The main thing is that it's consistent with other forms of dating. The iodine-xenon chronometer  is an isochron technique. Geochronologists do not reliable is a major contention of a radiometric dating is the most common form of atoms of which to three unprovable. For example, for 1 die the numbers can range from 1 to 6, and the standard deviation is about 1. On a normal distribution, 8 s.
Radiometric Dating and the Geological Time Scale:
Asteroids in the solar system have been clocked at 4. Other events on earth can be dated equally well given the right minerals. One of its great advantages is that any sample provides two clocks, one based on uranium's decay to lead with a half-life of about million years, and one based on uranium's decay to lead with a half-life of about 4. However, local eruptions of volcanoes or other events that give off large amounts of carbon dioxide can reduce local concentrations of carbon and give inaccurate dates. 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. The disintegration products of uranium".