Ancient clay has internal clock (big news for historians and archaeologists)

BBC News Report

A new way of dating archaeological objects has been found, using water to unlock their "internal clocks".

Fired clay ceramics start to react chemically with atmospheric moisture as soon as they are removed from the kiln. Researchers believe they can pinpoint the precise age of materials like brick, tile and pottery by calculating how much its weight has changed.

Accurate only up to 2,000 years so far, but they're working on getting it up to 10,000.

The value of such a discovery to archaeologists and historians is almost priceless, because pottery fragments are just about the commonest thing to be found at archaeological digs. Other trade goods and household objects - textiles, furniture and other things not made out of metal or stone - perish with time, and metals were often found and melted down. Ceramics contain no carbon, so hitherto it's been impossible to date a sample accurately. Now we can.

Pottery is often our only clue to things like trade between ancient cultures, the usages of daily life, etc. Ancient records were often made on clay tablets. Now, for the first time, all this stuff can be dated accurately without external references.

The same goes for bricks. At last, the ruins of brick-built structures can be correctly dated.

I predict a revolution.

I think that is awesome. I think it is a little wierd that they just figured out how to do this kinda of test. I would think that they would have thought of weighting the pots/tables when they found them. Either way this is great. But I doubt they will test things that they have already found... Wouldnt want to tell the general population how old things really are.

The dreaded Doublepost Demon makes an apparition...

[edit on 29/5/09 by Astyanax]

reply to post by Topsy_Cret

Perhaps it's simply be a case of an accurate enough weighing device only now becoming available?

The sample is then weighed in a "super-accurate" device, known as a microbalance, to determine the precise rate at which the material will combine with water over time. Source

Online brochure and spec. sheet for Sartorius Microbalance

My guess is that this new method will prove of limited value. Too many unknown variables. The weight and degree of firing in the kiln. The environment in which the material was stored, unknown movement over the years, climactic changes, humidity, etc.

Mike

reply to post by mmiichael


It may have some value in determining comparative ages in the same sites. In these cases they do a series of blind tests against known ages and see how they do.