The fossil record suggests that at least two major human dispersals occurred across the Eurasian steppe during the Late Pleistocene, 10,000 years earlier than archaeologists previously believed.

Stone tools discovered in Mongolia by an international team of archaeologists indicate that modern humans traveled through the Eurasian steppe about 45,000 years ago.

According to a new study by the University of California at Davis, this is about 10,000 years earlier than archaeologists previously believed.

The site also points to a new location where modern humans may have first encountered their mysterious cousins, now extinct Denisovans, said Nicolas Zwyns, associate professor of anthropology and lead author of the study.

Zwyns conducted excavations from 2011 to 2016 at the Tolbor-16 site along the Tolbor River in the mountains of northern Hangai, between Siberia and northern Mongolia.

The excavations produced thousands of stone artifacts, with 826 stone artifacts associated with the oldest human occupation on the site. With long, regular blades, the tools resemble those found elsewhere in Siberia and northwestern China, indicating a large-scale dispersion of humans throughout the region, revealed Zwyns.

“These objects existed before, in Siberia, but not to such a degree of standardization,” Zwyns revealed .

“The most intriguing (aspect) is that they are produced in a complicated yet systematic way — and that seems to be the signature of a human group that shares a common technical and cultural background.”

And it was precisely this kind of techology– Initial Upper Palaeolithic–that helped scientists rule out the presence of Neanderthals of Denisovans at the site.

“Although we found no human remains at the site, the dates we obtained match the age of the earliest Homo sapiens found in Siberia,” Zwyns said. “After carefully considering other options, we suggest that this change in technology illustrates movements of Homo sapiens in the region.”

The age of the site, determined by luminescence dating on the sediment and radiocarbon dating of the bones of animals found near the tools, reveals an age of approximately 10,000 years before the fossil of a human skull from Mongolia, and approximately 15,000 years after that modern humans left Africa.

Evidence of soil development (grass and other organic matter) associated with stone tools suggests that the weather over a period became warmer and wetter, making the normally cold and dry region more hospitable for grazing animals and humans.

The preliminary analysis identifies bone fragments at the site as large bovine (wild or bison cattle) and medium (bovine, wild goats) and horses, who frequented the open steppe, forests and tundra during the Pleistocene, another sign of human occupation in the area.

Furthermore, the age of the stone tools also coincides with the estimates of age obtained from the genetic data for the first encounter between Homo sapiens and the Denisovans.

“Although we don’t know yet where the meeting happened, it seems that the Denisovans passed along genes that will later help Homo sapiens settling down in high altitude and to survive hypoxia on the Tibetan Plateau,” Zwyns explained.

“From this point of view, the site of Tolbor-16 is an important archaeological link connecting Siberia with Northwest China on a route where Homo sapiens had multiple possibilities to meet local populations such as the Denisovans.”

Earliest modern human in Mongolia

In early 2019, researchers reported the confirmation of a much-debated ancient human skull. The researchers revealed that after being dated and genetically analyzed, the specimen proved to be the earliest modern human yet discovered in the region.

The study detailing the findings were published in the journal Nature Communications.

Scientists used both radiocarbon dating as well as DNA analysis to reveal that the hominin fossil discovered in Mongolia–initially referred to as Mongolanthoropus– is in fact a modern human that inhabited the region some 35,000 years ago.

The fossil was dug up by archeologists in the Salkhit Valley northeast Mongolia.

Previous studies have linked the skull cap to an uncharacterized hominin species, indicating that the specimen dates back from the Early Middle Pleistocene to the terminal Late Pleistocene.