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.

[wolfcreek]

Not sure we could replicate that in a lab. I know rain sometimes has dirt and dust in it due to updrafts from thunderstorms but, steam might be another case. Not sure mist would be able to hold much material.

[wolfcreek]

I don’t thinks it’s a coincidence we have mass extinction events every 50 million years or so. (see charts on post #52 website)

Doesn’t make me feel good that we might have one coming up soon. Also makes me wonder how advanced humans became in between events in the past.

[null and void]

I see three distinct deep areas, in the locations you describe.

They don’t look particularly round/impact like to me. But a little tectonic squishing and an ice age or two could account for that.

This would be a good place for a PhD candiate to take some core samples!

[null and void]

Not sure we could replicate that in a lab. I know rain sometimes has dirt and dust in it due to updrafts from thunderstorms but, steam might be another case. Not sure mist would be able to hold much material.

I looked over my last post to you. Wow. That was pretty harsh! Sorry. it sounded much much worse than I intended. Yikes.

You are correct in that a well tempered evaporation or slow boil would have very little in the way of disolved solids. This is, after all, how one distills water or liquor.

But this is anything but a gentle boil, it was a wall of sea water trying to flood into a hundred mile wide white hot crater. This instantly flashed the water that touched the molten rock to live steam, so much steam that the edge of the ocean was held back from filling the hole for days. This was a days long steam explosion with the live steam shredding sea water off of the encroaching walls and blasting it and any mud it carried up into the stratosphere and near space to be distributed around the globe.

It is a recipe for pasteurized planet. That local heat gets carried world wide by the steam, as does the dirt and dissolved salts.

Compare this to the relatively gentle boiling a moonshiner does. Even with the slow, even heating a moonshiner needs a 'thump keg' to catch any chunks blown out of the mash by the heating process:

A large white hot crater? Well...

[null and void]

Also makes me wonder how advanced humans became in between events in the past.

Me too!

[SunkenCiv]

:') What you said.

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The Cycle of Cosmic Catastrophes: Flood, Fire, and Famine in the History of Civilization by Richard Firestone, Allen West, and Simon Warwick-Smith

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[gleeaikin]

According to the Firestone, et al. hypothesis, the impactors came in at a low angle from the north. This would have left the eliptical gouges shown in the lake. Also since this would have been an ice/snow ball comet rather than a rock or metal meteor, the crash signature is quite different. Shallower craters, less of a rim, not necessarily a slight mound in the center are their characteristics.

By all means read the book, it is fascinating, and the authors go into great and lucid detail on their scientific testing methods.

[wolfcreek]

That’s definitly the first time I’ve see how a still works. LOL!

You’re probably right about the salt and other debris super-heated by the impact area. Would be even worse for a mantle buster.

[null and void]

Yeah. Chicxulub was pretty close to that!

"Scaling laws place the depth of the transient cavity at 35-40 km below the transient crater rim for the Chicxulub impact crater (Morgan et al., 1997). This depth suggests that deformation from the impact may have reached the base of the crust,..."