(Creationists claim that argon escape renders age determinations invalid.However, any escaping argon gas would lead to a determined age younger, not older, than actual.Strontium-86 is a stable element that does not undergo radioactive change.
The decrease in the amount of potassium required to form the original mineral has consistently confirmed the age as determined by the amount of argon formed.Carbon-14 dating: See Carbon 14 Dating in this web site.The corresponding half lives for each plotted point are marked on the line and identified.It can be readily seen from the plots that when this procedure is followed with different amounts of Rb87 in different minerals, if the plotted half life points are connected, a straight line going through the origin is produced. The steeper the slope of the isochron, the more half lives it represents.(Note that this does not mean that the ratios are the same everywhere on earth.
It merely means that the ratios are the same in the particular magma from which the test sample was later taken.) As strontium-87 forms, its ratio to strontium-86 will increase.
Radioactive elements "decay" (that is, change into other elements) by "half lives." If a half life is equal to one year, then one half of the radioactive element will have decayed in the first year after the mineral was formed; one half of the remainder will decay in the next year (leaving one-fourth remaining), and so forth.
The formula for the fraction remaining is one-half raised to the power given by the number of years divided by the half-life (in other words raised to a power equal to the number of half-lives).
The sum of protons plus neutrons is the mass number.
We designate a specific group of atoms by using the term "nuclide." A nuclide refers to a group of atoms with specified atomic number and mass number.
The creationist "argon escape" theory does not support their young earth model.) The argon age determination of the mineral can be confirmed by measuring the loss of potassium.