Closure temperature
In radiometric dating, closure temperature or blocking temperature refers to the temperature of a system, such as a mineral, at the time given by its radiometric date. In physical terms, the closure temperature is the temperature at which a system has cooled so that there is no longer any significant diffusion of the parent or daughter isotopes out of the system and into the external environment. The concept's initial mathematical formulation was presented in a seminal paper by Martin H. Dodson, "Closure temperature in cooling geochronological and petrological systems" in the journal "Contributions to Mineralogy and Petrology