And they were a little shockedUnder the thick ice of the Hiawatha Glacier in northwestern Greenland, an impact crater 31 kilometers wide was buried. Previously, it was thought that it was no more than 100 thousand years old, but new data change this figure to a larger one.Discuss
In 2019, the team had a chance to determine the date of the collision directly. Returning to the rivers that flow from the base of the glacier and carry precipitation from beneath the ice, they found fist-sized rocks that had melted, presumably from the heat of impact.
In the study, Published today in the journal Science Advances, scientists report that in 28 of these impacted zircon crystals, the decay clocks indicate an age of 58 million years with an error of about 1 million years. Nearly 50 grains of sand collected from the same watershed, analyzed using the decay of radioactive potassium into argon, showed approximately the same age.
Source: Science.org