September 28, 2022

Massive Asteroid Impact Crater in Greenland Occurred a Few Million Years After Dinosaurs Went Extinct

Photo from fieldwork at the edge of the Greenland Ice Sheet in 2019. Credit: Pierre Beck
Swedish and danish scientists have actually dated the massive Hiawatha effect crater, a 31 km-wide meteorite crater buried under a kilometer of Greenlandic ice. The dating ends speculation that the meteorite affected after the appearance of human beings and opens a brand-new understanding of Earths advancement in the post-dinosaur age.
Since 2015, when scientists at the University of Copenhagens GLOBE Institute discovered the Hiawatha impact crater in northwestern Greenland, uncertainty about the craters age has actually been the topic of substantial speculation. Could the asteroid have knocked into Earth as just recently as 13,000 years ago, when human beings had long populated the world? Could its effect have catalyzed an almost 1,000-year period of worldwide cooling understood as the Younger Dryas?
Brand-new analyses performed on grains of sand and rocks from the Hiawatha impact crater by the Natural History Museum of Denmark and the GLOBE Institute at the University of Copenhagen, in addition to the Swedish Museum of Natural History in Stockholm, show that the response is no. The Hiawatha impact crater is far older. In truth, a brand-new research study published in the journal Science Advances today (March 9, 2022) reports its age to be 58 million years old.

Maps revealing the place of the Hiawatha effect crater in northwest Greenland (left) and the shape of Earths surface area beneath the ice, with the crater plainly noticeable (ideal). Credit: University of Copenhagen
” Dating the crater has actually been a particularly difficult nut to break, so its extremely satisfying that two labs in Denmark and Sweden, using different dating techniques showed up at the exact same conclusion. As such, Im convinced that weve identified the craters real age, which is much older than lots of people when believed,” states Michael Storey of the Natural History Museum of Denmark.
” Determining the new age of the crater shocked us all. In the future, it will assist us examine the impacts possible result on climate during an essential epoch of Earths history” states Dr. Gavin Kenny of the Swedish Museum of Natural History.
Crystals of the mineral zircon are small time-capsules that tape the age of numerous occasions in Earths history. Dating zircon crystals like this was among the two techniques used to compute the age of the Hiawatha effect crater. Credit: University of Copenhagen
As one of those who helped discover the Hiawatha effect crater in 2015, Professor Nicolaj Krog Larsen of the GLOBE Institute at the University of Copenhagen is delighted that the craters exact age is now verified.
” It is great to now know its age. Weve been striving to find a method to date the crater given that we discovered it seven years earlier. Since then, we have been on several expedition to the location to gather samples related to the Hiawatha effect,” states Professor Larsen
Age revealed by laser beams and grains of sand
When the Hiawatha asteroid rammed into Earth surface launching several million times more energy than an atomic bomb, no kilometer-thick ice sheet draped Northwest Greenland. At the time, the Arctic was covered with a temperate rainforest and wildlife abounded– and temperature levels of 20 degrees Celsius were the standard. Eight million years earlier, an even bigger asteroid struck contemporary Mexico, causing the extinction of Earths dinosaurs.
The NordSIMS laboratory at the Swedish Museum of Natural History, one of 2 laboratories where analyses were conducted to date the Hiawatha impact crater. Credit: University of Copenhagen
The asteroid smashed into Earth, leaving a thirty-one-kilometer-wide, one-kilometer-deep crater. The crater is huge enough to include the whole city of Washington D.C. Today, the crater lies beneath the Hiawatha Glacier in Northwest Greenland. Rivers streaming from the glacier supplied the researchers with sand and rocks that were superheated by the impact 58 million years ago.
The sand was analyzed at the Natural History Museum of Denmark by warming the grains with a laser up until they released argon gas, whereas the rock samples were evaluated at the Swedish Museum of Natural History using uranium-lead dating of the mineral zircon.
Picture from fieldwork at the edge of the Greenland Ice Sheet in 2019. Credit: Joe MacGregor
Clear evidence that the Hiawatha impact interfered with global environment is still doing not have. The craters dating allows the worldwide research team working on the crater to start checking different hypotheses to better comprehend what its impact was on both the global and local environment.
Facts:

Ever since 2015, when scientists at the University of Copenhagens GLOBE Institute discovered the Hiawatha effect crater in northwestern Greenland, uncertainty about the craters age has actually been the subject of significant speculation. New analyses carried out on grains of sand and rocks from the Hiawatha effect crater by the Natural History Museum of Denmark and the GLOBE Institute at the University of Copenhagen, as well as the Swedish Museum of Natural History in Stockholm, show that the answer is no. The Hiawatha effect crater is far older. Dating zircon crystals like this was one of the 2 techniques utilized to compute the age of the Hiawatha impact crater. The crater is big enough to contain the whole city of Washington D.C. Today, the crater lies underneath the Hiawatha Glacier in Northwest Greenland.

Reference: “A Late Paleocene age for Greenlands Hiawatha impact structure” by Gavin G. Kenny, William R. Hyde, Michael Storey, Adam A. Garde, Martin J. Whitehouse, Pierre Beck, Leif Johansson, Anne Sofie Søndergaard, Anders A. Bjørk, Joseph A. MacGregor, Shfaqat A. Khan, Jérémie Mouginot, Brandon C. Johnson, Elizabeth A. Silber, Daniel K. P. Wielandt, Kurt H. Kjær and Nicolaj K. Larsen, 9 March 2022, Science Advances.DOI: 10.1126/ sciadv.abm2434.

At 31 km throughout, the Hiawatha impact crater is larger than about 90% of the roughly 200 previously known effect craters in the world.
Although the Hiawatha effect crater is much smaller than the around 200 km-wide Chicxulub effect crater in contemporary Mexico, which led to the death of the dinosaurs, it would have ravaged the area and may even have had broader consequences for the environment and plant and animal life.
When the Hiawatha impact happened 58 million years ago the Earth had actually recuperated from the disastrous impacts of the Chicxulub effect eight million years previously and was going into a long-term warming pattern that was to last about 5 million years.

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