This site discusses the concept of radiometric dating. The discussion includes a brief history of atomic research, definitions of isotopes and the different types of radioactive decay including potassium-argon and carbon-14, half lives for some common isotopes and a examples of both minerals and organic matter that have been dated using radiometric techniques. This site is part of the online edition of the USGS published book “Geologic Time” William L. Newman . The site also provides information about how to obtain a print version of the book.
