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scpg02
Joined: 22 Jul 2007
Posts: 221
Location: Sacramento
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 Posted: Wed Oct 31, 2007 2:04 am Post subject: Meteor no longer prime suspect in great extinction |
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Contact: Carl Marziali
marziali@usc.edu
213-740-4751
University of Southern California
Meteor no longer prime suspect in great extinction
The Great Dying 250 million years ago happened slowly, say USC geologists
| Quote: | The greatest mass extinction in Earth’s history also may have been one of the slowest, according to a study that casts further doubt on the extinction-by-meteor theory.
Creeping environmental stress fueled by volcanic eruptions and global warming was the likely cause of the Great Dying 250 million years ago, said USC doctoral student Catherine Powers.
Writing in the November issue of the journal Geology, Powers and her adviser David Bottjer, professor of earth sciences at USC, describe a slow decline in the diversity of some common marine organisms.
The decline began millions of years before the disappearance of 90 percent of Earth’s species at the end of the Permian era, Powers shows in her study.
More damaging to the meteor theory, the study finds that organisms in the deep ocean started dying first, followed by those on ocean shelves and reefs, and finally those living near shore. |
http://www.eurekalert.org/pub_releases/2007-10/uosc-mnl102407.php
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John L
Joined: 03 Nov 2007
Posts: 21
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| Posted: Sat Nov 03, 2007 4:37 am Post subject: |
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| Quote: | “Something has to be coming from the deep ocean,” Powers said. “Something has to be coming up the water column and killing these organisms.”
That something probably was hydrogen sulfide, according to Powers, who cited studies from the University of Washington, Pennsylvania State University, the University of Arizona and the Bottjer laboratory at USC.
Those studies, combined with the new data from Powers and Bottjer, support a model that attributes the extinction to enormous volcanic eruptions that released carbon dioxide and methane, triggering rapid global warming. |
That reminds me of the explanation of extensive vulcanism being the most likely culprit. However, upon further examination, it was found that one of more Impactors would cause a ripple effect, thus opening up the earth directly on the other side of the planet.
Somehow, I suspect an Impactor again caused further outgassing from undersea venting. The Impactor theory just makes too much sense, and points to the most likely factor: celestial events. Further, the 26-31 million year repeat cycle is too strong to overlook.
What makes this entire thing so difficult is that when this solar system either crosses the galactic plane, or possible brown dwarf companion, passes near the Ort Cloud, it would shake up perhaps several million comets. But a large number may not always drop into the inner solar system, and again only a periodic random number would impact with the earth. Most times nothing may impact, while others, more than one would. It's purely random.
but one thing is certain, if it was celestial in nature, and I pretty much have no doubt to that, it is according to a precise timetable.
One other thing. I really don't understand why the word "Meteor" or "Astroid" is used all the time. Those things really rely on random events. The correct word is "Comet", and they can wreck more havoc, because they are larger, and come in with over twice the speed. They simply would not have the time to calve in the atmosphere unless they came in on a sharp angle. |
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Andre
Joined: 21 Jul 2007
Posts: 298
Location: Germany - The Nederlands
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| Posted: Sat Nov 03, 2007 2:40 pm Post subject: |
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indeed the dating of the Siberian traps flood basalt volcanism, the largest on record, closely agrees with this P-T extinction event.
However the Mexical Chicxulub impact and the Deccan traps flood basalt volcanism in India seem to agree nicely with the Dinosaur extinction but the dating is off, I seem to remember
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Mk
Joined: 22 Jul 2007
Posts: 18
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| Posted: Wed Nov 07, 2007 7:37 pm Post subject: |
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| Quote: | | One other thing. I really don't understand why the word "Meteor" or "Astroid" is used all the time. Those things really rely on random events. The correct word is "Comet", and they can wreck more havoc, because they are larger, and come in with over twice the speed. |
Comets have tails, asteroids don't, meteors are comets or asteroids that have hit the Earth. Also, I don't believe there are any naming specifications that have to do with size, with comets or asteroids being larger or smaller than each other. They're just all rocks, some with ice on them. Comets do seem to tend to be faster and asteroids.
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