Argon isotope dating
Potassium, an alkali metal, the Earth's eighth most abundant element is common in many rocks and rock-forming minerals.The quantity of potassium in a rock or mineral is variable proportional to the amount of silica present.Therefore, unlike the conventional K/Ar technique, absolute abundances need not be measured.Instead, the ratios of the different argon isotopes are measured, yielding more precise and accurate results.Radiometric dating has been used to determine the ages of the Earth, Moon, meteorites, ages of fossils, including early man, timing of glaciations, ages of mineral deposits, recurrence rates of earthquakes and volcanic eruptions, the history of reversals of Earth's magnetic field, and many of other geological events and processes.The isotopes the KAr system relies on are Potassium (K) and Argon (Ar).Because it is present within the atmosphere, every rock and mineral will have some quantity of Argon.
Mechanical crushing is also a technique capable of releasing argon from a single sample in multiple steps.
The monitor flux can then be extrapolated to the samples, thereby determining their flux.
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.
These reactor produced isotopes of argon must be corrected for in order to determine an accurate age.
The monitoring of the interfering reactions is performed through the use of laboratory salts and glasses.