Carbon dating technique

07-Oct-2019 16:25

Until this century, relative dating was the only technique for identifying the age of a truly ancient object.

By examining the object's relation to layers of deposits in the area, and by comparing the object to others found at the site, archaeologists can estimate when the object arrived at the site.

Carbon-14 is also passed onto the animals that eat those plants.

After death the amount of carbon-14 in the organic specimen decreases very regularly as the molecules decay.

Though still heavily used, relative dating is now augmented by several modern dating techniques.

University of Leicester archaeologists took four small samples from one of the ribs of the Greyfriars skeleton and sent them to two specialist units with the facilities to analyse them: the Scottish Universities Environmental Research Centre (SUERC) at the University of Glasgow, and the Oxford Radiocarbon Accelerator Unit, part of the University of Oxford’s Research Laboratory for Archaeology and the History of Art.

DR CHRISTINE PRIOR In conventional radiocarbon dating, you’re measuring the presence of the C-14 when you measure the radioactive decay.

The C-14 decays with the beta particle, and you have some detection equipment and you count the C-14s one by one.

The small pieces of bone were combusted to produce carbon dioxide which was then put through a mass spectrometer.

Testing two pieces each at two different facilities should provide consistent results – and indeed it did. The proportion of C-14 in the atmosphere, and hence in living things, is not constant but varies over the centuries, and it also varies between the atmosphere and the oceans.

University of Leicester archaeologists took four small samples from one of the ribs of the Greyfriars skeleton and sent them to two specialist units with the facilities to analyse them: the Scottish Universities Environmental Research Centre (SUERC) at the University of Glasgow, and the Oxford Radiocarbon Accelerator Unit, part of the University of Oxford’s Research Laboratory for Archaeology and the History of Art.

DR CHRISTINE PRIOR In conventional radiocarbon dating, you’re measuring the presence of the C-14 when you measure the radioactive decay.

The C-14 decays with the beta particle, and you have some detection equipment and you count the C-14s one by one.

The small pieces of bone were combusted to produce carbon dioxide which was then put through a mass spectrometer.

Testing two pieces each at two different facilities should provide consistent results – and indeed it did. The proportion of C-14 in the atmosphere, and hence in living things, is not constant but varies over the centuries, and it also varies between the atmosphere and the oceans.

Since the 1950s, geologists have used radioactive elements as natural "clocks" for determining numerical ages of certain types of rocks. "Forms" means the moment an igneous rock solidifies from magma, a sedimentary rock layer is deposited, or a rock heated by metamorphism cools off.