Overview
- Researchers led by Carolyn Crow of the University of Colorado Boulder report in Geology that the lunar meteorite Northwest Africa 12593 preserves a record of a very high‑temperature impact roughly 3.486 billion years ago.
- Analyses of 21 baddeleyite grains show traces of cubic zirconia phases that form only at temperatures above about 2,370°C, indicating the impact melted and recrystallized lunar rock at extreme heat.
- The meteorite records three sequential events: the ancient high‑temperature melting, a later breccia‑forming impact that mixed rock fragments, and a much later collision that ejected the fragment to Earth.
- The 3.486 Ga age aligns with separate impact markers found in Australia, South Africa, and on the asteroid Vesta, which together support a prolonged period of elevated bombardment after the classical Late Heavy Bombardment window.
- Beyond dating impacts, the finding highlights the value of lunar meteorites for sampling unexplored Moon regions and prompts follow‑up work to locate the source crater and to study how such impacts may have affected early Earth environments and habitability.