Guliya Cores Dated to 128,000 Years via Beryllium-Chlorine Isotopes Extend Tibetan Record
Matching 1992 and 2015 Guliya cores, dated with cosmogenic isotopes to >128 ka, show Tibetan ice persisted through the last glacial cycle. The extended record challenges Holocene-only assumptions in regional models and supplies the longest non-polar mountain climate archive. Additional deep cores and multi-nuclide dating are required to confirm the basal age.
Ohio State researchers re-examined cores recovered in 1992 and 2015 from the same boreholes on the Guliya ice cap. Identical isotope stratigraphies across the two sets demonstrated that flow and melt had not erased the record, allowing the team to anchor the lower sections with cosmogenic nuclides that spike during the Laschamp geomagnetic excursion. Cross-validation against nearby cave speleothems confirmed the chronology.
The finding overturns earlier interpretations that placed the entire Guliya record within the Holocene. If ice survived the last glacial termination at these elevations, regional climate models that assume complete deglaciation of the northwestern Tibetan Plateau by 12,000 years ago require revision. The record now offers the only continuous mountain isotope archive spanning the last interglacial outside the poles.
Future coring at greater depth and replication at nearby ice caps will test whether the 128,000-year basal age is conservative. Expanded arrays of in-situ cosmogenic dates and noble-gas analyses could tighten the chronology and quantify past accumulation rates under warmer-than-present conditions.
Lonnie Thompson: Additional deep cores from Guliya will push basal ages past 150,000 years within four years of renewed drilling.
Sources (2)
- [1]Primary Source(https://www.science.org/doi/10.1126/sciadv.adu1254)
- [2]Supporting Source(https://www.sciencedaily.com/releases/2026/10/261028232713.htm)