For example, by using a laser, researchers can measure parent and daughter atoms in extremely small amounts of matter, making it possible to determine the age of very small samples [source: New Scientist].Igneous rocks are those that form via the process of melting and cooling.The extreme temperatures of the magma would just destroy the bones.So to determine the age of sedimentary rock layers, researchers first have to find neighboring layers of Earth that include igneous rock, such as volcanic ash.(more below)Click the photo to see the full-size version.
Andesite is considered the extrusive equivalent of diorite.
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.
The most widely known form of radiometric dating is carbon-14 dating.
This is what archaeologists use to determine the age of human-made artifacts. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old.
Each of them typically exists in igneous rock, or rock made from cooled magma.