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.
Radiometric dating of rocks and minerals using naturally occurring, long-lived radioactive isotopes is troublesome for young-earth creationists because the techniques have provided overwhelming evidence of the antiquity of the earth and life.
Some so-called creation scientists have attempted to show that radiometric dating does not work on theoretical grounds (for example, Arndts and Overn 1981; Gill 1996) but such attempts invariably have fatal flaws (see Dalrymple 1984; York and Dalrymple 2000).
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.
The purpose of this paper is to describe briefly a few typical radiometric dating studies, out of hundreds of possible examples documented in the scientific literature, in which the ages are validated by other available information.
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.I could have selected many more examples but then this would have turned into a book rather than the intended short paper.The Manson Meteorite Impact and the Pierre Shale In the Cretaceous Period, a large meteorite struck the earth at a location near the present town of Manson, Iowa.Other creationists have focused on instances in which radiometric dating seems to yield incorrect results.