Radiometric dating of potassium
In other words, half of the radioactive isotope in a sample would have decayed to Nitrogen-14 (N-14) in just 5,730 years.
C-14 dating of carbon-bearing materials is therefore limited to roughly 50,000 years.
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.
Similarly, annual lake sediments can be used to estimate relative age and conventional interpretation for the Green River varves suggests they have been formed over some 20 million years.Some claim Genesis in particular, and the Bible in general looks mythical from this standpoint.A full discussion of the topic must therefore include the current scientific challenge to the OE concept.Most people accept the current old-earth (OE) age estimate of around 4.6 billion years.This age is obtained from radiometric dating and is assumed by evolutionists to provide a sufficiently long time-frame for Darwinian evolution.The crucial point here is: if YE theory can be established scientifically, then macroevolutionary theory falls!Accepted Dating Methods Here we outline some dating methods, both absolute and relative, that are widely accepted and used by the scientific community.The time required for half the original number of parent atoms to decay is called the half life.Some half-lives are listed below: It follows that uranium-lead, potassium-argon (K-Ar), and Rubidium-Strontium (Rb-Sr) decay can be used for very long time periods, whilst radiocarbon dating can only be used up to about 70,000 years. This uses a simple exponential decay formula linking the original number, Po, of parent atoms in rocks and minerals to the P atoms now present, thereby enabling an estimate of geological age.Mathematically, P = Po exp(-lambda T), where lambda = the decay constant and T = the period of decay. a zero initial number of D atoms, where P(or D) = the current number of P(or D) atoms, it follows that the age of a rock or mineral is computed as T=(1/lambda)ln(1 D/P).Using radiometric techniques, the oldest dated minerals (4.0 - 4.2 billion years) are zircon crystals found in sedimentary rocks in western Australia.