Argon loss occurs when radiogenic K by a fast neutron reaction) can be used as a proxy for potassium.Therefore, unlike the conventional K/Ar technique, absolute abundances need not be measured.This flux is known as the 'J' and can be determined by the following equation: As the table above illustrates, several "undesirable" reactions occur on isotopes present within every geologic sample.
The NMGRL does this by irradiating samples in machined aluminum disks where standards and unknowns alternate every other position.
Traditionally, this primary standard has been a hornblende from the Mc Clure Mountains, Colorado (a.k.a. Once an accurate and precise age is determined for the primary standard, other minerals can be dated relative to it by the Ar technique (e.g. However, while it is often easy to determine the age of the primary standard by the K/Ar method, it is difficult for different dating laboratories to agree on the final age.
Likewise, because of heterogeneity problems with the MMhb-1 sample, the K/Ar ages are not always reproducible.
Argon can mobilized into or out of a rock or mineral through alteration Ar and potassium, there is not a reliable way to determine if the assumptions are valid.
Argon loss and excess argon are two common problems that may cause erroneous ages to be determined.