Scientists have used the uranium series method to refine the dating of an ancient skull from the Petralona cave in Greece. They concluded that the remains belonged to Homo heidelbergensis, who lived at least 277,000 years ago. The results of the study were published in the Journal of Human Evolution.
The Petralona Cave is a Paleolithic site located in northern Greece, approximately 55 kilometers from Thessaloniki. In 1960, local residents discovered a well-preserved skull of an archaic man, which does not resemble the remains of either modern humans (Homo sapiens) or Neanderthals (H. neanderthalensis). The skull belonged to a man with a powerful brow ridge, a massive braincase, and a large facial skeleton. Among other ancient skulls, it most closely resembles the remains of the so-called Rhodesian man (H. rhodesiensis), found more than a hundred years ago in what is now Zambia.
The skull from the Petralona cave was not found by archaeologists, but by local residents. Because of this, the exact stratigraphic position of these remains on the monument remains unknown, although it is noted that it was found near the wall of the cave. Including for this reason, the age of the remains has remained a subject of debate among scientists. Using different methods, they obtained dates from approximately 700 to 150 thousand years. In particular, using the method of electron paramagnetic resonance, researchers estimated the age of the find at approximately 150-250 thousand years.
Christophe Falguères from the Institute of Paleoanthropology in Paris and his colleagues from the UK, Greece, China and France have refined the age of the find. This time they turned to the uranium series method, with which they dated the calcite deposits preserved directly on the skull, as well as samples of deposits from the Petralona cave.
The data obtained indicated that the skull was older than expected based on the electron paramagnetic resonance method. According to the scientists, the calcite deposit began to form on the remains of this man at least 286 ± 9 thousand years ago, that is, he may have lived around the same time as the aforementioned Rhodesian man, whose skull is about 299 ± 25 thousand years old.
At the same time, it is extremely difficult to determine how much earlier the remains were in the Petralona Cave before the calcite studied formed on them. Scientists have found that the dripstones on the wall of the cave, where the skull was supposedly originally located, probably appeared much earlier than this person lived. They are approximately 539 thousand years old. Thus, the results of the work done indicate that the archaic individual lived between 539 and 277 thousand years ago. The new dating is consistent with the conclusion that the skull belonged to Homo heidelbergensis in the broad sense of the understanding of this species (sensu lato).
The skull in the Petralona cave was found without the lower jaw. However, this did not stop researchers from recently reconstructing the appearance of the archaic man. Instead of the missing part, they used a model of the lower jaw of Homo heidelbergensis, who lived much earlier - about 609 ± 40 thousand years ago.
