Closure temperature

In radiometric dating, closure temperature or blocking temperature is an important idea that helps scientists figure out when rocks and minerals formed. It is the temperature at which a mineral cools enough that certain atoms inside it stop moving around. These atoms, called isotopes, can tell us the age of the rock or mineral.

The idea of closure temperature was first explained in a paper by Martin H. Dodson in 1973, and other scientists have added to our understanding since then. Different minerals have different closure temperatures, depending on which atoms are involved.

Scientists can find out the closure temperature in a lab by heating up samples of minerals and then letting them cool. As the mineral cools, its structure changes, and at a certain temperature, the atoms stop moving. This temperature is the blocking temperature, and it tells us when the mineral became a closed system.

Closure temperatures are very useful in geochronology and thermochronology. They help scientists date events and understand how quickly things happened in Earth's past.

Table of values

The following table shows the closure temperatures of some materials. These temperatures are approximations and can change based on more detailed studies of how the minerals behave.

Potassium-argon method

Uranium-lead method

Electron spin resonance dating