Closure temperature radiometric dating
It is more accurate for shorter time periods (e.g., hundreds of years) during which control variables are less likely to change.There are a number of implausible assumptions involved in radiometric dating with respect to long time periods.One key assumption is that the initial quantity of the parent element can be determined.With uranium-lead dating, for example, the process assumes the original proportion of uranium in the sample.This temperature varies broadly between different minerals and also differs depending on the parent and daughter atoms being considered.These temperatures are experimentally determined in the lab by artificially resetting sample minerals using a high-temperature furnace.The age that can be calculated by radiometric dating is thus the time at which the rock or mineral cooled to blocking temperature.
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.
Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! In physical terms, the closure temperature at which a system has cooled so that there is no longer any exchange of parent or daughter isotopes with the external environment.
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.
At a certain temperature, the crystal structure has formed sufficiently to prevent diffusion of isotopes.
This temperature is what is known as blocking temperature and represents the temperature below which the mineral is a closed system to measurable diffusion of isotopes.