After one half-life has elapsed, one half of the atoms of the nuclide in question will have decayed into a "daughter" nuclide or decay product.

In many cases, the daughter nuclide itself is radioactive, resulting in a decay chain, eventually ending with the formation of a stable (nonradioactive) daughter nuclide; each step in such a chain is characterized by a distinct half-life.

After an organism has been dead for 60,000 years so little carbon-14 is left that accurate dating can not be established.

On the other hand, the concentration of carbon-14 falls off so steeply that the age of relatively young remains can be determined precisely to within a few decades.

If a material that selectively rejects the daughter nuclide is heated, any daughter nuclides that have been accumulated over time will be lost through diffusion, setting the isotopic "clock" to zero.

The temperature at which this happens is known as the closure temperature or blocking temperature and is specific to a particular material and isotopic system.

In these cases, usually the half-life of interest in radiometric dating is the longest one in the chain, which is the rate-limiting factor in the ultimate transformation of the radioactive nuclide into its stable daughter.

Isotopic systems that have been exploited for radiometric dating have half-lives ranging from only about 10 years (e.g., tritium) to over 100 billion years (e.g., Samarium-147).

While the moment in time at which a particular nucleus decays is unpredictable, a collection of atoms of a radioactive nuclide decays exponentially at a rate described by a parameter known as the half-life, usually given in units of years when discussing dating techniques.Rocks known to have formed in historical times should not yield dates of millions of years.. Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive. Rocks known to have formed in historical times should not yield dates of millions of years.. Therefore, in any material containing a radioactive nuclide, the proportion of the original nuclide to its decay product(s) changes in a predictable way as the original nuclide decays over time.This predictability allows the relative abundances of related nuclides to be used as a clock to measure the time from the incorporation of the original nuclide(s) into a material to the present.

While the moment in time at which a particular nucleus decays is unpredictable, a collection of atoms of a radioactive nuclide decays exponentially at a rate described by a parameter known as the half-life, usually given in units of years when discussing dating techniques.Rocks known to have formed in historical times should not yield dates of millions of years.. Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive. Rocks known to have formed in historical times should not yield dates of millions of years.. Therefore, in any material containing a radioactive nuclide, the proportion of the original nuclide to its decay product(s) changes in a predictable way as the original nuclide decays over time.This predictability allows the relative abundances of related nuclides to be used as a clock to measure the time from the incorporation of the original nuclide(s) into a material to the present.It is therefore essential to have as much information as possible about the material being dated and to check for possible signs of alteration.