Scientists reported on 29 October 2026 that ice cores from Tibet’s Guliya Plateau may preserve a climate record extending beyond 128,000 years. The finding extends the known glacial record from the region by more than 100,000 years. The study was led by Lonnie Thompson of the Byrd Polar Research Center at The Ohio State University.
Dating the Guliya ice
Researchers compared cores collected in 1992 and 2015. Both showed similar oxygen-isotope patterns, which scientists use to reconstruct past environmental conditions. The team also used radioactive isotopes of beryllium and chlorine to identify evidence of the Leschamp Geomagnetic Excursion, an event more than 41,000 years ago. Comparisons with oxygen-isotope records from nearby Tibetan cave deposits supported the proposed timeline.
Earlier research had placed the Guliya record only as far back as the middle of the Holocene. The new evidence suggests that some ice is far older. The finding makes Guliya the oldest mountain ice record identified outside the polar regions; ice records from Peru’s Huascarán extend back about 30,000 years. The study appeared in Science Advances in late September or early October 2026.
Important Facts for Exams
- Ice–gas chronologies: An ice core has separate age chronologies for the ice itself and for gases trapped within it.
- Radioactive dating: Radioactive elements can date ice layers; they may occur naturally or result from nuclear testing.
- Geomagnetic time marker: The Laschamp event was a brief reversal of Earth’s magnetic field, dated to between 42,200 and 41,500 years ago.
