Dating cave sediments Sex web chatrandom

The original excavations, conducted from 2001 to 2004, dug into four regions of the cave, including a couple of sites along its eastern wall, where some fossils were found.Rather than damaging the fossils by dating them directly, the team looked to the sediments in which they were found.

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Dating on the gravelly sediment layer containing the fossils suggested it was deposited between 100,000 and 60,000 years ago; just above it is a layer of volcanic ash that was dated to about 60,000 years ago.

This suggests that the fossils themselves couldn’t possibly be younger than 60,000 years old, the team reports online today in .

The layers included a handful of volcanic tuff layers, sediments bearing additional artifacts linked to —and, beneath them all, a sediment layer that matched the one in which the original fossils were found.

The team then used numerous techniques to date the various sediments.

The team dated three arm bones found at different locations within the cave during previous excavations.

Using uranium-thorium dating—which is based on the radioactive decay of uranium and thorium isotopes in a material—they found dates ranging from about 66,000 to 87,000 years old.Instead of living 18,000 years ago, as they originally reported, the hobbit lived between 60,000 and 100,000 years ago—some 10,000 years before makes it “impossible to argue that it is a pathologically-dwarfed modern human,” says Russell Ciochon, a paleoanthropologist at the University of Iowa in Iowa City who was not involved in the study.“In my opinion, this paper drives the final nail in the coffin” of that hypothesis.Remains of early humans such as Neanderthals and Denisovans have been discovered at just a limited number of sites in Europe and Asia.This has long frustrated archaeologists, who are confident that many more locations were occupied throughout these regions.So far, they have focused on mitochondrial DNA, but hope to be able to find nuclear DNA as well, which would provide additional genetic information about the hominins.

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