Start What is radiometric dating and how is it used

What is radiometric dating and how is it used

Nearly 50 years after Darwin published , research on radioactive elements in rocks provided the first reliable evidence that the earth was old enough to accommodate the evolution of complex organisms.

Radiometric dating of granitic intrusions associated with the Caledonian orogeny yields ages between about 430 million and 380 million years.

The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be worked out.

There are two main methods determining a fossils age, relative dating and absolute dating.

By comparing the amount of each isotope in a sample, the age of the sample can be calculated.

Radiometric dating not only supports the geologic "evolution" of the Grand Canyon, it validates a central tenet in a much different theory of evolution - a theory introduced by Charles Robert Darwin in his 1859 publication, An important criticism of Darwin's theory of evolution was its requirement for "an almost infinite number of generations", when evidence at the time suggested earth was less than 100 million years old.

His estimate came into question after the discovery of naturally occurring radioactivity by the French physicist Henri Becquerel in 1896 and the subsequent recognition by his colleagues, Marie and Pierre Curie, that compounds of radium (which occur in uranium minerals)...

Another role of isotopic geochemistry that is of great importance in geology is radiometric age dating. Beginning with studies in the 1950s, a much better chronology and record of Pleistocene climatic events have evolved through analyses of deep-sea sediments, particularly from the oxygen isotope record of the shells of microorganisms that lived in the oceans.

For example, in 1991, two hikers discovered a mummified man, preserved for centuries in the ice on an alpine mountain.