|Title:||Extinct 244Pu in ancient zircons|
|Authors:||G. Turner, T.M. Harrison, G. Holland, S.J. Mojzsis, and J. Gilmour|
|Publication:||Science, v. 306, p. 89‐91.|
We have found evidence, in the form of fissiogenic xenon isotopes, for in situ decay of 244Pu in individual 4.1‐ to 4.2‐billion‐year‐old zircons from the Jack Hills region of Western Australia. Because of its short half‐life, 82 million years, 244Pu was extinct within 600 million years of Earth’s formation. Detrital zircons are the only known relics to have survived from this period, and a study of their Pu geochemistry will allow us to date ancient metamorphic events and determine the terrestrial Pu/U ratio for comparison with the solar ratio.