While the oldest known rocks on Earth are about 3.5 billion years old, researchers have found zircon crystals that are 4.3 billion years old [source: USGS].Based on the analysis of these samples, scientists estimate that the Earth itself is about 4.5 billion years old.Some of the isotopes used for this purpose are uranium-238, uranium-235 and potassium-40, each of which has a half-life of more than a million years.Unfortunately, these elements don't exist in dinosaur fossils themselves.Carbon Dating Another important dating technique is Carbon-14 dating.This is used to date the remains of things that were once living.
By using radiometric dating to determine the age of igneous brackets, researchers can accurately determine the age of the sedimentary layers between them.
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.
All radioactive atoms decay to become a more stable kind of atom.
The original radioactive atom is known as a parent isotope, while the atom produced by the decay process is known as a daughter isotope. For example Uranium-235 and Uranium-238 are both Uranium atoms with the same number of protons, but they have a different number of neutrons.
The extreme temperatures of the magma would just destroy the bones.