Our ability to interpret and understand geologic events has been significantly enhanced by the development of various tools which allow us to determine the absolute age of many rocks and/or minerals.There are several different techniques and approaches possible, but all rely on the principles of radioactive decay of unstable isotopes of elements present in trace quantities in many rocks and minerals.
These are often characterised as the norm, rather than the exception.
I thought it would be useful to present an example where the geology is simple, and unsurprisingly, the method does work well, to show the quality of data that would have to be invalidated before a major revision of the geologic time scale could be accepted by conventional scientists.
In 1905, shortly after the discovery of radioactivity, the American chemist Bertram Boltwood suggested that lead is one of the disintegration products of uranium, in which case the older a uranium-bearing mineral the greater should be its proportional part of lead.
Analyzing specimens whose relative geologic ages were known, Boltwood found that the ratio of lead to uranium did indeed increase...
As an example, consider Carbon: All atoms of Carbon consist of 6 protons and 6 electrons.