Sentence using relative dating
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.One of the most widely used is potassium–argon dating (K–Ar dating).Potassium-40 is a radioactive isotope of potassium that decays into argon-40.The half-life of potassium-40 is 1.3 billion years, far longer than that of carbon-14, allowing much older samples to be dated.Potassium is common in rocks and minerals, allowing many samples of geochronological or archeological interest to be dated.Argon, a noble gas, is not commonly incorporated into such samples except when produced in situ through radioactive decay.
Particular isotopes are suitable for different applications due to the types of atoms present in the mineral or other material and its approximate age.Carbon-14 moves up the food chain as animals eat plants and as predators eat other animals. It takes 5,730 years for half the carbon-14 to change to nitrogen; this is the half-life of carbon-14.After another 5,730 years only one-quarter of the original carbon-14 will remain.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.Carbon-14 is continually formed in nature by the interaction of neutrons with nitrogen-14 in the Earth’s atmosphere; the neutrons required for this reaction are produced by cosmic rays interacting with the atmosphere.