A promising target in the quest for a 1-million-year-old Antarctic ice core

Laura Kehrl on a hike near McMurdo Station while waiting for a flight to the Allan Hills area.

Ice cores offer a window into the history of Earth’s climate. Layers of ice reveal past temperatures, and gases trapped in bubbles reveal past atmospheric composition. The oldest continuous ice core so far comes from Dome C in East Antarctica and extends back 800,000 years.

But a tantalizing clue recently offered the possibility to go back even further. A collaborative study between the University of Washington and the University of Maine now pinpoints a location where an entire million years of undisturbed ice might be preserved intact.

“There’s a strong desire to push back the date of the oldest ice core record, to better understand what drives natural climate changes,” said Laura Kehrl, a UW doctoral student in Earth and space sciences and corresponding author of a recent paper in Geophysical Research Letters. “The Allan Hills has been an area of interest since the 1970s, when scientists started finding lunar and Martian meteorites that had struck Earth long ago. Now we’re discovering its potential for old ice.”