Range of potassium argon dating

Willard Libby invented the carbon dating technique in the early 1950's.The amount of carbon 14 in the atmosphere today (about .0000765%), is assumed there would be the same amount found in living plants or animals since the plants breath CO2 and animals eat plants. Since sunlight causes the formation of C-14 in the atmosphere, and normal radioactive decay takes it out, there must be a point where the formation rate and the decay rate equalizes. Let me illustrate: If you were trying to fill a barrel with water but there were holes drilled up the side of the barrel, as you filled the barrel it would begin leaking out the holes.This is why most people say carbon dating is only good for objects less than 40,000 years old.

range of potassium argon dating-21

Shortly after Becquerel's find, Marie Curie, a French chemist, isolated another highly radioactive element, .

The realisation that radioactive materials emit rays indicated a constant change of those materials from one element to another.

This radioactive carbon 14 slowly decays back into normal, stable nitrogen.

Extensive laboratory testing has shown that about half of the C-14 molecules will decay in 5730 years. After another 5730 years half of the remaining C-14 will decay leaving only ¼ of the original C-14. In theory it would never totally disappear, but after about 5 half lives the difference is not measurable with any degree of accuracy.

Radiometric dating or radioactive dating is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.

The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay.

Radiation from the sun strikes the atmosphere of the earth all day long.

This energy converts about 21 pounds of nitrogen into radioactive carbon 14.

and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of the Earth itself, and can also be used to date a wide range of natural and man-made materials.

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