Radioactive decay and carbon dating
These new techniques can have a dramatic effect on chronologies.With the development of a new method of cleaning charcoal called ABOx-SC, Michael Bird helped to push back the date of arrival of the first humans in Australia by more than 10,000 years.Some of the first radiocarbon dates produced showed that the Scottish tombs were thousands of years older than those in Greece.The barbarians of the north were capable of designing complex structures similar to those in the classical world.In 2008 we could only calibrate radiocarbon dates until 26,000 years.Now the curve extends (tentatively) to 50,000 years.In addition, samples need to be thoroughly cleaned to remove carbon contamination from glues and soil before dating.
Australia has two machines dedicated to radiocarbon analysis, and they are out of reach for much of the developing world.
Other high profile projects include the dating of the Turin Shroud to the medieval period, the dating of the Dead Sea Scrolls to around the time of Christ, and the somewhat controversial dating of the spectacular rock art at Chauvet Cave to c.38,000 cal BP (c.32,000 BP) – thousands of years earlier than expected.
Radiocarbon dating has also been used to date the extinction of the woolly mammoth and contributed to the debate over whether modern humans and Neanderthals met.
Professor Willard Libby produced the first radiocarbon dates in 1949 and was later awarded the Nobel Prize for his efforts.
Radiocarbon dating works by comparing the three different isotopes of carbon.