Ancient permafrost permafrost

2008/11/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia
• Klima

Volcanic ash from the northwest of Canada has been dated and, incidentally, the oldest known piece of ice in North America has been identified. Volcanic ash is found on a permafrost layer and a researcher at Alberta University of Canada estimates that they are between 680,000 and 800,000 years old. This means that ice under the ashes must be at least that age.

This discovery has surprised scientists, who until now considered that the heat that occurred about 120,000 years ago melted all areas of permafrost in the area. However, for the ashes to be on the permafrost, the ice had to inevitably maintain that heat. Therefore, in that specific area, at least, it did not completely melt.