A team of scientists from several U.S. institutions, including the University of Minnesota, discovered six million year old ice in Antarctica - the oldest dated ice on the planet.
The collaborative NSF COLDEX team recovered the ice in the Allan Hills region of Antarctica during the 2019-20 and 2022-23 austral summer science seasons, supported by the United States Antarctic Program. Ice cores drilled in Antarctica and the air bubbles they contain provide valuable insights into Earth's climate history. The team's findings, recently published in PNAS, could help scientists better understand the planet's climate during a time of warmer temperatures and higher sea levels.
The ice was dated using Argon-40 isotopes, which are produced by radioactive decay of Potassium-40 in Earth's crust and accumulate in the atmosphere over time. These isotopes were initially discovered and studied in the 1930s and 40s at the University of Minnesota by physicist and professor Al Nier in Tate Hall. Precise work on atmospheric Argon isotopes by Nier were fundamental to using this and other isotopes as geologic clocks.
The NSF COLDEX researchers found:
- The six-million-year-old ice preserved in Antarctica more than doubled the next oldest ice samples found at the same site. It is nearly six times older than the current oldest continuous ice core record which extends from today back 800,000 years.
- Isotopic measurements that estimate temperature show progressive cooling at the Antarctic site through the Pliocene - the geologic time period between 5.3 and 2.6 million years ago - with even warmer temperature signatures before that.
- This old ice archive allows for study of these times when Earth was warmer and sea level was higher - independent of the human-caused warming and sea level rise observed today.
"Future research on these ice cores has the potential to provide unique insight into many fundamental questions in paleoclimate science. These include the history and stability of the Antarctic ice sheet and its relationship to atmospheric greenhouse gases and average ocean temperature, and could have direct implications for future projections of ice sheet sensitivity, sea-level rise, and global temperature," said co-author Peter Neff, an assistant professor in the College of Food, Agricultural and Natural Resource Sciences at the University of Minnesota and co-director for knowledge transfer for NSF COLDEX. Neff leads the University of Minnesota Neff Ice and Climate Exploration lab, which has recently collected new ice cores in Canada and Antarctica.
In addition to Neff, University of Minnesota collaborators on NSF COLDEX research include NSF COLDEX co-director for knowledge transfer Heidi Roop, Extension specialist, associate professor and director of the University of Minnesota Climate Adaptation Partnership. Land and Atmospheric Science graduate student Bridget Hall traveled to the South Pole in 2024 as part of an NSF COLDEX geophysical survey team. Martin Froger Silva, University of Minnesota Climate Adaptation Partnership and NSF COLDEX digital communications coordinator, is currently in Antarctica with an NSF COLDEX team collecting additional ice cores at the Allan Hills blue ice area and documenting the experience via Instagram.
Future research includes a proposed second phase of NSF COLDEX research in Antarctica from 2026 through 2031.
NSF COLDEX is supported by the NSF Office of Polar Programs; the Science and Technology Center Program at the NSF Office of Integrative Activities; and Oregon State University. Fieldwork in Antarctica is supported by the U.S. Antarctic Program and funded by NSF. Ice drilling support is provided by the NSF U.S. Ice Drilling Program, and ice sample curation by the NSF Ice Core Facility in Denver, Colorado.
About the College of Food, Agricultural and Natural Resource Sciences
The University of Minnesota's College of Food, Agricultural and Natural Resource Sciences strives to inspire minds, nourish people, and sustainably enhance the natural environment. CFANS has a legacy of innovation, bringing discoveries to life through science and educating the next generation of leaders. Every day, students, faculty, and researchers use science to address the grand challenges of the world today and in the future. CFANS offers an unparalleled expanse of experiential learning opportunities for students and the community, with 12 academic departments, 10 research and outreach centers across the state, the Minnesota Landscape Arboretum, the Bell Museum, and dozens of interdisciplinary centers. Learn more at cfans.umn.edu.
