Paleomagnetic dating absolute
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.
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.
Using the basic ideas of bracketing and radiometric dating, researchers have determined the age of rock layers all over the world.
This information has also helped determine the age of the Earth itself.
In addition, the oldest known moon rocks are 4.5 billion years old.
Fossils can't form in the igneous rock that usually does contain the isotopes.You may find it useful for the clear definitions, and for excellent links on a variety of topic.Many of these links also appear where appropriate below.Chronological sequence is all that is really required.However, human beings love to see factual precision, and we want to know how old something is.