Dating mesure com
The relatively short half-life of carbon-14, 5,730 years, makes dating reliable only up to about 50,000 years.The technique often cannot pinpoint the date of an archeological site better than historic records, but is highly effective for precise dates when calibrated with other dating techniques such as tree-ring dating.
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.
Argon, a noble gas, is not commonly incorporated into such samples except when produced in situ through radioactive decay.
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.
Thus dating that particular tree does not necessarily indicate when the fire burned or the structure was built.
For this reason, many archaeologists prefer to use samples from short-lived plants for radiocarbon dating.
This technique is based on the principle that all objects absorb radiation from the environment.