The abundance and variety of fossils in Phanerozoic rocks have allowed geologists to decipher in considerable detail the past 600 million years or so of the Earth’s history.
Before reviewing briefly the evidence for the age of the Earth, I emphasize that the formation of the Solar System and the Earth was not an instantaneous event but occurred over a finite period as a result of processes set in motion when the universe formed.
It is, therefore, more correct to talk about formational intervals rather than discrete ages for the Solar System and the Earth.
A particularly fascinating question about the history of the Earth is “When did the Earth begin?
” The answer to this question was provided by radiometric dating and is now known to within a few percent.
This method is thought to represent the time when lead isotopes were last homogeneously distributed throughout the Solar System and, thus, the time that the planetary bodies were segregated into discrete chemical systems.