Read this Article. This "air correction" relies on the level of argon, which comes only from the air and is not created by any nuclear decay reaction. Radiometric dating. New York, Oxford University Press. Merrihue, C. Hilgen, F. Reynolds, J.
Potassium Argon Dating
Argon makes up 1 percent of the atmosphere. Geochimica et Cosmochimica Acta At the jan 28, Pringle, M. Rock samples are recorded, marked, sealed and kept free of contamination and excessive heat on the way to the lab. The remaining 38 Ar is from the spike, and the remaining 40 Ar is radiogenic.