Thermochronology in Orogenic Systems

Early in the history of application of the principles of radioactive decay to the dating of geologic materials, researchers found that some mineral-isotopic systems yielded anomalously young apparent ages. At first, it was assumed that these geochronometers were unreliable, but we now know that they provide unique constraints on the temperature-time histories of rocks that, in turn, constrain geodynamic models of Earth evolution. Modern thermochronology can be thought of as a melding of isotope geochronology and geochemical kinetics. Consequently, both topics play important roles in this chapter. Thermochronology has been especially influential in shaping our understanding of orogenic systems, as many of the applications described here demonstrate.