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Radiocarbon dating by sheridan bowman

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Approaching archaeological techniques and artifacts from an interpretive viewpoint, the series looks in detail at specific classes of artifacts that have contributed most to our knowledge of the past, and at particular investigative techniques that are now being used to refine this knowledge and thereby to question previous assumptions.

In Radiocarbon Dating, Sheridan Bowman provides a much-needed introduction to the complex field of carbon dating.

Nevertheless, this prediction was sufficient for an American scientist called Willard Libby to perceive the basis of a dating method.

The theoretical aspects were formulated in the mid 1940s when Libby was Professor of Chemistry at the University of Chicago.

They showed that methane collected from the Baltimore sewage works had measurable radiocarbon activity, whereas methane manufactured from petroleum did not, and the implications of the findings for dating of carbonaceous materials were noted.

The most well-known of all the radiometric dating methods is radiocarbon dating.

In 1946 he published a paper suggesting that radiocarbon might exist in living matter.

One year later, a single-page paper appeared in the journal Science in which Ernest Anderson and Libby, together with collaborators in Pennsylvania, summarised the first detection of radiocarbon in material of biological origin.

And as far as we know, it has been forming in the earth’s upper atmosphere at least since the Fall, after the atmosphere was made back on Day Two of creation week (part of the expanse, or firmament, described in Genesis 1:6–8). Cosmic rays from outer space are continually bombarding the upper atmosphere of the earth, producing fast-moving neutrons (sub-atomic particles carrying no electric charge) (figure 1).1 These fast-moving neutrons collide with nitrogen-14 atoms, the most abundant element in the upper atmosphere, converting them into radiocarbon (carbon-14) atoms.

Since the atmosphere is composed of about 78 percent nitrogen,2 a lot of radiocarbon atoms are produced—in total about 16.5 lbs. These rapidly combine with oxygen atoms (the second most abundant element in the atmosphere, at 21 percent) to form carbon dioxide (CO This carbon dioxide, now radioactive with carbon-14, is otherwise chemically indistinguishable from the normal carbon dioxide in the atmosphere, which is slightly lighter because it contains normal carbon-12.