Overview
- Curtin University researchers published U–Pb ages in the journal Geology showing impact‑modified zircon and apatite from North Pole Dome return closely matching dates near 3.02 billion years, which the team says records the time of the asteroid strike.
- The study, reported June 23, used zircon because it resists change over deep time and apatite because it forms in hot fluids, and the two independent mineral clocks produced concordant ages for the same event.
- Some independent scientists including Aaron Cavosie and Alec Brenner dispute the 3.02 Ga interpretation and argue the impact must be no older than about 2.77 Ga based on regional rock correlations and the presence of shatter cones in younger units.
- Key technical disagreement centers on whether the dated minerals record the impact itself or a later hydrothermal or metamorphic fluid event, a problem made harder by the Pilbara’s long and complex geologic history that can reset mineral clocks.
- Resolving the debate will require more sampling, independent lab dates, and tighter field correlation to show the mineral growths are uniquely tied to the impact rather than later fluid activity, and those steps will determine how the finding changes ideas about early Earth and habitats for early life.