Is radiometric dating accurate
The heat of the impact melted some of the feldspar crystals in the granitic rocks of the impact zone, thereby resetting their internal radiometric clocks.
These melted crystals, and therefore the impact, have been dated by the 40Ar/39Ar method at 74.1 Ma (million years; Izett and others 1998), but that is not the whole story by a long shot.
The impact also created shocked quartz crystals that were blasted into the air and subsequently fell to the west into the inland sea that occupied much of central North America at that time.
I have selected four examples from recent literature, mostly studies involving my work and that of a few close colleagues because it was easy to do so.Even things that work well do not work well all of the time and under all circumstances.Try, for example, wearing a watch that is not waterproof while swimming. A few verified examples of incorrect radiometric ages are simply insufficient to prove that radiometric dating is invalid.Other dating techniques, like K-Ar (potassium-argon and its more recent variant 40Ar/39Ar), Rb-Sr (rubidium-strontium), Sm-Nd (samarium-neodynium), Lu-Hf (lutetium-hafnium), and U-Pb (uranium-lead and its variant Pb-Pb), have all stood the test of time.These methods provide valuable and valid age data in most instances, although there is a small percentage of cases in which even these generally reliable methods yield incorrect results.