Magnetostratigraphy and Dating

Magnetostratigraphical Dating of the Earliest Occupation in Northeast Asia at the Xiaochangliang site in the Nihewan Basin in North China

         Timing of the earliest habitation and oldest stone technologies in different regions of the world remains a contentious topic in the study of human evolution. We contribute to this debate here with detailed magnetostratigraphic results on two exposed parallel sections of lacustrine sediments in the Nihewan Basin, North China, which for the first time place stringent controls on the age of Palaeolithic stone artifacts initially reported some two decades ago. Our palaeomagnetic findings indicate that the artifact layer resides in a reverse polarity magnetozone bounded by the Olduvai and Jaramillo subchrons. Coupled with estimated sedimentation rate, these findings constrain the layer's age to ~1.36 million years before present. This result represents the age of the oldest known East Asian stone assemblage consisting of unambiguous tool forms and the earliest definite occupation in this region as far north as 40^oN.

The extinction of diverse fossil assemblages (vertebrate, invertebrate and plant fossils) of the Jehol biota preserved in the lacustrine deposits, mainly in western Liaoning Province, northeastern China provides incredible opportunities to evaluate the environmental impacts on these past organisms. Excavation site at SHT section, showing lacustrine deposits with intercalated tuffs (yellow layers)