Anyone questioning the accuracy of radiometric methods is obliged to explain why the cross-checks to sediments, coral growth, tree rings, and other isotope pairs all have the same errors.
Why would an error in radiometric dating correspond to errors in the other methods so that they all track?
Argon/argon dating works using only the ratio of the concentration of the argon isotopes. For the purposes of this debate, "accurate" means that 95% of the dating errors are within 10% of the measured date, within the time span for which the isotope pair is utilized.
Since carbon dating depends upon variable cosmic ray intensity, a calibration curve is assumed to be applied to account for that.
Thus the physical principle of the method is well established. The dates obtained by radiometric dating are verified by independent methods, including dendrochronology (tree rings), varve chronology (sediment layers), ice cores, coral banding, speleotherms (cave formations), fission track dating, and electron spin resonance dating.
After a long enough time the minority isotope is in an amount too small to be measured.
Radiometric dating is the method for establishing the age of objects by measuring the levels of radioisotopes in the sample. It decays to nitrogen 14 with a half life of 5730 years.
Carbon 14 is created by cosmic rays in the upper atmosphere.
In fact, they track because radiometric data is accurate.
An expert scientist summarizes: "The first radiometric dates, generated about 1920, showed that the Earth was hundreds of millions, or billions, of years old.