Relative dating, archaeological

Radioisotopes may occur in the earth naturally as primordial radioisotopes, formed when the planet was created, or be produced by natural or artificial processes. Most fast decaying primordial radioisotopes have long disappeared from the planet since the earth originated about 4.5 billion years ago, such isotopes have decayed and reached a final, stable form. The relatively few primordial radioisotopes still extant in the earth today, therefore, decay very slowly. Among these are potassium-40 and some isotopes of uranium, such as uranium-235 and uranium-238, which are of use for dating archaeologically related minerals and rocks (see Textboxes 15 and 16). 

FUN dating is applied to obtain a relative dating of bones found in the same archaeological site or deposit rather than for absolute dating. 

In 1853 and 1855 Wocel, an Austrian, published two papers on the analysis of specimens of ancient bronze which he had made, but in addition, summarized a number of earlier analyses He took an important step forward when he argued that the relative dating, or sedation, of ancient metal specimens mi t be reflected in their chemical compositions. A number of additional examples of early archaeological chemistry are given in the excellent books and reviews of Earle R. Caley 3. n, i2)... 

Physical and chemical dating methods which provide archaeology with absolute and relative chronologies. 

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