A team of scientists, including Tas van Ommen from the Hobart-based Australian Antarctic Division, say they have identified the most likely location of ice dating from 1.5 million years ago, almost double the oldest ice cores so far extracted, at 800,000 years.

In a paper published in the Climate of the Past journal, the researchers say they have narrowed down a region of the East Antarctic Ice Sheet as likely to contain the ice, possibly as much as 2.5 kilometres below the surface.

“One of the key things is that the ice will give us the carbon-dioxide levels [from that period]," Dr van Ommen said.