Radiocarbon dating margin of error
The technique relies on the absorption of water into a freshly cut surface of the mineral, forming a rim of hydrated quartz.
The thickness of the rim reveals how long the surface has been exposed.
"For Australia and North America that might be OK, but for other places, or if there is no carbon present, we need other dating methods," Watchman said.
"[A margin of] 35% is excessive and we wouldn't accept that. For radiocarbon dating, which uses the ratio of different forms of carbon in an object, the error for a 5000 year old artefact was about 60 years, he said.
But he said carbon dating was limited in that it could only go back about 45,000 years.