Dikika baby dating
To do that, the team examined the bones both chemically and under a microscope.The chemical tests confirmed that the damage had occurred before the bones were fossilized; the microscopic examination confirmed that it was the result of cutting. Some of the cuts are V-shaped in cross section, for instance — a shape characteristic of those made by sharp tools — with scratches inside the cuts left by the tool's rough edge.
But their efforts still required planning because the nearest source of suitable rocks was about 6 kilometres away from where the bones were found. "We were hoping there would be older stuff [than my own findings]," Renne says.Further evaluation, however, would have to wait until the fossil was cleaned—a painstaking process in which the cementlike matrix is removed from the bone almost grain by grain with dental tools.It took Alemseged five years to expose key elements of the child's anatomy; he continues to analyze bones revealed since then.The pattern of magnetic field reversals — which occur at intervals in Earth's history — in the intervening sediments, and estimates of sedimentation rates, further refined the estimate."The best estimate is 3.39 million years," Mc Pherron says. "I think they have a really good case for 3.2 to 3.4 million years ago," he says.In particular, radioisotope studies had dated two important strata, one at the highest levels in the gully and the other near the bottom.
On the basis of these, the scientists knew that the bones could be no more than 3.42 million and no less than 3.24 million years old.
However, they probably weren't hunting, Mc Pherron says; it is more likely that they were scavenging predator kills.
Still, the search for large-animal meat is an important step in human development.
Within that range, he adds, the precise date isn't critical.
"The fact that they're older than 3 million is pretty exciting." However, the discovery doesn't mean that early hominins made tools.
The arid badlands of ethiopia's remote afar region have long been a favorite hunting ground for paleoanthropologists.