Dating Nanjing Man

Recently discovered remains of Homo erectus at sites in China are providing an opportunity to assess the early migration of hominids out of Africa and their relation to the later populations of H. sapiens that emerged there about 500,000 years ago. A major difficulty, however, has been obtaining accurate dates for many of the fossils; this has hampered comparisons across sites and confounded the evolutionary history. The ages of the fossils are well beyond the dating range of radiocarbon, and most of the finds have been in caves lacking volcanic horizons (which can be K-Ar dated).