A new analysis of Chusang, an archeological site on the high-altitude Tibetan Plateau, suggests that permanent residents may have set up camp thousands of years sooner than previously thought.

Previous analyses estimated that Chusang’s founding residents arrived about 5,200 years ago, but now a more comprehensive analysis by University of Innsbruck researcher Michael Meyer and co-authors suggests that it was inhabited — likely on a permanent basis — between 13,000 and 7,400 years ago.

“Upon leaving Africa, humans effectively spread out across most of the Earth, but the timing of their arrival in the highest Himalyan ranges has been unclear,” Dr. Meyer and his colleagues said.

“Among some of the best preserved sites for scientists to study is the Chusang site, which is located on the central plateau 50 miles (80 km) northwest of Lhasa at an elevation of 14,000 feet (4,270 m), near Chusang, a village known for its hydrothermal springs and extensive travertine formations.”

“Discovered in 1998, the site features 19 human hand- and footprints along the surface of a fossil travertine.”

In attempts to better date the settlement, the researchers used three different techniques, including thorium/uranium dating of samples taken from and adjacent to the prints; optically stimulated luminescence to determine the date of quartz crystals in the travertine; and radiocarbon dating on microscopic plant remains at Chusang.

Their new estimated range for the settlement is between 7,400 and 12,670 years ago.

“We report a reanalysis of the chronology of the Chusang site. The minimum age of the site is fixed at 7.4 thousand years (thorium-230/uranium dating), with a maximum age between 8.20 and 12.67 thousand calibrated carbon-14 years before present (carbon-14 assays),” the authors said.

The finding is consistent with research on the genetics of modern Tibetan Plateau people showing that they adapted genetically to the high-elevation environment beginning at least 8,000 years ago.

While some scientists have suggested that a human presence on the Tibetan Plateau at those early dates was only a result of short-term, seasonal movement from low-elevation base camps, this work shows that it is much more likely that the hand- and footprints were made by permanent residents.

“The distance between lowland environments and the Chusang site would have required at least 230 miles (370 km) of foot travel across the Himalayan arc — a path far too long and treacherous for temporary use of the site, and far greater than what has been documented among most historic hunter-gatherers,” said co-author Dr. Randy Haas, from the University of Wyoming.

“The early Tibetan Plateau settlers managed to survive at high elevation at least 7,400 years ago, before the development of an agricultural economy between 5,200-3,600 years ago.”

Details of the research were published in the Jan. 6, 2017 issue of the journal Science.

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M.C. Meyer et al. 2017. Permanent human occupation of the central Tibetan Plateau in the early Holocene. Science 355 (6320): 64-67; doi: 10.1126/science.aag0357