According to a recent article published in Science, the Colorado
River began to cut its course through the Grand Canyon 17
million years ago. The authors base their claim on radiometric
dating of cave formations found in the canyon walls. Their
method, a type of radiometric dating called uranium-lead (U-Pb)
dating, relies on the fact that uranium isotopes radioactively
decay to form lead isotopes. By comparing the amount of each
isotope in a sample, the age of the sample can be calculated.1
Radiometric dating not only supports the geologic "evolution" of
the Grand Canyon, it validates a central tenet in a much
different theory of evolution - a theory introduced by Charles
Robert Darwin in his 1859 publication, On the Origin of Species
by Means of Natural Selection, or the Preservation of Favoured
Races in the Struggle for Life: - "I am fully convinced that
species are not immutable; but that those belonging to what are
called the same genera are lineal descendants of some other and
generally extinct species,