The U-series decay chains contain many elements that can be fractionated in environmental and geological processes.
Half-lives of radioactive isotopes of such elements range from seconds to many millennia and application depends on the natural timeframe of the process or the elapsed time.
Even though it decays into nitrogen, new carbon-14 is always being formed when cosmic rays hit atoms high in the atmosphere.
Plants absorb carbon dioxide from the atmosphere and animals eat plants.
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.
U at the time of sample formation must be known or calculated.
With time, Thorium 230 accumulates in the sample through radiometric decay.
If half of the uranium-238 has turned into lead-206 the rock will be 4500 million years old. The contributions of uranium/thorium and marine palynology to the dating of the Lake Wangoom pollen record, western plains of Victoria, Australia. 230Th/234U and 14C dating of a late Pleistocene stalagmite in Lobatse II cave, Botswana. Atmospheric radiocarbon calibration beyond 11,900 cal BP from Lake Suigetsu. Mass-spectrometric 230Th-234U-238U dating of the Devils Hole calcite vein.
Uranium series dating of impure carbonates: an isochron technic using total sample dissolution.