Define absolute dating of fossils
The development of accelerator mass spectrometry (AMS) dating, which allows a date to be obtained from a very small sample, has been very useful in this regard.Other radiometric dating techniques are available for earlier periods.It cannot be used to accurately date a site on its own.
The date measured reveals the last time that the object was heated past the closure temperature at which the trapped argon can escape the lattice.
K–Ar dating was used to calibrate the geomagnetic polarity time scale.
Thermoluminescence testing also dates items to the last time they were heated.
Heating an item to 500 degrees Celsius or higher releases the trapped electrons, producing light.
This light can be measured to determine the last time the item was heated. Fluctuating levels can skew results – for example, if an item went through several high radiation eras, thermoluminescence will return an older date for the item.