120,000 years deep

The North Greenland Ice Core Project has reached the end of the line at last.

After seven years and two miles of drilling, GRIP researchers ran out of ice and hit bedrock. [...]

When the ice core finally arrives in Copenhagen, scientists will need years to fully analyze it. They will measure levels of oxygen isotopes, study the gases trapped in microscopic air bubbles, and look for tiny bits of prehistoric dust literally frozen in time. With those scraps of evidence, they can determine what the temperature was at the North GRIP site for every single summer and winter going back at least 120,000 years. [...]

They knew the bottom was warm, heated by geothermal energy in the underlying rock, but they did not expect to be able to sample it. But it appears that the liquid spurted up and froze solid to the drill bit, which had passed through much cooler ice on the way down. The pocket of water could have been covered ever since the ice sheet was first formed, millions of years ago. "I couldn't believe my eyes," said Dr. Dorthe Dahl-Jensen, the project's chief scientist. "It could contain evidence of ancient life."

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