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Massive Volcanism May Have Caused Biggest Extinction Ever:

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posted on Dec, 15 2010 @ 07:44 AM
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SAN FRANCISCO — The greatest extinction in the history of life may have been caused, in part, by ozone-depleting gases spewed in a massive volcanic eruption, a new study suggests. Geologists have found surprisingly high amounts of the elements fluorine and chlorine in Siberian lavas dating back 250 million years — when about 90 percent of marine species and 70 percent of terrestrial species went extinct. Benjamin Black, a graduate student at MIT, and his colleagues described their theory Dec. 13 in a poster presentation at a meeting of the American Geophysical Union

Researchers have long struggled to explain the “Great Dying” that occurred at the end of the Permian period. Some think that the extinction was a long, drawn-out affair caused by multiple factors — perhaps gradual changes in oceanic or atmospheric chemistry (SN: 5/28/05, p. 339). Others have blamed a single catastrophic event such as a belch of methane from the seafloor or an asteroid impact (SN: 2/24/01, p. 116) like the one thought to have wiped out the dinosaurs and other species 65 million years ago.

Volcanoes might be one of those calamities. In Siberia, around 250 million years ago, a series of massive volcanic eruptions spewed out lava over more than 2 million square kilometers [800,000 square miles]. Some scientists have blamed these eruptions, known as the Siberian Traps, for climatic changes that contributed to the extinction. Black and his MIT adviser, Lindy Elkins-Tanton, have been traveling to Russia for the past few summers to test such theories in the Siberian Traps.

The rocks contain tiny blobs of once-molten material, preserved like chemical time capsules from the earliest days of the eruption. Measuring the amounts of sulfur, chlorine and fluorine in those blobs, Black found surprisingly high levels of those elements — up to 0.75 percent chlorine and 1.95 percent fluorine, by weight, in one sample. That’s significantly more than the amounts found in similar deposits like the Deccan Traps in India and the Columbia River flood basalts in Washington and Oregon.

Source: www.wired.com...

To me, this makes a lot of sense and the most sense. Other than some massive object hitting the earth and causing worldwide blackout/damage. the only other way is from within. meaning Mother Nature.

Especially in that region they went to. 1000's of miles of nothing but trees. All the same height (most). Like it all got wiped out at the same time. I think the only thing possible is volcanos-especially if most went off at the same time. Watch out.

Sure hope the Earth is done with big flare ups like that. IF something did happen, I just don't think the WHOLE world would be wiped out. Effected-possibly, wiped out No.




posted on Dec, 15 2010 @ 01:01 PM
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reply to post by anon72
 

The cause of the permian extintion has been abtted around for a number of years.
The mechanisms for the formation of large igneous provinces, ie the deccan & siberian traps, is the subject of much debate.
The fact that mantle plumes break through the surface and deposit vast amounts of magma on the surface is not in question, but what is the mechanism that causes them is the question.

In the case of the permian event we know that there was a large influx of CO2 into the atmosphere and world ocean at the time, as well as the formation of the siberian traps. But was it the siberian traps that caused the outflow of CO2 or was symptamatic of another seeemingly unrelated event?

In a paper bya USGS researcher, Antipodal hotspots and bipolar catastrophes: Were oceanic large-body impacts the cause? , the argument is made that magma plumes resulting in large igneous provinces are likely caused by large body impacts upon deep oceanic crust.



A mechanism of formation is considered in which minor hotspot volcanism is induced at, and flood basalt volcanism is triggered by seismic energy focused antipodal to, oceanic large-body impact sites



Essentially what they are saying is that, If a large enough body impacts on deep ocean crust, most of the energy is absorbed by the earth and refocused around the core and will erupt out the opposite(anti-podal) side of the earth, causing a large basalt flood.
This idea is backed up by the fact that 50% of the know continental hot spots have antipodal oceanic hot spot paired with it.

Basicaly when a large asteriod or comet hits a continent, most of the energy is reflected back into space or the atmosphere, by the much thicker and more rigid continental crust, via the ejecta plume.
But when such an impact occurs in an ocean basin almost all of the energy is absorbed by the earthe to be refocused to the opposite side, causing a large mantle plume to break thorugh.

This idea has been supported by continental hotspots, and their known oceanic pairs.
When continental drift is taken into account it is highley likely that the deccan traps in india, are the antipodal hot spot to the chixilub( dinosuar killer) impact event.

One paper i read several years ago put the likely impact, opposite of the single continent that exsisted at the time, in the single worlds ocean.

And when you go back that far there will be no crater to find, since no oceanic crust is older than 125 million years.



posted on Dec, 15 2010 @ 01:04 PM
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And at that time what we know call siberia was likely part of the vast desert that covered most of pangea.


The evidence is very good for impacts being the cause of vast flood basalts.



posted on Feb, 3 2011 @ 12:20 PM
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New evidence for this theory, in February issue of the journal NATURE, excerpted here:

www.world-science.net...

Buchanan Lake, CANADA: Layers of coal ash found in a layer of rock associated with the time of the extinction.



Grasby studied the formations with University of Calgary colleagues Benoit Beauchamp and Hamed Sanei. “We saw layers with abundant organic matter and Hamed immediately determined that they were layers of coal ash, ex­actly like that produced by modern coal burning power plants,” said Beauchamp. “Our discovery provides the first direct confirmation for coal ash during this extinction, as it may not have been recognized before,” added Sanei.



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