Gas-belching volcanoes may have killed dinosaurs

Reuters on Yahoo ^ | 3/20/08 | Ben Hirschler

[NormsRevenge]

LONDON (Reuters) - Gas-belching volcanoes may be to blame for a series of mass extinctions over the last 545 million years, including that of the dinosaurs, new evidence suggested on Thursday.

A series of eruptions that formed the Deccan Traps in what is now India pumped huge amounts of sulfur into the atmosphere 65 million years ago, with likely devastating repercussions for the Earth's climate, scientists said.

Gigantic eruptions, forming so-called "flood basalts," are one of two leading explanations for a series of mass extinctions that have killed off species periodically throughout history.

The other theory involves asteroid impacts -- generally considered the prime suspect in the case of the extinction of dinosaurs 65 million years ago.

There have been doubts about the killing power of volcanoes because, until now, researchers have struggled to measure just how much toxic gas would have been released.

But after finding rare inclusions of glass in the Deccan rock, a British-based team has found vital preserved information about its original gas content.

Writing in the journal Science, they concluded that the massive of amounts of both sulfur and chlorine released would probably have had a "severe" environmental impact.

"It certainly bolsters the case, though it doesn't prove it," Stephen Self, formerly of Britain's Open University and now senior volcanologist with the U.S. Nuclear Regulatory Commission, said in an interview.

"There have been several major mass extinctions and most of those have, uncannily, occurred while one of these huge flood basalt provinces was being formed."

The volcanoes may have spewed 10 times as much sulfur into the atmosphere every year as humans have done recently by burning coal in power stations and through other industrial activities.

The result would have been widespread acid rain and aerosols of sulfuric acid in atmosphere, cooling the surface of the Earth and upsetting normal patterns of circulation.

[NormsRevenge]

lol.. The turkey will be pleased to hear that..

[SunkenCiv]

Uh-kay. ;’)

[SunkenCiv]

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Comet/Asteroid Impacts and Human Society ed by Peter T. Bobrowsky and Hans Rickman intro (PDF) due to links here

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[wolfcreek]

I believe 1/2 or more of the Yucatan crater was in water. (don’t know the depth at that time)

I’m sure what ever happened then was *worse *case* or close to it.

Interesting how they discoved the crater.

http://www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/Discovering_crater.html

[wolfcreek]

I have no doubt God created the Earth and the universe.

Now we get to study how it all happened,as we should.

[wolfcreek]

I think the *steam* would be pure water not, salty.

[G Larry]

DOH!

I could’a had a V-8! ......HEMI!!!!

[tongass kid]

Alaska Volcano Observatory has a cool web site about the active Alaskan Volcanoes. This is great for home schoolers. Try avo.alaska.edu/

[gleeaikin]

Multiple causes?

I have just finished reading “Comet” by Carl Sagan and Ann Druyan, revised 1997. It contains lots of interesting info about the behavior and size of comets and past and future damage potential for earth. We may be entering a period of more than average activity. Comets even if they are just an airy “snowball” can be seriously disasterous if they are large enough. “The Cycle of Cosmic Catastrophes”, Firestone, et al., 2006, hypothesizes a 300 mile diameter snowball crashing into what became Hudson Bay about 13,000 years ago, destroying the Clovis Indian culture, decimating the large mammal population, and precipitating the 1,000 years of cold called the Younger Dryas. This study also highlights the fact that these extraterrestrial bodies often come in groups as we saw with Shoemaker-Levy strikes on Jupiter recently.

The 34 mya Chesapeake Meteor event, with its 50 mile diameter crater, also coincided with the 60 mile diameter Popigai (sp?) crater in Siberia, the 9 mile Toms River (NJ) crater and a 10 mile crater in Spain.

Regarding the Permian extinction, this newly discovered crater at Antartica could also have occurred along with the better known Bedout crater near Australia. They both occurred enough opposite the Gigantic Siberian Trapps (4 or 5 times the volume of the Deccan) to have caused a reverberation effect through the earth.

It has also been hypothesized that there is a crater 4 or more times larger than the Yucatan crater called Shiva that was of the same time period. This crater appears to be on the West side of India, and if it exists could have been an immediate cause of the Deccan activity. For all we know a large boloid could have struck Siberia and been covered by the Siberian Trappes. Has anyone encountered any recent information about this controversial crater?

[gleeaikin]

I just tried to pull up the web side listed in the Cosmic Catastrophes book. It is listed as www.cosmiccatastrophes.com, and it does NOT work.

I did find another listing referenced on the Googles page which does have interesting info: http://www.perigeezero.org/treatise/index.html

For those who are aware of the hypothesis that Lake Michigan was formed by two boloid strikes, they had a great underwater map. When I read the book it looked to me as if there could have been a smaller strike between the two larger ones, and lo and behold, there on the map is a third smaller depression between the two larger ones. I tried to transfer the map here, but that was beyond my computer skills. Someone else want to try?

[wolfcreek]

The Shiva Hypothesis - Periodic Mass Extinctions

“The Jan/Feb 98 Issue of Planetary Report has an article by Michael Rampino “The Shiva Hypothesis”. This describes a 30 million year cycle of mass extinctions over the past 540 million years (see diagram). One hypothesis is that this corresponds the the solar system oscillating through the galactic plane as it orbits the Milky Way. Rampino notes that the last crossing of the galactic plane occurred a few million years ago and it has been suggested that this led to a disturbance of comets in the Oort Cloud, some of which could now be approaching the inner solar system.”

Our next trip through the Galactic plane: 2012AD

Fascinating. Maybe the Mayans are right?

[wolfcreek]

Try this site and it's links.

http://users.tpg.com.au/users/tps-seti/crater.html

I found it interesting Hawaii volcanoes emit massive amounts of iridium suggesting a mantle piercing impact.

[null and void]

Really? I bet you think it wouldn’t have any silt in it either.

I guess all that mass sorta vanishes when billions of gallons are flashed into steam?

[RichInOC]

...the Earth farts?

[null and void]

For all we know a large boloid could have struck Siberia and been covered by the Siberian Trappes.

The absence of an irridium rich layer at the Permian extinction, and the lack of shocked quartz and other impact related minerals and features (such as shock cones in rock) argue against a major impact triggering the Siberian flows.

Still, one can't help but wonder...

[null and void]

For those who are aware of the hypothesis that Lake Michigan was formed by two boloid strikes, they had a great underwater map. When I read the book it looked to me as if there could have been a smaller strike between the two larger ones, and lo and behold, there on the map is a third smaller depression between the two larger ones. I tried to transfer the map here, but that was beyond my computer skills. Someone else want to try?

This one?

[SunkenCiv]

That was Eugene Shoemaker’s view also, I think (qualifier due to screwing that up before).

[SunkenCiv]

Yeah, that didn’t work for me either (the listed website).

[gleeaikin]

If you look at the direction of the seamounts that go back in time from the Hawaiian Islands, you will see that there is an abrupt turn toward the north in the earliest ones. The change in direction to the present course I think occurred about 43 mya.

[gleeaikin]

Yes this is the Lake Michigan map I saw, you see what i Mean?