Maine Crater Related to Dino-Killer Asteroid?

April 3, 2003 — The evidence is still skimpy, but there is a chance that the dino killer asteroid was not alone when it walloped the Earth 65 million years ago.

A possible second crater, at least as big or bigger than the famous Chicxulub crater off Mexico's Yucatan peninsula, may have been created by a second hit moments after Chicxulub and off the coast of Maine.

"It probably is a crater, but we really don't have age data," said marine geologist Dallas Abbott Lamont-Doherty Earth Observatory at Columbia University.

What makes Abbott suspect a crater is a large and unexplained difference in the magnetism of the crust in the Gulf of Maine. Then there is an arrangement of ridges on land that channel rivers and streams in Maine and Massachusetts along arcs that might be ridges of the western part of an eroded crater, said Dominic Manzer a NASA spacecraft engineer.

Abbott and Manzer presented their very preliminary work on what they are calling the Small Point crater late last week at a regional meeting of the Geological Society of America in Halifax, Nova Scotia.

Other asteroid and crater specialists are not so optimistic that the Gulf of Maine will yield a crater that corresponds with the end of the dinosaurs — the Cretaceous-Triassic (K-T) boundary 65 million years ago.

"There is no evidence of an impact event," said David Kring of the Lunar and Planetary Laboratory at the University of Arizona. What's more, if there were a second impact, said Kring, there would be a second blanket of debris at the K-T Boundary, which so far is not there.

Abbott agrees that the evidence is slim at this point. In fact, glaciers of past ice ages probably scoured away all the real rock evidence on the surface long ago, she said. That's why she hasn't tried to publish any official papers on the matter.

Instead, she intends to start looking further south, in the Martha's Vineyard area, for any impact-related rocks of the right age that might have been dropped there after the glaciers retreated.

If there was a double impact, said Manzer, it could have been that the asteroid or comet broke up before hitting Earth, leaving a rapid-fire line of craters, as has been seen on other planetary bodies in the solar system.

Shoemacher-Levy Jupiter impact pattern...(?)

Shoemacher-Levy was a comet, the mechanism for a comet breaking up in space is much better known than that of an asteroid. There are many examples of comets fragmenting.

Multiple impacts may tend to point to a comet as being the agent of the death of the Dinosaurs.

Aren't they thinking that we got hit repeatedly over the course of about 10 years?

Shoemaker (http://www.phys.uit.no/fys120/bibliotek/articles/Hitting_Home.pdf) says that there are two very-close-together layers of iridium at the K-T boundary far enough apart for plants to have started growing in-between.

He mentions Chicxulub, Manson in Iowa and Kara in Russia as three big impacts.

This could explain why every few months we see an article that says, "THIS is the one that wiped out the dinosaurs!".

Truly an amazing compilation Civ!

Ran across a minor problem: None of the links would open. Took me a couple of minutes to figure out the malfunction and it will be immediately apparent to you if you go back and take a look at the link addresses. There's an extra "/focus" in the addy that needs to go away. Now, being an industrious sort, and coincidentlally figuring out a quick and dirty, not to mention painless fix, once more with feeling:

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