Jack Hills zircon

Jack Hills zircons are ancient zircon crystals found in Western Australia, including grains dated to about 4.4 billion years ago, the oldest known terrestrial minerals.

Uranium–lead dating: A radiometric dating method that uses the decay of uranium isotopes into lead isotopes. Uranium–lead measurements established the great age of Jack Hills zircon grains.
Zircon: A zirconium silicate mineral, ZrSiO₄, that commonly incorporates uranium and resists chemical alteration. Jack Hills grains are examples of this durable mineral, whose properties preserve their records.
Jack Hills: A range in Western Australia whose sedimentary rocks contain abundant ancient detrital zircon grains. These rocks are the source locality that gave the zircon population its name.
Hadean ocean: A proposed body of liquid water on Earth during the Hadean eon. Oxygen-isotope evidence from some grains has been used to argue that surface water existed early.
Oxygen isotope ratio: The relative abundance of oxygen isotopes in a material, used to infer its formation conditions and history. Zircon oxygen isotopes provide evidence that some source rocks interacted with liquid water.
Radioactive decay: The spontaneous transformation of unstable atomic nuclei into more stable nuclei, releasing radiation. Uranium decay supplies the clock used to date the zircon crystals.
4.4-billion-year-old zircon: A Jack Hills zircon grain dated to about 4.4 billion years ago, near the oldest accepted terrestrial mineral ages. It exemplifies the extreme antiquity that made the grains central to early-Earth research.
Hadean habitability: The potential for Hadean environments to support conditions suitable for life. Evidence for early water raises questions about when habitable environments first appeared.
Hadean Earth: The earliest interval of Earth history, extending from its formation about 4.54 billion years ago to roughly 4 billion years ago. The oldest Jack Hills grains offer rare direct evidence from this otherwise poorly preserved eon.
Isotope: One of two or more forms of an element with the same proton count but different neutron counts. Isotopic differences make both the age measurements and environmental clues possible.

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