Define chronometric dating
Cosmic radiation entering the earth’s atmosphere produces carbon-14, and plants take in carbon-14 as they fix carbon dioxide.
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.
a timepiece or timing device with a special mechanism for ensuring and adjusting its accuracy, for use in determining longitude at sea or for any purpose where very exact measurement of time is required. Chronometers are used in scientific experiments, navigation, and astronomical observations.
It was the invention of a chronometer capable of being used aboard ship, in 1762, that allowed navigators for the first time to accurately determine their longitude at sea.
Other radiometric dating techniques are available for earlier periods.
Scientists first developed absolute dating techniques at the end of the 19th century.
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.
Chronometric dating, also known as chronometry or absolute dating, is any archaeological dating method that gives a result in calendar years before the present time.
Archaeologists and scientists use absolute dating methods on samples ranging from prehistoric fossils to artifacts from relatively recent history.