Charcoal carbon dating

Nearly a decade after Willard Libby’s initial work to develop this method, the half-life was revised from 5,568 to 5,730 years.

This meant that many calculated dates in papers published prior to this were incorrect.

charcoal carbon dating-47

We attribute this inconsistency to the post-depositional processes of phytoliths in soil, rather than to the uptake of old carbon from the soil.

Our results clearly show the potential for phytolith carbon dating at archaeological sites in the absence of other dating materials.

So what we do in Oxford is we use something called an ultrafilter.

We put the proteins into this filter – they’re in a liquid form – and then we zoom them around in a centrifuge, and the centrifuge and the filter together act to remove small molecular contaminants that come out of the collagen.

Professor of Archaeological Science and Deputy Director of the Oxford Radiocarbon Accelerator Unit Tom Higham explains the science behind radiocarbon dating and how he has refined this dating technique for archaeological research on ancient bones.

In this video, Tom says, “Radiocarbon has a half-life of 5,568 years”, yet in other places on the Science Learning Hub, we refer to radiocarbon as having a half-life of 5,730 years (this is known as the ' Cambridge half-life'). Basically, calculating radiocarbon ages requires the value of the half-life for carbon-14.

When you get down to 50,000 years ago, you’ve got 0.1% – that’s a tiny amount.

As a consequence of this, small amounts of contaminating carbon can really affect the reliability of the dates unless they’re removed.

Learn about developments in radiocarbon dating in our Athol Rafter heritage scientist timeline PROF TOM HIGHAM My expertise is in dating and archaeological dating using radiocarbon.

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