Problems with radiometric and carbon 14 dating
The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.
Libby received the Nobel Prize in Chemistry for his work in 1960.
However, the methods must be used with care -- and one should be cautious about investing much confidence in the resulting age...
especially in absence of cross-checks by different methods, or if presented without sufficient information to judge the context in which it was obtained.
Since 1947, scientists have reckoned the ages of many old objects by measuring the amounts of radioactive carbon they contain.
New research shows, however, that some estimates based on carbon may have erred by thousands of years.
Absolute dating provides a numerical age or range in contrast with relative dating which places events in order without any measure of the age between events.
Particular isotopes are suitable for different applications due to the type of atoms present in the mineral or other material and its approximate age.Scientists at the Lamont-Doherty Geological Laboratory of Columbia University at Palisades, N.Y., reported today in the British journal Nature that some estimates of age based on carbon analyses were wrong by as much as 3,500 years.They arrived at this conclusion by comparing age estimates obtained using two different methods - analysis of radioactive carbon in a sample and determination of the ratio of uranium to thorium in the sample.In some cases, the latter ratio appears to be a much more accurate gauge of age than the customary method of carbon dating, the scientists said.