Homo erectus reached China 1.7 million years ago, 600,000 years earlier than thought

Somewhere in the layered sediments of Yunxian County, China, two ancient skulls sat buried for more than a million years. Discovered in 1989 and 1990, the fossils were recognized as belonging to Homo erectus, the direct ancestor of modern humans, but their precise age remained contested. Estimates put them at roughly 1.1 million years old. A new analysis published in Science Advances on February 18, 2026, revises that figure substantially: the Yunxian H. erectus fossils are 1.7 million years old, pushing the earliest known presence of our ancestors in eastern Asia back by approximately 600,000 years.

A dating method built for deep time

Conventional carbon-14 dating cannot reach this far into the past; its practical limit is around 50,000 years. The research team used a technique called aluminum-26 and beryllium-10 (Al-26/Be-10) burial dating, which can accurately date materials as old as 5 million years.

The method exploits cosmic ray physics. When high-energy cosmic rays strike quartz minerals near the Earth's surface, they produce two radioactive isotopes - aluminum-26 and beryllium-10. Once sediment is buried deeply underground and shielded from further cosmic radiation, isotope production stops and radioactive decay takes over. Because aluminum-26 and beryllium-10 decay at different, precisely known rates, the ratio of the two isotopes remaining in sediment samples from the same stratigraphic layer as a fossil reveals how long that sediment has been buried.

Lead author Hua Tu, from the Institute of Marine Sciences at Shantou University and the College of Geographical Sciences at Nanjing Normal University, described the approach: "By using aluminum's and beryllium's known decay rates, and comparing the ratio of the two types of atoms left in sediment samples surrounding a fossil, researchers can calculate how long a fossil has been buried."

Reshaping the dispersal timeline

The result - 1.7 million years of burial - places the Yunxian fossils in a period when H. erectus was also appearing in Georgia (Dmanisi, roughly 1.85 million years ago) and Java (roughly 1.5 to 1.8 million years ago). It positions eastern China as part of an early and rapid radiation of hominins out of Africa, not a later secondary wave as some models proposed.

Christopher J. Bae, corresponding author and professor in the Department of Anthropology at the University of Hawaii at Manoa, framed the significance: "While Homo erectus, our distant ancestor, is widely recognized to have originated in Africa before dispersing into Eurasia, the precise timeline of its arrival in eastern Asia was unknown. Using the combination of the Yunxian H. erectus fossils and burial dating data, we have now been able to recreate a fairly robust dating reconstruction of when these hominins appeared in eastern Asia."

Open questions remain

The revised date resolves one debate while opening others. Bae acknowledged that the chronology still leaves the broader picture incomplete: "These findings challenge long-held assumptions regarding when the earliest hominins are thought to have moved out of Africa and into Asia. While these results are significant, the mystery of exactly when H. erectus first appeared and last appeared in the region remains."

One question the study raises directly is whether H. erectus was even the first hominin to reach eastern Asia. If the species arrived 1.7 million years ago and the Yunxian fossils are among the earliest eastern Asian evidence, earlier occupants may yet be found, or the pattern may reflect sampling gaps in the fossil record rather than genuine absence. The authors are explicit about this uncertainty: "If H. erectus was not the earliest occupant to reach Asia, alternative species must be considered."

The isotope analysis is robust for the sediment layers sampled, but burial dating carries its own limitations. Post-depositional disturbance of sediments, which can mix materials of different ages, remains a concern in any burial dating study. The team applied their method to multiple sediment samples from the same stratigraphic context to reduce this risk, but independent verification from additional Yunxian samples would further strengthen the age estimate.

The research was funded by the National Natural Science Foundation of China and the U.S. National Science Foundation. Co-authors include researchers from Shanxi University, Purdue University, and Nanjing Normal University.