Overview
- A PNAS study details direct argon isotope dating of microscopic air trapped in shallow Allan Hills ice.
- The deepest samples are about 6 million years old, pushing Antarctic ice and atmospheric records far beyond previous cores.
- Oxygen-isotope data show the region was roughly 12°C warmer at that time and cooled gradually to present-day conditions.
- Researchers extracted 150–206 meter cores from blue-ice patches that provide discontinuous climate snapshots rather than a continuous record.
- COLDEX plans additional drilling at Allan Hills soon and a longer campaign targeted for 2026–2031 to find older ice and reconstruct ancient greenhouse gases.