Center for Archaeological Science, Sichuan University publishes new evidence of continuous occupation of Paleolithic cave sites in Southwest China.

Since Marine Isotope Stage 3 (MIS3), global climate, population dynamics, and human behavior patterns have undergone significant changes in many parts of the world. With the increase of archaeological evidence, our understanding of human species and technological trajectories in the Late Paleolithic of East Asia has become increasingly complex, and many key issues remain unclear in Southwest China. Recently, the Center for Archaeological Science, Sichuan University published a research paper titled "New Evidence of Human Occupation in Southwest China Since 44,800 Years ago" in the international journal Lithic Technology, which deeply discussed the lithic technology of the Zhaoguodong site in Guizhou, proposing that the lithic technology of the site has maintained considerable stability in the past 45,000 years. This discovery means that modern humans in southern China may have developed a unique pattern of environmental and behavioral adaptation.

The Zhaoguodong site is located in Yankong Village, Gaofeng Town, Gui'an New District, Guizhou Province. It was jointly discovered by the Guizhou Provincial Institute of Cultural Relics and Archaeology, the Department of Archaeology of Sichuan University, and the Chengdu Institute of Cultural Relics and Archaeology in 2016. It has undergone five consecutive years of archaeological excavation and was selected as one of the Top Ten Archaeological Discoveries in China in 2020. The site has accumulated 25 radiocarbon dating data, which, after calibration, show that the bottom layer of the site dates back to 44,881-43,086 cal.BP, and the top layer dates back to 7,934-7,752 cal.BP. According to the dating results, this study divides the site into 2 phases and 5 stages. The first phase is the Late Pleistocene (the first stage is layers 25-21, the second stage is layers 20-17, and the third stage is layers 16-9), and the second phase is the Holocene (the first stage is layers 8-2, and the second stage is layer 1). A considerable number of stone artifacts have been unearthed in each phase, providing a rare window to examine the diachronic changes in lithic technology.

The study shows that black flint is the most common raw material in the site. There were some changes in the later period, but flint was the main material overall. The research team discovered rich and stable black flint outcrops in the field survey. The cores in the first stage of the first phase did not use prepared platform technology, and were mainly unidirectional percussion, with shorter flaking sequences, mainly producing wide and long flakes. The number of dorsal scars on the flakes was 2-6, showing the same unprepared platform characteristics as the cores. Scrapers were mainly single-sided retouch. Three hearths and some burnt bones were also found in this stage. The cores in the second stage of the first phase adopted unidirectional and bidirectional flaking strategies, and seven hearths were found. Bipolar flaking technology and multidirectional flaking appeared in the third stage of the first phase, and some new sedimentary rock and metamorphic rock products appeared. A large number of charcoal particles and white ash strips appeared in the fire remains of this period, which may belong to major fire events and multiple fires in a short period of time, indicating that the frequency of visits by ancient humans to the site increased significantly. During the Holocene stage, the lithic technology of the Zhaoguodong site did not change much, mainly manifested in the appearance and use of pottery and ground stone tools, as well as the extensive use of bone tools. The hearth forms in this period were more fixed and overlapped each other.

This study reveals that the lithic industry of Zhaoguodong maintained considerable consistency from the Late Pleistocene to the Early Holocene, which not only provides evidence for the "Southern Route" theory of modern human migration, but also shows the population continuity in Southwest China after MIS3. The site was first discovered and excavated nearly ten years ago. The archaeological remains are rich in content, and related results have been published in domestic and foreign academic journals such as Archaeology, American Journal of Physical Anthropology, and Journal of Archaeological Science: Reports, and were selected as one of the Top Ten Archaeological Discoveries in China, which has attracted widespread attention at home and abroad and has become one of the typical Late Paleolithic sites in Southwest China. Currently, more detailed studies on the site's zooarchaeology, paleoenvironment, vegetation, sedimentary micromorphology, OSL high-resolution chronological framework, and ancient DNA are underway. It is hoped that future research will reveal unresolved questions, such as the exact human species and continuity, the impact of climate fluctuations, and adaptation models that change over time.

Professor Lv Hongliang and doctoral student Zhang Xinglong from the Center for Archaeological Science, Sichuan University are the co-first authors of this article, and Associate Research Fellow Hu Yue from the Center for Archaeological Science is the corresponding author of this article. Co-authors also include Qin Yaping, Xu Pengcheng, master's graduates from the School of Archaeology and Museology of Sichuan University, Yang Guobing and Chen Yun, doctoral students, as well as Huang Ming and Jiang Ming, associate researchers from the Chengdu Institute of Cultural Relics and Archaeology, and Ben Marwick, professor of the Department of Anthropology at the University of Washington.

Figure: Geographical location of the Zhaoguodong site

Figure: Excavation plan of the Zhaoguodong site