Carbon dating exposed

It finds the age of the sediment surrounding artefacts – sediment which may have once been outside sand trampled into caves tens of thousands of years ago – by measuring when it was last exposed to the sun.

carbon dating exposed-65

The reason behind this is it’s nearly impossible to separate crystalline grains that were once exposed to sunlight, which continually “resets” any trapped charge, from those that had already been locked away in rocks and accumulating electrons for millennia.“Multi-grain analysis of rock shelter sediments has a tendency to give older than expected dates because it can incorporate grains from the bedrock which haven't been fully bleached by the sun,” says Spooner.

Single-grain OSL needs specialised equipment and skilled personnel to analyse results, making it twice as expensive and more time-consuming than multi-grain analysis.

For archaeologists such as Spooner trying to date the first occupation of Australia, older age limitations of radiocarbon dating are frustrating, as it is exactly this period in which they are most interested.

So along with radiocarbon dating, they use a technique known as optically stimulated luminescence (OSL) dating.

Each sample type has specific problems associated with its use for dating purposes, including contamination and special environmental effects.

More information on the sources of error in carbon dating are presented at the bottom of this page.

How do you find out if it’s the remains of an ancient animal that stomped the land tens of thousands of years ago or a discarded scrap from a cooking fire only a few hundred years back?

An archaeologist’s staple is radiocarbon dating: judging the age of an organic sample from its carbon-14 – also known as radiocarbon – content.

The method was developed immediately following World War II by Willard F.

Libby and coworkers and has provided age determinations in archeology, geology, geophysics, and other branches of science.

Radiation counters are used to detect the electrons given off by decaying C-14 as it turns into nitrogen.

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