Thursday, February 11, 2010

Queen's Helps Produce Archaeological 'Time Machine'

An appropriately misleading title right from the press release.  This has nothing to do at all with the Queen f England (she's the only Queen who comes to mind when I see the word) which, when I first read it, thought she mighgt have given a DNA swab or something like in order to better match the bones of ancestors and such!  LOL!

Nah, no such thing.  But this is interesting news.  There is now or soon will be a new scale of calibrating carbon-14 dating that goes back to 50,000 years.  This isn't the place to get into a discussion about all the problems associated with carbon-14 dating (actually, the problems associated with most dating methodologies).  Here is the article about the new carbon dating "calibration curve."  Oh please - why couldn't they call it something in plain English that everyone will understand? 

I read the article and I'm not reassured that despite the improvements it is now an accurate dating mechanism.  But I'm hoping this new one is more accurate than what's been used for the past - just how long has carbon-14 dating been around???

Press release from Queen's University Belfast
Queen's helps produce archaeological 'time machine'
Researchers at Queen's University have helped produce a new archaeological tool which could answer key questions in human evolution.

The new calibration curve, which extends back 50,000 years is a major landmark in radiocarbon dating-- the method used by archaeologists and geoscientists to establish the age of carbon-based materials.

It could help research issues including the effect of climate change on human adaption and migrations.

The project was led by Queen's University Belfast through a National Environment Research Centre (NERC) funded research grant to Dr Paula Reimer and Professor Gerry McCormac from the Centre for Climate, the Environment and Chronology (14CHRONO) at Queen's and statisticians at the University of Sheffield.

Ron Reimer and Professor Emeritus Mike Baillie from Queen's School of Geography, Archaeology and Palaeoecology also contributed to the work.

The curve called INTCAL09, as just been published in the journal Radiocarbon. It not only extends radiocarbon calibration but also considerably improves earlier parts of the curve.

Dr Reimer said: "The new radiocarbon calibration curve will be used worldwide by archaeologists and earth scientists to convert radiocarbon ages into a meaningful time scale comparable to historical dates or other estimates of calendar age.

"It is significant because this agreed calibration curve now extends over the entire normal range of radiocarbon dating, up to 50,000 years before today. Comparisons of the new curve to ice-core or other climate archives will provide information about changes in solar activity and ocean circulation."

It has taken nearly 30 years for researchers to produce a calibration curve this far back in time.

Since the early 1980s, an international working group called INTCAL has been working on the project.

The principle of radiocarbon dating is that plants and animals absorb trace amounts of radioactive carbon-14 from carbon dioxide in the atmosphere while they are alive but stop doing so when they die. The carbon-14 decays from archaeological and geological samples so the amount left in the sample gives an indication of how old the sample is.

As the amount of carbon -14 in the atmosphere is not constant, but varies with the strength of the earth's magnetic field, solar activity and ocean radiocarbon ages must be corrected with a calibration curve.

Most experts consider the technical limit of radiocarbon dating to be about 50,000 years, after which there is too little carbon-14 left to measure accurately with present day technology.

No comments:

Related Posts Plugin for WordPress, Blogger...