When a rock undergoes metamorphism, some or all of its argon can be outgassed.If all the argon was lost, this would reset the K-Ar clock to zero, and dating the rock would give us the time of metamorphism; and if we recognized the rock as metamorphic this would actually be quite useful.But consider what happens if the argon came from deep within the Earth, where it was formed by Ar ratio as is found in the atmosphere, and the formula that corrects for atmospheric carbon will not correct for this.Finally, we must consider the possibility of argon loss.Potassium–Argon dating or K–Ar dating is a radiometric dating method used in geochronology and archaeology.It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar).Ca/K) information can be obtained from each sample.The WAAIF is equipped with A MAP215-50 mass spectrometer with a low-blank automated extraction system coupled with a New Wave Nd-YAG dual IR (1064 nm) and UV (216 nm) laser, an electromuliplier detector and Niers source.
Still, as a general rule, the proportional error in K-Ar dating will be greatest in the youngest rocks.
The 213 nm ultra-violet laser is capable of high-resolution (up to 10 µm beam size) ablation of any mineral, allowing detailed analysis of individual mineral grains.
The infra-red laser (continuous wavelength 60W 1064 nm Nd-YAG) is capable of spot analysis (100-300 µm spot size), single grain total fusion, and incremental laser step-heating of K-rich minerals and whole rocks.
dating method is used to measure the age and timing of a large variety of geological processes, from meteorite samples as old as the Earth (4.5 billion years) to the age of historical events such as the Vesivius eruption (79 AD).
The Ar technique can be applied to any rocks and minerals that contain K (e.g. method is also used to date a myriad of other geological events such as volcanism, tectonic plate movements, mountain building rates, sediment formation, weathering and erosion, hydrothermal fluid movements, and alteration and diagenesis of minerals. The main advantage of Ar-Ar dating is that it allows much smaller samples to be dated, and more age and composition (e.g.
Argon, on the other hand, is an inert gas; it cannot combine chemically with anything.