Immense Prehistoric Ice Sheets Discovered in Arctic: Climate History Rewritten

Massive ice sheets spanned the world during the ice ages during the Pleistocene. Now, scientists have discovered that one of these ice sheets was located on a seamount off the north-eastern coast of Russia. The findings reveal for the first time that within the past 800,000 years that ice sheets also formed in the Arctic Ocean. The research could mean that the climate history for this part of the Artic needs to be rewritten.

The researchers journeyed to the Arctic on an expedition in 2008. However, it's only in 2012 that the scientists were able to gather extensive proof of the existence of a past ice sheet. They analyzed the bathymetric and seismic data from the first voyage, which allowed them to survey the ocean floor with sonar during their second expedition.

So what did they find? They discovered a seamount called the Arlis Plateau. Deep, parallel-running furrows can be seen on the upper plateau and the sides over an area of about 2500 square kilometers at an ocean depth of 1200 meters.

"We knew of such scour marks from places like the Antarctic and Greenland," said Frank Niessen, one of the researchers, in a news release. "They arise when large ice sheets become grounded on the ocean floor and then scrape over the ground like a plane with dozens of blades as they flow. The remarkable feature of our new map is that it indicates very accurately right off that there were four or more generations of ice masses, which in the past 800,000 years moved from the East Siberian Sea in a northeasterly direction far into the deep Arctic Ocean."

The new findings actually overturn the traditional view of the history of Arctic glaciations. Previously, many researchers believed that mega-glaciations only took place on the continents. They assumed that the continental shelf region of Northeastern Siberia became exposed in these ice ages and turned into a vast polar desert with not enough snow to create a thick ice shield over the years. Yet it seems now that the opposite was true.

"With the exception of the last ice age 21,000 years ago, ice sheets formed repeatedly in the shallow areas of the Arctic Ocean," said Niessen. "These sheets were at least 1200 meters thick and presumably covered an area as large as Scandinavia."

Currently, the researchers plan to continue to study the area to find out a bit more about the history of the location. The findings could inform future climate models for the Arctic region and could potentially predict changes to the area as a result of climate change.

The findings are published in the journal Nature Geoscience.