Do Radioisotope Clocks Need Repair? Testing the Assumptions of
Isochron Dating Using K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb Isotopes by
Steven A. Austin, Ph.D. RATE II: Radioisotopes and the Age of
The Earth: Results of a Young-Earth Creationist Research
Initiative, (Volume II), L. Vardiman et al., eds. (San Diego,
CA: Institute for Creation Research and the Creation Research
Society, 2005) The assumptions of conventional whole-rock and
mineral isochron radioisotope dating were tested using a suite
of radioisotopes from two Precambrian rocks. Amphibolite from
the Beartooth Mountains of Wyoming shows evidence of thorough
metamorphism by isochemical processes from andesite by an early
Precambrian magma-intrusion event. A diabase sill, exposed
within the wall of Grand Canyon at Bass Rapids, formed by a
rapid intrusion event. The event segregated minerals
gravitationally, apparently starting from an isotopically
homogeneous magma. Although K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb
methods ought to yield concordant isochron dates for