Ku With National Science Foundation support, Dr. Teh-Lung Ku and his colleagues will conduct uranium series dating on a series of speleothem (cave limestone) deposits from the archaeological/paleontological site of Zhoukoudian which is located near Beijing, China. This site is one of the most important in the world because its deposits span a major portion of the last Ice Age and contain both archaeological materials and hominid remains. The hominid cranial material from the site played a basic role in the definition of Homo erectus in Asia. Nine of the 13 layers at Zhoukoudian, locality 1 contain hominid remains. The layers are also very rich in archaeological materials including both stone tools and faunal remains and may contain the earliest evidence for the controlled use of fire. A major problem with the site has been the inability of scientists to obtain good age estimates for each layer. Dr. Ku and his colleagues will collect speleothem from secure geological contexts and conduct uranium series dating. Additionally, the age determination will be carried out using thermal ionization mass spectrometry - a recently developed technique that has revolutionized the geochronology because of the technique's unparalleled precision and sensitivity. It has the potential to extend the U-series dating limit from ca 350 ka to ca. 600 ka. Paleoanthropologists wish to understand how hominids developed both culturally and physically over time. Data to date indicate that the Far East played an important role in this process but unfortunately relatively few sites have been discovered and excavated in this part of the world. For this reason Zhoukoudian with its rich fossil and archaeological record is extremely important. More precise dating will allow these remains to be interpreted in a broader geographical context.