacent to Pits 1 and 2 and are all rectangular in shape, measuring between 3.5 and 20m2 (Figure 2). Four cabins were built over them to maintain consistent temperature and humidity for the excavation (Figure 3). In addition, an on-site laboratory was established to ensure that artefacts were protected immediately upon excavation. Excavation was spit based and carried out using 300 × 300mm and 0.5 × 0.5m grids, dependent on each pit's size, with each excavated spit measuring 50–100mm in depth. All excavated soil was collected and recorded. In addition, each spit was 3D scanned once completed and a 3D model was created using Agisoft Metashape Pro v1.5.0. Polymer bandages were used to extract fragile organic evidence, such as ivory, which was removed to the laboratory for further cleaning (Xiao et al. Reference Xiao2022) (Figure 3D).
Photographs of the excavation: A) excavation of Pit 3 (source: Xinhua News Agency 2021b); B) total station mapping and recording (source: Xinhua News Agency 2021b); C) hyper-spectral analysis (source: Sanxingdui Museum 2022); D) ivory artefact being excavated with the help of polymer bandages (source: Xiao et al. Reference Xiao2022: 110).
Excavated artefacts
The deposition of the artefacts within the newly discovered pits displays clear differences. Artefacts were buried in obvious layers in Pits 3, 4, 7 and 8, with mainly ivory in the upper layers and bronze artefacts in the lower layers. Pit 5 contained predominantly small gold objects and ivory products, while Pit 6 contained a ‘wooden chest’ featuring red paint produced with cinnabar (Figure 4A & B).
A) The ‘wooden chest’ from Pit 6 (source: Wu & Wu Reference Wu and Wu2021); B) close-up of cinnabar pigment (source: Ran et al. Reference Ran2022: 26); C–D) remains of plant-based textiles from Pit 4 (source: National Cultural Heritage Administration 2021).
Bronze objects
The excavated bronze objects are predominantly vessels and figurines. Many new object types have been discovered compared with sacrificial Pits 1 and 2, such as the kneeling figurine with a Zun (bronze ritual vessel) on its head from Pit 3 (Figure 5: left). The upper part is a wide, flared-mouth Zun with a unique dragon-shaped decoration on its shoulder, while its ring foot is truncated. The Zun stands on a square plate, below which is a kneeling figurine with its hands clasped in front; obvious welding marks can be seen between both elements. The body, arms and legs of the kneeling figurine were also cast separately and welded together (Xu et al. Reference Xu2021b). In Pit 4, a kneeling statue with twisted head was found cast as a whole. Its body featured swallow tail patterns, which are commonly found on contemporaneous bronze wares in the middle and downstream areas of the Yangzi River (Xu et al. Reference Xu2021a) (Figure 5: right).
Bronze objects: left) kneeling bronze figure with Zun from Pit 3 (source: Xu et al. Reference Xu2021b: back cover); right) bronze figure with swallow tail pattern from Pit 4 (source: Xu et al. Reference Xu2021a: 107).
Gold objects
These mainly include gold foil ornaments in shapes including stripes, circles and birds. A golden mask, weighing around 280g, was excavated from Pit 5 (Figure 6). It was produced using gold-silver alloys, with a gold content of about 85 per cent. To date, this mask is believed to be the largest and heaviest dated to the Shang and Zhou Dynasties (seventeenth to third centuries BC) (Li et al. Reference Li2022).
The golden mask from Pit 5 (source: Li et al. Reference Li2022: 109–10, 113 & back cover): A) location within the pit; B) prior to conservation; C) following conservation; D) illustration viewed from sides and below.
Organic remains
The advanced techniques used have also helped to discover increasing organic evidence. Phytolith analysis, for example, has shown that plant textile remains contained within an ash layer in Pit 4 predominantly comprise bamboo (Bambusoideae) (Figure 4C & D).
Dating Pit 4
Over 100 samples, mostly comprising carbon, have been collected for radiocarbon dating. Six dates, all from Pit 4, have been produced so far, which suggest that this feature dates to 1260–924 cal BC (Wu et al. Reference Wu, Ran and Lei2021).
Discussion
The application of advanced scientific methods throughout the excavation of the newly discovered pits allows the sacrificial custom of the Sanxingdui Culture to be understood in greater detail. The newly discovered artefacts provide a wealth of material evidence, allowing us to explore exchange between the Chengdu Plain and Central Plains, and the middle and downstream areas of the Yangzi River. The radiocarbon dates for Pit 4 complement the chronology for the sacrificial pits, which has been long debated. According to the artefacts and their pattern of burial, Pits 1–4, 7 and 8 roughly date to Yinxu Phase IV (c. 1200–1000 BC), while Pits 5 and 6 are probably early Western Zhou (c. 1046–950 BC) (Ran et al. Reference Ran2022).
Conclusion
The current excavations at Sanxingdui are unprecedented in terms of their methodology and popular interest. In June 2021, Sichuan University organised an international online symposium focusing on the new discoveries, and the invited scholars provided insightful discussion regarding multiple aspects of the site. As the excavations proceed, the systematic differences between the various pits, as well as their precise chronology, will become clearer, allowing us to provide an increasingly detailed understanding of the dynamics of the Sanxingdui Culture and how it compares with other contemporaneous Bronze Age urban centres in early China.
Funding statement
This research was funded by the China Postdoctoral Science Foundation (2019M653456), the National Social Science Fund of China (grant no. 15ZDB056) and Sichuan University (2021CXC14 & 2035xd-02).
