The scheme has a range of several hundred thousand years.18.3.6 Radiocarbon Dating Method Radiocarbon dating, or carbon dating, is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to determine the age of carbonaceous materials up to about 60,000 years.Carbon-14 is a radioactive isotope of carbon, with a half-life of 5,730 years, which is very short compared with those above.The mass spectrometer operates by generating a beam of ionized atoms from the sample under test.The ions then travel through a magnetic field, which diverts them into different sampling sensors, known as “Faraday cups“, depending on their mass and level of ionization.
This scheme is used to date old igneous and metamorphic rocks, and has also been used to date lunar samples.
18.3 Modern Dating Methods Radiometric dating has been carried out since 1905, and since then the techniques have been greatly improved and expanded.
Dating can now be performed on samples as small as a billionth of a gram using a mass spectrometer.
The uranium-lead radiometric dating scheme has been refined to the point that the error margin in dates of rocks can be as low as two million years in two-and-a-half billion year rocks.
An error margin of 2–5 % has been achieved on younger Mesozoic rocks.