Thorium uranium dating
However, use of a single decay scheme (usually Pb) leads to the U–Pb isochron dating method, analogous to the rubidium–strontium dating method.
Finally, ages can also be determined from the U–Pb system by analysis of Pb isotope ratios alone. Clair Cameron Patterson, an American geochemist who pioneered studies of uranium–lead radiometric dating methods, used it to obtain one of the earliest estimates of the age of the Earth.
Fission tracks and micro-cracks within the crystal will further extend this radiation damage network.
These fission tracks act as conduits deep within the crystal, providing a method of transport to facilitate the leaching of lead isotopes from the zircon crystal.
Uranium series dating of impure carbonates: an isochron technic using total sample dissolution.
A large drop in atmospheric 14C/12C and reduced melting in the Younger Dryas, documented with 230Th ages of corals.
Calibration of the 14C timescale over the past 30,000 years using mass spectrometric U-Th ages from Barbados corals.
The sample age is based on the difference between the initial ratio of U with the environment (i.e., that it is a closed system.) The method is used for samples that can retain Uranium and Thorium, such as carbonate sediments, bones and teeth.
Ages between 1000 and 300,000 years have been reported.
Uranium/Thorium dating of ferricretes from mid- to late Pleistocene glacial sediments, western Tasmania, Australia.
500 ka precipitation record from southeastern Australia: evidence for interglacial relative aridity.