This can reduce the problem of contamination.
How Carbon-14 Dating Works
The result of this is to supply streams, rivers, and lakes with a source of dissolved calcium carbonate ; if freshwater shellfish for example use this to construct their shells, then they are using a source of carbon which is millions of years old. After irradiation, samples are heated in a series of steps and the xenon isotopic signature of the gas evolved in each step is analysed. Thus an igneous or metamorphic rock or melt, which is slowly cooling, does not begin to exhibit measurable radioactive decay until it cools below the closure temperature. By using radiometric dating to determine the age of igneous bracketsresearchers can accurately determine the age of the sedimentary layers between them. This can be seen in the concordia diagram, where the samples plot along an errorchron straight line which intersects the concordia curve at the age of the sample.