Earth's Volcanism Linked To Meteorite Impacts

New Scientist ^ | 12-13-2002 | Kate Ravilious

[blam]

I nominate the 1628BC explosion of Santorini (Exodus) as a candidate for a meteorite impact.

[blam]

Ping.

[onedoug]

'Could say something about the Hawaiian hot spot, which does not apprear tectonically driven. Interesting....

[freedumb2003]

You know, Al Gore invented meteorites. ;)

[dirtboy]

Dallas Abbott from Columbia University and her colleague Ann Isley from the State University of New York studied the timing of these 38 impacts and found that they correlate strongly with eruptions of "mantle-plume" volcanoes during the same period.

Considering, for example, that Hawaii and Iceland are hot-spot (or mantle-plume) volcanic zones, they erupt almost continually, so of course you'll be able to get a correlation with such features. And the impact at the end of the Cretateous down in Yucatan did not create a plume, and that was a biggie. Dittoes for the impact at the southern end of the Chesapeake - I don't see a Mt. Norfolk erupting down there.

It would be more impressive if the researchers were able to correlate major impacts with outbreaks of flood basalts. Now THOSE are truly nasty...

[dirtboy]

For example, the 10 kilometre-wide asteroid that hit Chicxulub in Mexico 65 million years ago is widely blamed for wiping out the dinosaurs. But it could have been a piece from a much bigger rock that hit India, triggering the surge of volcanic activity known as the Deccan Traps.

The Yellowstone hot spot created the Columbia flood basalts. There does not have to be correlation with an impact to get these events. Plus, 65 million years ago, India was very close to the Reunion hot spot, an extremely active one. They need more evidence and less inference.

[ALASKA]

You know, Al Gore invented meteorites. ;)

This new theory perplexes me; why would Al Gore invent meteorites which could possibly do so much damage to one of his other creations, Earth?

[Mike Darancette]

'Could say something about the Hawaiian hot spot, which does not apprear tectonically driven. Interesting....

Backtrack the Hawaiian hotspot on the earth's crust to where the impact might have been. Remember hotspots remain stationary in reference to the earth's crust while the plates move over them.

[Mike Darancette]

hotspots remain stationary in reference to the earth's crust

crust s/b core my bad!!!

[Mike Darancette]

And the impact at the end of the Cretateous down in Yucatan did not create a plume,...

EXTRATERRESTRIAL INFLUENCES ON MANTLE PLUME ACTIVITY

Earth and Planetary Science Letters
Volume 205, Issues 1-2, 30 December 2002, Pages 53-62
by Dallas H. Abbott and Ann E. Isley

Abstract

We use time series analysis to compare the impact histories of the Earth and Moon with the record of mantle plume activity. We use events with errors in their ages of 150 Ma. The terrestrial and lunar impact records, when smoothed at a 45-Ma interval, correlate at a 97% confidence level. This high confidence level suggests that we have an adequate sampling of most of the major impact events on the Earth. We then test the idea that existing mantle plumes may be strengthened by impacts. When smoothed at a 45-Ma interval, strong plumes correlate with the terrestrial impact record at better than a 99% confidence level. No time lag is discernible between the data sets, which is expected given their present error level. When the time series are smoothed at a 30-Ma interval, there are 10 major peaks in impact activity. Nine out of ten of these peaks have a counterpart in either or both of the strong mantle plume or the mantle plume time series. As a result, the strong mantle plume and the impact time series correlate at the 97% confidence level. The mantle plume and the impact time series correlate at the 90% confidence level. Finally, the Deccan plume showed greatly increased activity immediately after the Chixculub impact. The results of our analysis suggest that large meteorite and cometary impacts may well increase the amount of volcanism from already active mantle plumes.

Also, I thought that Iceland was an area where the sea floor was spreading.

[blam]

"And the impact at the end of the Cretateous down in Yucatan did not create a plume,..."

I read that the Chicxulub meteorite came in at a 35 degree angle, may be that's why it didn't 'punch' through.

[Mike Darancette]

I read that the Chicxulub meteorite came in at a 35 degree angle, may be that's why it didn't 'punch' through.

Exactly so, even a smaller object hitting at higher angle would be more likely to punch through. Also an object hitting mid-ocean (where the crust is thin) would be more apt to create a plume.

[onedoug]

Re the Emperor Seamount chain, which abruptly trends more westerly about midway toward the Aleutians, where its earlier remnants are finally subducted, to be reassimilated back into the mantle.

What a world, eh?

[VadeRetro]

I nominate the 1628BC explosion of Santorini (Exodus) as a candidate for a meteorite impact.

Doesn't fit the profile. From Pellegrino's Unearthing Atlantis, it had a long history as a volcanic hotspot before and since the Iron Age biggie that devastated Minoan Crete 70 miles over the water. The Thera (where did you get Exodus?) excavations seem to show pipes for geothermal hot and cold running water.

[VadeRetro]

Not to mention that a big earthquake apparently devastated the city on Thera, leading to its near-total abandonment well before the explosion.

[John H K]

One of the worst candidates you could find. For one, it's not big enough (the article is talking about truly gigantic flood-basalt type eruptions....comparitavely, Santorini was small and localized.)

Also, Santorini is on a plate boundary, and its existence can be easily ascribed to normal tectonic volcanism.

[null and void]

I am crazy or can yall visualize this too?

You're crazy, but I don't see what that has to do with this ;^)

The Deccan traps were not at the antipodes from the Chicxulub impact site. The shock waves from Chicxulub would not meet at that point. A paired asteroid impact could explain both features.

A more interesting question (and possible proof of the theory) is where is the contra coup scars from the Deccan and or Siberian traps? If either one was a scar from a BIG impact, there should be "disturbed" features 180° from it. Anyone know what was opposite India 65 mya? Or Siberia 230 mya? Does either exhibit shattered rock, or have they been subducted in the meanwhile?

The other obvious question is where are the other impact debris, surely all the splatter couldn't have reached escape velocity, could it?

Also, I highly recommended this book: T.rex and the crater of doom by Walter Alvarez, Princton University Press, ISBN 0-691-01630-5. Not only is it a very well told tale of the discovery of the Chicxulub impact site, it is a superb geology text. It packs a tremendous geology education in an accessible, easy to digest and understand form.

[RightWhale]

Two things. Would punching a hole in the crust actually produce a volcano? It's not as if the interior of the earth is just waiting for this in order to break through.

The other thing is the Martian volcanos, which correlate with a basin on the other side of the planet and look like a large asteroid plowed right through the planet and punched almost through in the earea of the volcanos, which are grouped in a relatively small area.

[blam]

"it had a long history as a volcanic hotspot before and since the Iron Age biggie that devastated Minoan Crete 70 miles over the water. "

Yup, that's my argument against an impact also. It's in an already previously active area.