Thursday, September 17, 2015

Double Impact Crater Found in Sweden From Floian/Dapingian Ordovician, Possibly Linked to Proposed Ordovician Meteor Event

Double rainbows have nothing on Earth’s newest dynamic duo: the double crater.

Researchers from the University of Gothenburg have uncovered two impact craters in Jämtland, Sweden, which they believe to have occurred simultaneously around 460 million years ago. Double meteor impacts are rare events, and the discovery in Sweden is the first proven instance of its kind.

“Information from drilling operations demonstrates that identical sequences are present in the two craters, and the sediment above the impact sequences is of the same age. In other words, these are simultaneous impacts,” said Erik Sturkell, professor of geophysics at the University of Gothenburg and a member of the team that found the double crater, in a university statement.

Although these two meteorites struck at the same time, that does not mean they are physically alike, however. One crater measures a massive 4.7 miles in diameter, while the other, which was located nearly ten miles away, was a much a smaller 2,300 feet across.

As for how it happened, it all started in the stars.

“Around 470 million years ago, two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland,” said Sturkell.


There are several impacts in North America and another in Estonia that roughly line up.  This hypothesized event is termed the "Ordovician Meteor Event."  They are all supposedly within a million years of each other and I wonder though whether or not they line up given the paleogeography. 

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