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.