Different types dating techniques used archaeology
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.After yet another 5,730 years only one-eighth will be left.By measuring the carbon-14 in organic material, scientists can determine the date of death of the organic matter in an artifact or ecofact.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.
Thermoluminescence testing also dates items to the last time they were heated.This is a radiometric technique since it is based on radioactive decay.Cosmic radiation entering the earth’s atmosphere produces carbon-14, and plants take in carbon-14 as they fix carbon dioxide.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.
Techniques include tree rings in timbers, radiocarbon dating of wood or bones, and trapped-charge dating methods such as thermoluminescence dating of glazed ceramics.