The equation is most conveniently expressed in terms of the measured quantity N t rather than the constant initial value N o. 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-lifeusually given in units of years when discussing dating techniques. Another example of short-lived extinct radionuclide dating is the 26 Al — 26 Mg chronometer, which can be used to estimate the relative ages of chondrules. The principles of original horizontality, superposition, and cross-cutting relationships allow events to be ordered at a single location. Older materials can be dated using zirconapatitetitaniteepidote and garnet which have a variable amount of uranium content.
They can then look at a single mineral, and using an instrument called a mass spectrometer, they can measure the amount of parent and the amount of daughter in that mineral.
Dating methods like thermoluminescenceoptical stimulating luminescence and electron spin resonancemeasure the accumulation of electrons in these imperfections, or "traps," in the crystal structure of the material. However, there are some factors that must be accounted for. Nuclear Methods of Dating.