Several dozen small impact craters, 10-70-m in size, have been discovered in southeastern Wyoming. A team of U.S. and German geoscientists found these ancient craters in exposed sedimentary layers from the Permian period (280 million years ago).

After discovering the first craters, the team initially suspected that they are a crater-strewn field, formed by the breakup of an asteroid that entered the atmosphere. However, with the discovery of more and more craters over a wide area, this interpretation was ruled out.

Many of the craters are clustered in groups and are aligned along rays. Furthermore, several craters are elliptical, allowing the reconstruction of the incoming paths of the impactors. The reconstructed trajectories have a radial pattern.

"The trajectories indicate a single source and show that the craters were formed by ejected blocks from a large primary crater," said project leader Thomas Kenkmann, professor of geology at the University of Freiburg, Germany. "Secondary craters around larger craters are well known from other planets and moons but have never been found on Earth,"

The team calculated the ballistic trajectories and used mathematical simulations to model the formation of the craters. All of the craters found so far are located 150-200 km from the presumed primary crater and were formed by blocks that were 4-8-m in size that struck the Earth at speeds of 700-1000 m/s.

The team estimate that the source crater is about 50-65 km in diameter and should be deeply buried under younger sediments in the northern Denver basin near the Wyoming-Nebraska border.

Research Report: "Secondary cratering on Earth: The Wyoming impact crater field"

Related Links
Geological Society of America
Asteroid and Comet Mission News, Science and Technology

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

DiCaprio and Lawrence big up science in doomsday comedy
Paris (AFP) Dec 17, 2021
For Hollywood A-listers Leonardo DiCaprio and Jennifer Lawrence, their new end-of-the-world comedy was a chance to send a little respect back to scientists. In "Don't Look Up", released on December 24 on Netflix, they play two astronomers who discover a comet will wipe out life on Earth within six months, but then try in vain to get politicians and the media to take the threat seriously. The parallels with the climate crisis were deliberate, and filming during the pandemic gave the film another ... read more