Ar–ar and k–ar dating

Abstract

The Ar–Ar method has largely superseded conventional K–Ar dating because of its numerous advantages. The presence of K-bearing minerals in a variety of rocks has led to the widespread application of Ar–Ar dating to solve a variety of geological problems involving the geological time scale, hominid evolution, structural geology and tectonics, economic geology, detrital provenance, paleomag-netism, the evolution of sedimentary basins, and the origin of extraterrestrial materials. Moreover, the strong relationship between argon mobility and temperature makes the Ar–Ar method an ideal thermochronometer. To apply it successfully, however, knowledge of the microstructural, mineralogical, petrological, and geological context of the dated samples must be known in order to obtain meaningful interpretations of the age data. With this information, the real power of the Ar–Ar method lies in its unique ability to solve diverse problems in the earth sciences and to elucidate a significant portion of the temperature–time histories of geological terranes.