Secondly, K-Ar dating assumes that very little or no argon or potassium was lost from the mineral since it formed. it does not bond to any other elements), it can readily escape from minerals if they are exposed to significant amounts of heat for a prolonged period of time.Finally—and perhaps most importantly—the K-Ar dating method assumes that we can accurately measure the ratio between 40K and 40Ar.K-Ar dating method sometimes can mislead us, for example Kilauea Iki basalt, Hawaii (A. 1959) dating age are 8.5±6.8 Ma (Krummenacher, 1970).
While this assumption holds true in the vast majority of cases, excess argon can occasionally be trapped in the mineral when it crystallizes, causing the K-Ar age to be a few hundred thousand to a few million years older than the actual cooling age.This relationship is useful to geochronologists, because quite a few minerals in the Earth’s crust contain measurable quantities of potassium (e.g. In theory, therefore, we can estimate the age of the mineral simply by measuring the relative abundances of each isotope.Over the past 60 years, potassium-argon dating has been extremely successful, particularly in dating the ocean floor and volcanic eruptions.I emphasize this assumption, because it is so commonly overlooked by those unfamiliar with radiometric dating!
K-Ar ages away from spreading ridges, just as we might expect, and recent volcanic eruptions yield very young dates, while older volcanic rocks yield very old dates.Though we know that K-Ar dating works and is generally quite accurate, however, the method does have several limitations.