With these major discoveries at Yuchanyan, new questions arose. What was the function of the early, “primitive” pottery? Were there more rice remains at the site that could be excavated from secure contexts? Was the rice wild or domesticated? What was the exact dating of all of the periods of occupation in the cave? How was the cave used? Because of the importance of the site and the many questions it gave rise to, further excavations and the application of new field and analytical techniques were needed. Under the guidance of the senior Chinese archaeologist Prof. Yan Wenming 严文明 of Peking University, an international collaborative team, with Prof. Ofer Bar-Yosef leading the American side and Prof. Yuan leading the Chinese side, was assembled.
The main objectives of the new excavations in 2004 and 2005 were to clarify the site formation processes of the Yuchanyan Cave deposits; to better understand the stratigraphy of the site; and to define and securely date the various phases of the occupational history of the site. In order to do this, the international team focused on micromorphological (Prof. Paul Goldberg, BU) and biomineralogical analyses (Prof. Steve Weiner, Weizmann Institute) accompanied by a major dating project based on the collection of numerous charcoal and bone samples (Profs. Wu Xiaohong 吴小红, Peking University, and Elisabetta Boaretto, Weizmann Institute). In addition, soil sampling for pollen, phytolith, and microfaunal studies (Gu Haibin 顾海滨, Hunan Institute of Archaeology and Cultural Relics), and flotation for plant remains was done (Prof. Zhang Wenxu 张文绪, China Agricultural University). The animal bones excavated in 2004-2005 were analyzed not only to identify the different species present, as is typically done in China, but also to understand how the animals were hunted and processed (taphonomic analyses) (Dr. Mary Prendergast, Harvard). A typological study of the stone tools recovered showed the same tool categories known from the first excavations, dominated by core-choppers and retouched flakes (Profs. Ofer Bar-Yosef and David Cohen, and Ms. Qu Tongli 曲彤丽 [Peking University graduate student]). A few additional pottery sherds were found during the 2004-2005 seasons, as well.
As a result of the collaborative fieldwork and the cutting edge analytical techniques applied to Yuchanyan cave, the project is now able to arrive at a much clearer understanding of the how humans used the cave. A series of over three dozen radiocarbon dates have been determined on samples carefully collected, prepared, and analyzed by Profs. Wu and Boaretto to securely date the occupational history of Yuchanyan Cave to between ca. 13,800-21,000 years ago (calibrated radiocarbon years). The early pottery in the cave is found in deposits dating 18,300 and 15,430 years ago (calibrated), making it among the earliest ceramic vessels in the world. The still preliminary results of the micromorphological and biomineralogical studies of the sediments in the cave can demonstrate that the 1+ meter thick deposits in the cave were primarily formed not by natural processes but rather, by human action, such as burning wood and bringing clay into the cave. Much of the research on Yuchanyan is still in progress, so the summary above can only briefly discuss the preliminary results. Papers and reports on the Yuchanyan excavations and analyses are forthcoming in 2008-09.
Yuchanyan Cave presents an excellent case by which to understand hunter-gatherer behavior in late Pleistocene South China. We now know that occupants of the cave, inhabited in the warming period at the end of the last Ice Age, were making special adaptations to the changing environment of the region. These included focused hunting strategies and the earliest, most securely dated known use of pottery. The purpose of the pottery still remains an open question, with more research to be carried out on the recovered pottery sherds.