accommodating iol synchrony - What is uranium 235 dating
) can use only the readily fissionable but scarce isotope uranium-235 for fuel, a breeder reactor employs either uranium-238 or thorium, of which sizable quantities are available. The principal fissile materials are uranium-235 (0.7 percent of naturally occurring uranium), plutonium-239, and uranium-233, the last two being artificially produced from the fertile materials uranium-238 and thorium-232, respectively.
Uranium-238, for example, accounts for more than 99 percent of all naturally occurring uranium. A fertile material, not itself capable of undergoing fission with low-energy neutrons, is one that decays into fissile material after neutron absorption...
Uranium-lead dating uses four different isotopes to find the age of the rock.
The four isotopes are uranium-235, uranium-238, lead-207, and lead-206.
Currently, palaeontologists date dinosaur fossils by a method called relative chronology, estimating the age of a fossil relative to the known depositional age of the sedimentary rock in which it was found.
However, such methods are far from perfect: it is difficult to gain accurate depositional ages for sedimentary rocks, and matters can be further complicated when millions of years of geologic and environmental forces cause erosion of fossil-bearing strata.
A team led by Larry Heaman of the University of Alberta's Department of Earth and Atmospheric Sciences used the method to determine the age of the fossilised femur of a sauropod, a herbivorous dinosaur.