Earliest Presence of Humans in Northeast Asia
Summary of article appearing in Nature, Volume 413, 27 September 2001, page 413-417.
paleomagnetic dates show that stone artifacts from northern China date
to 1.36 million years ago. The tools from the site dated here, Xiaochangliang,
in the Nihewan Basin, were found over two decades ago, but were not
dated precisely. The artifacts are the oldest examples of recognizable
tool classes in
It is more difficult to date Asian sites than African sites because Asian sites typically lack volcanic materials that can be dated isotopically. The fossil mammals at the site lived for long periods of time and cannot be used to pin down the site’s exact age. This study examined two sections in the Nihewan Basin for paleomagnetic signals.
Paleomagnetic studies are based on shifts in the polarity of Earth’s magnetic field between periods of normal polarity, when magnetic north points to the north, and periods of reverse polarity, when magnetic north is to the south. The timing of the shifts and the approximate duration of the periods of normal and reverse are precisely known from other sites. The sediments collected at Xiaochangliang were measured to determine their magnetic polarity. The series of polarity shifts in the layers was then compared with the known paleomagnetic record to determine which paleomagnetic time periods were represented. Knowing that artifacts occur in a reverse period, the authors used the average sedimentation rate to calculate the age of the artifact layer to be 1.36 million years old.
tools and the dates associated with them are important because they
provide evidence for the timing of occupation of eastern Asia and for
the colonization of a relatively high-latitude (40º N) part of the region.
These dates imply that by 1.36 million years ago, humans had the ability
to travel long distances to reach Asia and that they did so with a relatively
simple set of tools. These dates also show that by 1.36 Ma, early humans
were able to adapt to the climate of northern