How to alter carbon 14 dating
WHEN Willard Libby and his col leagues introduced carbon-14 dating a number of years ago the technique was immediately recognized as a potentially valuable tool for objectively determining the age of carbonaceous archeological specimens.
The basic validity of carbon-14 dating has now been established beyond reasonable doubt.
Recently, the technique of tree-ring dating (dendro chronology) as applied to bristlecone pines has figured prominently in discussions of the validity and limitations of carbon-14 dating.
This is because (1) tree-ring dating is considered to be an independent method of determining absolute dates— precise to the year; (2) tree-ring dates of up to 9,000 years have been reported; (3) tree-ring dates generally harmonize with carbon-14 dates.
Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 would remain undecayed).
This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old).Another characteristic of carbon 14 is that it is continually being formed in the upper atmosphere as a product of the reaction between neutrons produced by cosmic rays and nitrogen atoms.These carbon 14 atoms then instantaneously react with oxygen present in the atmosphere to form carbon dioxide.What has not been established securely are the limitations of the method.All competent scholars agree that occasionally carbon-14 dates are at variance with other scientific data.