Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! Isochron dating can be further separated into ; both techniques are applied frequently to date terrestrial and also extraterrestrial rocks (meteorites).

Isochron dating is a common technique of radiometric dating and is applied to date certain events, such as crystallization, metamorphism, shock events, and differentiation of precursor melts, in the history of rocks.

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The advantage of isochron dating as compared to simple radiometric dating techniques is that no assumptions are needed about the initial amount of the daughter nuclide in the radioactive decay sequence.

Indeed the initial amount of the daughter product can be determined using isochron dating.

It is also useful to determine the time of metamorphism, shock events (such as the consequence of an asteroid impact) and other events depending of the behaviour of the particular isotopic systems under such events.

Wiens has a Ph D in Physics, with a minor in Geology.

The greater the initial concentration of the parent, the greater the concentration of the radiogenic daughter isotope will be at some particular time.

Thus, the ratio of the daughter to non-radiogenic isotope will become larger with time, while the ratio of parent to daughter will become smaller.Ratios are used instead of absolute concentrations because mass spectrometers usually measure the former rather than the latter.(See particularly the section on isotope ratio mass spectrometry.) If all data points lie on a straight line, this line is called an isochron.For rocks that start out with a small concentration of the parent, the daughter/non-radiogenic ratio will not change quickly as compared to rocks starting with a large concentration of the parent.To perform mineral isochron dating, a rock is separated into several different minerals with different ratios between parent and daughter concentrations.Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers.