Appendix Radioactive Dating The technique of comparing the abundance ratio of a radioactive isotope to a reference isotope to determine the age of a material is called radioactive dating. Many isotopes have been studied, probing a wide range of time scales. The isotope 14C, a radioactive form of carbon, is produced in the upper atmosphere by neutrons striking 14N nuclei. The isotope, 14C, is transported as 14CO2, absorbed by plants, and eaten by animals.
The isotope 14C is radioactive, and beta-decays with a half-life of 5, years. The best estimate from this dating technique says the man lived between and BC. A potassium-argon method of dating, developed inmeasures the amount of 40Ar arising from the 40K decay and is compared to the amount of 40K remaining in the rock.
The age of our galaxy and earth also can be estimated using radioactive dating.
Nothing good can last-and in the case of carbon, a radioactive isotope found in Earth's atmosphere, that's great news for archaeologists. Many such fossils have been found in eastern Africa's Rift Valley, Granger was using radioactive isotopes in sediment to determine the age of rivers and caves. Dating fossils by examining the minute quantities of radioactive.