How the Arctic became salty

The Arctic Ocean hasn’t always been as salty as other oceans. In the Eocene, between 56 million and 34 million years ago, the water surrounding the North Pole — freshened by melt from sea ice and river runoff — was cut off from the Atlantic and Pacific oceans by land bridges. At some point, plate tectonic processes opened the North Atlantic, submerging the land bridges and allowing saltwater to pour into the Arctic, but the timing and details of these events are largely unknown. New research suggests a tipping point may have been reached as one particular land bridge submerged far enough below the ocean surface.

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Mary Caperton Morton

Mary Caperton Morton

Morton (https://theblondecoyote.com/) is a freelance science and travel writer based in Big Sky, Mont., and an EARTH roving correspondent.  

Monday, September 25, 2017 - 06:00