Overview
- Published October 28 in PNAS, the COLDEX collaboration reports ice and air from East Antarctica directly dated to roughly 6 million years.
- Oxygen‑isotope data from the samples provide the first direct estimate of long‑term regional cooling, about 12°C over that span.
- The team dated the ice by analyzing an argon isotope in tiny air bubbles, enabling ages to be determined from the ice itself.
- Shallow drilling 100–200 meters at Allan Hills recovered discontinuous cores that extend climate information about six times older than prior ice‑core records, contrasting with >2,000‑meter deep continuous cores elsewhere.
- Researchers plan additional Allan Hills campaigns in the coming months and a longer study targeted for 2026–2031 to seek older ice and reconstruct ancient greenhouse gases and ocean heat content.