Scientists have recovered ice cores from the Guliya Plateau in northwestern Tibet containing a frozen record stretching back more than 128,000 years, according to findings published in Science Advances. The discovery extends the known glacial record in the region by over 100,000 years, providing a rare window into how mountain glaciers survived major shifts in Earth’s climate since the last ice age.
Ice Core Samples Reveal 128,000 Years of Tibetan Climate History
Researchers examined ice cores collected from the Guliya ice cap during expeditions in 1992 and 2015. Despite a 23-year gap between the drilling operations, laboratory analysis showed strikingly similar patterns of oxygen isotopes across both sets of samples. Scientists use these isotope ratios to reconstruct past environmental conditions and verify that ice layers preserve a reliable historical record.
“Reproducibility of the records within a given ice cap is extremely important,” explained Lonnie Thompson, who serves as lead author of the study, earth sciences professor, and senior research scientist associated with The Ohio State University’s Byrd Polar Research Center. “If you get an identical record a quarter of a century later, it can tell you a lot about the behavior of the ice over time.”
Advanced Dating Techniques Track the Leschamp Geomagnetic Excursion
Establishing an accurate timeline for ice frozen for tens of thousands of years requires specialized methods. The international research team analyzed radioactive isotopes of beryllium and chlorine, which decay at predictable rates. These elements helped identify chemical signatures left by the Leschamp Geomagnetic Excursion, a major disturbance in Earth’s magnetic field that occurred more than 41,000 years ago.
By comparing these isotope markers with oxygen records from nearby Tibetan cave deposits, the team confirmed that the ice dates back beyond 128,000 years. “It’s a really critical finding, because outside of the polar regions, this is the only ice core we have from the mountaintops that go back that far,” Thompson said.
Survival of Glaciers Through the Holocene Epoch
Prior interpretations suggested the Guliya ice cap reached back only to the middle of the Holocene, the geological epoch beginning nearly 12,000 years ago after the last ice age. The new timeline proves that portions of the ice cap survived the transition to the Holocene, settling questions about the persistence of major mountain ice sheets.
“If we only had Holocene-era ice in Tibet, that would mean that the big ice sheets from the last ice age didn’t persist through the early Holocene,” Thompson noted. “But evidence shows that it did.”
Researchers Study Guliya Ice Cores to Clarify Climate Cycles
Researchers plan to study additional samples from the Guliya ice cores to investigate how other environmental indicators align with the revised timeline. The work aims to clarify natural climate cycles, including when major glaciation periods began and how ice sheets retreated over millennia.
“When did ice start forming on the planet and what did those natural processes of loss look like?” Thompson said. “We need to know those things, and the only way you can really demonstrate it is with accurate time scales on these records.”
Common Questions About the Guliya Ice Core Discovery
When were the Guliya ice core samples collected?
Researchers gathered the samples during two separate expeditions to the Guliya Plateau in northwestern Tibet, drilling the first set in 1992 and returning to collect additional ice cores in 2015.
Why are oxygen isotopes important in ice core research?
Scientists analyze oxygen isotopes to reconstruct past environmental conditions. Matching isotope patterns across samples drilled decades apart proves that the ice preserves a reliable and reproducible record of climate history.
How did researchers determine the ice was over 128,000 years old?
The team used advanced dating methods involving radioactive isotopes of beryllium and chlorine. These elements identified chemical signatures from the Leschamp Geomagnetic Excursion, a magnetic field disturbance that occurred more than 41,000 years ago.
Who funded and contributed to the study?
The research received support from the U.S. National Science Foundation. The investigation’s co-authors featured Mary Davis alongside Ellen Mosley-Thompson from Ohio State, Juerg Beer representing the Swiss Federal Institute of Aquatic Science and Technology, Christof Vockenhuber together with Marcus Christl from ETH Zurich, Tandong Yao affiliated with the Chinese Academy of Sciences, and Ninglian Wang along with Ling Fang of Northwest University.
Worth a look
- Bridget Maasland shares details about mother Elly cancer recovery
- JAMSTEC Cultivates Heimdallarchaeia to Reveal Eukaryote Origins
- Brewers vs. History: 25 of 25 Teams Up 3-0 Won the World Series (daybreakwire.com)
- Why Alejandro G. Iñárritu’s “Digger” Is a Crucial Climate Film Starring Tom Cruise (archyde.com)