Cosmogenic dating methods
These first “geochronology studies” yielded the first “absolute ages” from geologic material, which seemed to indicate that parts of the Earth's crust were hundreds of millions of years old. There is, of course, one radiometric dating method that appears to overcome the vital "zero date problem".
The isochron dating method theoretically overcomes the need to know the initial ratio of parent and daughter isotopes. For now, we will look at those methods that do fall under the above assumptions.
Based on these assumptions he at first suggested an age of the Earth of between 100 Ma and 500 Ma.
Some, like Robert Gentry, have even argued that Radio-halos from rapidly decaying radioactive isotopes in granite seem to indicate that the granites were formed almost instantly.Other factors and basic assumptions must also be considered.Of course, Kelvin formed his estimates of the age of the Sun without the knowledge of fusion as the true energy source of the Sun.Of course, later scientists, like John Perry and T. After this came to light, Kelvin admitted that he might just as well have set his original upper limit on the age of the Earth at 4,000 Ma instead of 400 Ma.Of course, this was a close as Kelvin ever came to publicly recanting his position.