Fire, water to help unravel archaeological objects’ age

May 26th, 2009 - 3:36 pm ICT by IANS  

London, May 26 (IANS) Scientists are relying on fire and water to date archaeological objects by unlocking their “internal clocks”, with this simple yet novel method promising to be as significant for dating ceramic materials as radiocarbon has become for organic materials such as bone or wood.
Researchers from the Universities of Manchester and Edinburgh, behind the new technique, called it “rehydroxylation dating” to be used on fired clay ceramics like bricks, tile and pottery.

Working with The Museum of London, they have been able to date brick samples from Roman, medieval and modern periods with remarkable accuracy, up to 2,000 years back in time. But it has the potential to be used to date objects around 10,000 years old.

The method relies on the fact that fired clay ceramic material will start to chemically react with atmospheric moisture as soon as it is removed from the kiln after firing. This continues over its lifetime causing it to increase in weight - the older the material, the greater the weight gain.

In 2003, the Manchester and Edinburgh team discovered a new law that precisely defines how the rate of reaction between ceramic and water varies over time.

The technique involves measuring the mass of a sample of ceramic and then heating it to around 500 degrees Celsius in a furnace, which removes the water. The sample is then monitored in a super-accurate measuring device known as a microbalance, to determine the precise rate at which the ceramic will combine with water over time.

Using the time law, it is possible to extrapolate the information collected to calculate the time it will take to regain the mass lost on heating - revealing the sample’s age, said a Manchester and Edinburgh release.

Study co-author Moira Wilson, senior lecturer at the School of Mechanical, Aerospace and Civil Engineering (MACE), said: ” We are extremely excited by the potential of this new technique, which could become an established way of determining the age of ceramic artefacts of archaeological interest.”

These findings have been published online by the Proceedings of the Royal Society.

Related Stories

Tags: , , , , , , , , , , , , , , , , , , ,

Posted in Sci-Tech |