Ice core taken in Antarctica contains sample of atmosphere from five million years ago

Bob Yirka is a research scientist at Phys.org.

A team of researchers affiliated with multiple institutions in the U.S. pulled an ice core from a valley in the middle of the ocean. In their paper published in The Cryosphere, the researchers explain why they chose to drill in the Ong Valley and what they hope to learn.

The idea is to study the air bubbles that have been trapped in the ice, some of which have been there for millions of years. Most core samples have been pulled from eastern parts of Antarctica because the ice there has been deposited slowly.

The researchers chose to drill in the Ong Valley, which is located in the Transantarctic Mountains and is thought to separate eastern and westernAntarctica. The glaciers deposited ice in the valley. A layer of rock was created when the ice on top melted. It has been suggested that the ice could be as old as 5 million years ago. The ice in the Ong Valley is older than the ice in the east, which makes it easier to get a useful core.

The researchers were able to access the protected ice beneath the rock after drilling through the ice in the summers of 2017: The age of the ice is thought to be between 3 million and 5 million years old. Neon, aluminum, and beryllium can be used for age testing because they were created by Cosmic rays colliding with the rocks above. According to the researchers, the ice sheet below the rocks is made up of two sheets, one above the other, suggesting that there were two glaciers in the valley millions of years ago.

More information: Marie Bergelin et al, Cosmogenic nuclide dating of two stacked ice masses: Ong Valley, Antarctica, The Cryosphere (2022). DOI: 10.5194/tc-16-2793-2022 Journal information: The Cryosphere

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