carbon 14 age dating - Numerical absolute geologic age dating
The goal of this lecture is come to come to a scientific understanding of geologic time and the age of the Earth.
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.
To get to that point, there is also a historical discussion and description of non-radiometric dating methods.
Prior to the late 17th century, geologic time was thought to be the same as historical time.
Archbishop James Ussher of Armagh, Ireland, 1654, added up generations from the Old Testament and determined that Earth formed on October 23, 4004 BCE.
Planetary scientists determine the chronology of features, such as whether a crater or streambed is younger.