Absolute dating techniques
An early summary of them is found in Charles Lyell's .
It is not about the theory behind radiometric dating methods, it is about their , and it therefore assumes the reader has some familiarity with the technique already (refer to "Other Sources" for more information).
As an example of how they are used, radiometric dates from geologically simple, fossiliferous Cretaceous rocks in western North America are compared to the geological time scale.
However, to read any clock accurately we must know where the clock was set at the beginning.
Most people think that radioactive dating has proven the earth is billions of years old.