Radiometrically dating adjacent rocks
The most widely known form of radiometric dating is carbon-14 dating.
To determine the relative age of different rocks, geologists start with the assumption that unless something has happened, in a sequence of sedimentary rock layers, the newer rock layers will be on top of older ones. This rule is common sense, but it serves as a powerful reference point.You can learn more about fossils, dinosaurs, radiometric dating and related topics by reading through the links on the next page.Radiometric dating isn't the only method of determining the age of rocks.In addition, the oldest known moon rocks are 4.5 billion years old.
Since the moon and the Earth probably formed at the same time, this supports the current idea of the Earth's age.
With absolute age dating, you get a real age in actual years.