Web edition: November 16, 2012 Print edition: December 1, 2012;
Vol.182 #11 (p. 4) NEW DATING METHOD FOR MILLION-YEAR-OLD
FOSSILS — A new radioactive dating method promises to close one
of the major remaining gaps in methods of fixing dates on the
geological and archaeological time scales. The new procedure,
based on radioactive inequality in nature between uranium-234
and its parent U-238, was originated by David Turber of
Columbia’s Lamont Geological Observatory at Palisades, N.Y. The
research is described in the Journal of Geophysical Research,
Nov. 1962. Uranium-234 is an isotope of uranium formed by the
radioactive decay of U-238. The “disequilibrium” between the two
isotopes possibly can be employed to date sedimentary material —
which often contains fossils — as old as 1 million to 1.5
million years.