The chronological question—when this person lived—was established through a combination of radiocarbon dating and the analysis of the cave’s stratigraphic context. Direct radiocarbon dating of the fragment placed it at greater than 50,000 years old—the upper limit of reliable radiocarbon dating, which uses the known decay rate of carbon-14 to determine how long ago an organism died. Beyond 50,000 years, the amount of carbon-14 remaining in a sample falls below the threshold of reliable measurement.
The layer from which the fragment came—layer 12 of the East Gallery—was associated with dating analyses placing the occupation at approximately 90,000 years ago. This figure, while carrying uncertainty given the complexity of cave stratigraphy and the limitations of available dating methods, is the best current estimate for when Denisova 11 lived. It is not a precise birthday. It is a range, centered on approximately 90,000 years before the present, that reflects the combined evidence of direct radiocarbon limits and stratigraphic dating of the surrounding sediment.
The dating establishes an important chronological context. Ninety thousand years ago is significantly before the period of modern human expansion out of Africa that most researchers place at roughly 60,000 to 70,000 years ago, though some models push earlier encounters. The people and hominins alive in the Altai Mountains 90,000 years ago were not encountering anatomically modern humans in the way that Neanderthals and Denisovans encountered them tens of thousands of years later. The meeting that produced Denisova 11 was an archaic-to-archaic encounter—two groups of human relatives, neither of whom was our immediate ancestor, coming together in the Siberian mountains.