Volcanic eruptions, not astroids caused mass extinction on Earth

A New scentific study released this week says life on earth 450 million years ago, was not killed off by an asteroid as scientists have said for years. The new study says the cause was globle warming.

A new study conducted by researchers at the University of Washington suggests that atmospheric warming because of greenhouse gases triggered by erupting volcanoes caused the biggest extinction on Earth.

Researchers led by paleontologist Peter Ward said they have found no evidence for an impact at the time of "the Great Dying" 250 million years ago. It occurred at the boundary between the Permian and Triassic periods at a time when all land was concentrated in a supercontinent called Pangea.

"The marine extinction and the land extinction appear to be simultaneous, based on the geochemical evidence we found. Animals and plants both on land and in the sea were dying at the same time, and apparently from the same causes - too much heat and too little oxygen," ward said.

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Biggest mass extinction tied to global warming
New evidence shows the culprit was volcanic gases

Scientists call it the Great Dying, a 250-million-year-old catastrophe that wiped out 90 percent of ocean species and 70 percent of land species in the biggest mass extinction in Earth's geologic history.

The cause of this cataclysm is a matter of great dispute among paleontologists, but research released Thursday offers new evidence that global warming caused by massive and prolonged volcanic activity may have been the chief culprit.

Huge amounts of carbon dioxide were released into the air from open volcanic fissures known to geologists as the "Siberian Traps," researchers said, triggering a greenhouse effect that warmed the Earth and depleted oxygen from the atmosphere, causing environmental deterioration and finally collapse.

I am wiling to bet the scientific community will no doubt be fighting over this for years; what do you think?

It would be difficult to prove that a meteorite didn't set off a large volcanic erruption to begin with.

Most studies are showing the increased CO2 levels during a mass extinction. There doesn't seem to be any doubt that this does occur.

Our atmosphere in its current state seems dependent on life. If one ecosystem on one side of the planet starts dying off, it raises the CO2 levels for the rest of the planet, which again leads to further ecosystems dying and further CO2 buildup.

This all suggests to me that it wouldn't take much to set off a chain of events which leads to a "mass dying" of land animals and plants. Perhaps land based life is only able to persist through ocean creatures. Some of which will evolve back onto land.

already covered sorry
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Originally posted by klain
already covered sorry

www.abovetopsecret.com...

This is a different catastrophic extinction...much older than the one you're referencing.


There's been a lot of research into the end-Permian extinctions in recent years, and the tide seems to be turning towards the flood basalt theory -- even before this study.

Flood basalt flows are the most destructive (and rare - 8 have occurred in the last 200 million years) of all volcanic activity. Rather than a massive eruption as with, say Mount St. Helens, or a catastrophic explosion as with the Toba caldera 75,000 years ago, basalt flows are a massive and long-term "oozing" (for lack of a better term) of lava from fissures in the Earth's crust.

Basically there's a huge pool of magma underneath parts of Siberia (aka the Siberian Traps). When pressure builds up enough, the earth ruptures in multiple locations above the magma pool and the lava just starts pouring out and spilling all over the place. When this baby blew 450 million years ago, the lava covered an area about the size of the whole of Europe!!!
The destructive part comes into play when one takes into account just how long a basalt flood eruption lasts.
Rather than a relatively short eruptive process as with "normal" volcanos, basalt flood pyroclastics last for a million years or so. That's a million years of lava constantly pouring out of the earth.

With the Siberian Traps, theory is that the gas and ash emitted by the eruption caused a massive and catastrophic global temperature drop. If you'll remember the Indonesian eruption in the 19th century, that caused a drastic change in world climate. The summer following the eruption has been called "the year without a summer" because of the climate effects of ash and gases in the atmosphere.
That eruption was but a hiccup compared to the Siberian Traps.


[edit on 23-1-2005 by Banshee]

Originally posted by klain
already covered sorry

www.abovetopsecret.com...

You are correct. Although a better titile than "we're gonna die" could have been used.

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