Non radiometric dating methods updating palm web browers
Radioactive parent (P) atoms decay to stable daughter (D) atoms e.g.
the carbon isotope C-14 decays to nitrogen-14 and the uranium isotope U-235 decays to the lead isotope Pb-207.
Using radiometric techniques, the oldest dated minerals (4.0 - 4.2 billion years) are zircon crystals found in sedimentary rocks in western Australia.
One early approach was based upon ocean salinity [John Joly, 1800's].
This assumed the ocean was initially pure water and that it's salinity was derived from continental erosion.
One problem with earth dating is that the original earth surface is assumed to have eroded long ago.
But assuming the earth was formed at the time of the rest of our solar system, then recovered moon rock and meteorites can also be used to estimate the age of the earth.