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An international team of geoscientists from the United States, Canada and Europe has discovered a large impact crater beneath the Hiawatha Glacier in remote northwest Greenland. A paper on the discovery was published in the journal Science Advances. The Hiawatha impact crater is approximately 19.2 miles (31 km) wide and lies under an ice sheet that is 0.6 miles (1 km) thick.The scientists believe this crater was formed by a 0.6-mile wide iron asteroid that slammed into the Earth at the end of the Pleistocene epoch, perhaps as recently as 12,000 years ago. ..." “Researchers were looking at the map...

On a bright July day 2 years ago, Kurt Kjær was in a helicopter flying over northwest Greenland—an expanse of ice, sheer white and sparkling. Soon, his target came into view: Hiawatha Glacier, a slow-moving sheet of ice more than a kilometer thick. It advances on the Arctic Ocean not in a straight wall, but in a conspicuous semicircle, as though spilling out of a basin. Kjær, a geologist at the Natural History Museum of Denmark in Copenhagen, suspected the glacier was hiding an explosive secret. The helicopter landed near the surging river that drains the glacier, sweeping out rocks...

Canadian geologists say they can shed light on how a vast lake, trapped under the ice sheet that once smothered much of North America, drained into the sea, an event that cooled Earth's climate for hundreds of years. During the last ice age, the Laurentide Ice Sheet once covered most of Canada and parts of the northern United States with a frozen crust that in some places was three kilometres (two miles) thick. As the temperature gradually rose some 10,000 years ago, the ice receded, gouging out the hollows that would be called the Great Lakes. Beneath the ice's thinning...