Editing Radiometric dating (section)

===Closure temperature===
{{Main|Closure temperature}}

The closure temperature or blocking temperature represents the temperature below which the mineral is a closed system for the studied isotopes. If a material that selectively rejects the daughter nuclide is heated above this temperature, any daughter nuclides that have been accumulated over time will be lost through [[diffusion]], resetting the isotopic "clock" to zero. As the mineral cools, the crystal structure begins to form and diffusion of isotopes is less easy. At a certain temperature, the crystal structure has formed sufficiently to prevent diffusion of isotopes. Thus an igneous or metamorphic rock or melt, which is slowly cooling, does not begin to exhibit measurable radioactive decay until it cools below the closure temperature. The age that can be calculated by radiometric dating is thus the time at which the rock or mineral cooled to closure temperature.<ref name=Faure>{{cite book|first=Gunter |last=Faure |title=Principles and applications of geochemistry: a comprehensive textbook for geology students |publisher=[[Prentice Hall]] |location=[[Englewood Cliffs, New Jersey]] |year=1998 |edition=2nd |isbn=978-0-02-336450-1 |oclc=37783103}}{{Page needed|date=September 2010}}</ref><ref name=Rollinson>{{cite book|first=Hugh R. |last=Rollinson |title=Using geochemical data: evaluation, presentation, interpretation |publisher=[[Longman]] |location=[[Harlow]] |year=1993 |isbn=978-0-582-06701-1 |oclc=27937350}}{{Page needed|date=September 2010}}</ref> This temperature varies for every mineral and isotopic system, so a system can be [[Closed system|closed]] for one mineral but [[Open system (thermodynamics)|open]] for another. Dating of different minerals and/or isotope systems (with differing closure temperatures) within the same rock can therefore enable the tracking of the thermal history of the rock in question with time, and thus the history of metamorphic events may become known in detail. These temperatures are experimentally determined in the lab by [[Petrology#Branches|artificially resetting sample minerals]] using a high-temperature furnace. This field is known as [[thermochronology]] or thermochronometry.{{Citation needed|date=October 2022}}