Relative dating vs numerical dating
This technique is based on the principle that all objects absorb radiation from the environment.This process frees electrons within minerals that remain caught within the item.It cannot be used to accurately date a site on its own.However, it can be used to confirm the antiquity of an item.An additional problem with carbon-14 dates from archeological sites is known as the "old wood" problem.It is possible, particularly in dry, desert climates, for organic materials such as from dead trees to remain in their natural state for hundreds of years before people use them as firewood or building materials, after which they become part of the archaeological record.
Other radiometric dating techniques are available for earlier periods.
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.
For example, techniques based on isotopes with half lives in the thousands of years, such as Carbon-14, cannot be used to date materials that have ages on the order of billions of years, as the detectable amounts of the radioactive atoms and their decayed daughter isotopes will be too small to measure within the uncertainty of the instruments.
One of the most widely used and well-known absolute dating techniques is carbon-14 (or radiocarbon) dating, which is used to date organic remains.