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Using radiocarbon dating, archaeologists during the past years have been able to obtain a much needed global perspective on the timing of major prehistoric events such as the development of agriculture in various parts of the world.
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Among the significant events that caused a temporary but significant spike in the atmospheric carbon-14 to carbon-12 ratio were above-ground nuclear test detonations in the two decades following World War II.
is a term for radiocarbon dating based on timestamps left by above-ground nuclear explosions, and it is especially useful for putting an absolute age on organisms that lived through those events.
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is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past. To understand radiocarbon dating, you first have to understand the word Although an element’s number of protons cannot change, the number of neutrons can vary slightly in each atom.
Willard Libby at the University of Chicago developed the technique of radiocarbon dating in 1949.
Organisms at the base of the food chain that photosynthesize – for example, plants and algae – use the carbon in Earth’s atmosphere.
They have the same ratio of carbon-14 to carbon-12 as the atmosphere, and this same ratio is then carried up the food chain all the way to apex predators, like sharks.
A raw date cannot be used directly as a calendar date, because the level of atmospheric carbon 14 has not been constant during the span of time that can be radiocarbon dated.
The level is affected by variations in the cosmic ray intensity, which is, in turn, affected by variations in the Earth’s magnetosphere.
In addition, there are substantial reservoirs of carbon in organic matter, the ocean, ocean sediments, and sedimentary rock.