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In recent decades, many techniques have been developed for the purpose of producing more accurate and refined age dates. Of these, the most significant has been the evolution of40Ar/39Ar dating methods which compare the ratios of these two argon isotopes from a small portion of a sample to avoid the inaccuracies inherent in inhomogeneous samples such as whole rocks, parts of which may not be representative. In this method, the sample and a standard of known age containing potassium‐40 are bombarded with neutrons in a nuclear reactor to produce argon‐39 which does not exist naturally. The amount of argon‐39 produced under a standard set of conditions is a proxy for the amount of potassium‐40 in the sample. From this information, the40K/40Ar ratio can be calculated and the age of the sample determined. On the whole,40Ar/39Ar dating methods appear to be more accurate than conventional40K/40Ar40 methods and can date samples as young as 25 Ka, but they do require access to a nuclear reactor.