Poison gas 'caused' great dying

[DoYouEverWonder]

5 December 2005

The Earth's greatest mass extinction was probably caused by poisonous volcanic gas, according to a study published in the journal Geology.

<snip>

The authors of the Geology paper believe volcanic gases from the eruption would have depleted Earth's protective ozone layer and acidified the land and sea, killed rooted vegetation.

This would have hindered the retention of soil and allowed it to be washed into the surrounding oceans.

Soil materials in the oceans would have blocked out light and soaked up oxygen. Analysis of rock chemistry suggests that after the so-called "soil crisis" on land, the marine ecosystem succumbed to the stresses of environmental change.

Oceanic life faltered, completing a global catastrophe.

http://news.bbc.co.uk/2/hi/science/nature/4499722.stm

Hate to say this, but it looks like history might be repeating itself, except this time we're the ones cutting all the gas.

[benburch]

1. This isn't conclusive...

And other evidence, especially from the Karoo rocks of South Africa seems to contradict it. But such is science. This idea might be the right one.

[greiner3]

2. I don't have a link but;

I remember an article within the year that said after a large asteroid hit the Earth, it caused a great many volcanos to erupt all within the same time frame. Cause and effect?

[Dead_Parrot]

3. The K-T event?

I seem to recall the end of the dinosaurs was linked to a (non-asteroid-related) rise in volcanic activity. On it's own, species might have able to adapt fast enough but they were on the brink anyway when an asteroid hit pushed them over.

I may be totally wrong, however, so this is probably no help at all. :)

[General Paranoia]

4. Asteroids vs Volcanoes

Over the years it seems like to me that Geologists & Paleontologists have a not-invented-here problem with the impact theories. Or it may be a they-don't-have-a-license to be in my field.:grr:

It amazes me that they seem to think a huge volcanic eruption would somehow trump any possible impact. How about looking up some night at the moon. Pretty sizable impact chopped that puppy out of the earth. In the process there was probably some incidental volcanism - if you can call molten lava waves hundreds to thousands of miles high "volcanism". When I first heard about the Chicxulub crater in the Yucatan I immediately ran to a globe to see where India was (Deccan Flats eruptions). Nicely around the other side of the planet even when you account for continental drift. You would expect to find more than a little disruption in the crust on the other side of the earth in line with the original trajectory through the impact crater. It doesn't need to be exactly 180 degrees unless the impact is dead center. I have yet to have heard about any volcanoes on earth that have been able to put significant chunks of material into orbit but this is exactly what many impacts have done. :shrug:

I believe the Permian has at least one good candidate crater off Australia.

The following is a good link:
http://www1.tpgi.com.au/users/tps-seti/crater.html

:thumbsup:

[Odin2005]

5. The KT extinction was a result of 3 events coinciding.

Asteroid impact
Lots of vulcanism in India and the Rockies
A major drop in sea level.

Major impacts only cause extimctions if the biosphere is already stressed. There are many large impact craters that are not asocciated with mas extintions (a crater in Iowa and the crater under Chesapeake Bay are good examples of major impacts not connected to extinctions.

[Dogmudgeon]

6. I don't think the answer is known for sure

Not just the K-T event, but the P-T (Permian-Triassic) event, as well as the climate change during the Miocene circa 50 MYA.

Some astronomers have hypothesized a planet with a 27 MY long period -- "Nemesis" -- but the stronger evidence is for the movement of the Solar System through regularly-spaced clouds of cosmic dust and debris. The major period seems to be about 150 MY, with shorter periods intermixed. Some of the afore-mentioned "dust" can be the size of a city or two, and collisions with a planet (e.g., Earth) will have the expected cataclysmic effects. Whatever whacked into Mars tore half its surface away; a similar impact upon Earth would surely destroy all complex multicellular life.

But the regular-sized space dust can have significant effects all its own: decreases in insolation, changes in orbital and rotational elements from drag, changes in albedo, and (according to theories of panspermia) the possibilities that exotic new micro-organisms will reach the Earth in much greater numbers.

Charles Pellegrino, author of Her Name, Titanic (one of the influences on James Cameron), also wrote a novel called Dust, about the cosmic dust theory. It received good reviews but little attention; I think it's Pellegrino's first hard sci-fi novel (Pellegrino is a physicist, IIRC). It's a pretty good read if you can still find it. And look for Her Name, Titanic while you're at it -- it's an under-appreciated classic, one of the best pieces of modern popular writing I've read.

In general, we've really just started work on this part of the field, since Hoyle, Napier and Clube, and Alvarez (et al.) revived catastrophism with a strong scientific basis. Catastrophes are not mandatory for extinction events, but the evidence from data is strong in nearly all cases looked at. However, what the data say exactly is still under debate. A whole lot of debate.

And then there's the catastrophe of intelligence ...

--p!

[Oerdin]

8. That is theorized

based upon a tremendous amount of basaltic lava which was formed at this time. The most accepted theory is that a large asteroid hit the Earth fracturing the crust and causing massive volcanic eruptions.

[happyslug]

7. This is the great Permian extinction, NOT the Dinosaur Extinction.

Some more on the Great Permian Extinction:
http://hannover.park.org/Canada/Museum/extinction/permass.html

http://www.nationalgeographic.com/ngm/0009/feature4/

http://geology.wcedu.pima.edu/~jkarlovitz/febpage2.htm

Guideline to Scientific Periods:
http://www.ucmp.berkeley.edu/help/timeform.html

(mya = million years ago)

Precambrian (4,500 to 543 mya)

......Hadean (4500 to 3800 mya)
......Archaean (3800 to 2500 mya)
......Proterozoic (2500 to 543 mya)
............Vendian (650 to 543 mya)

Phanerozoic (543 mya to today)

.......Paleozoic Era (543 to 248 mya)
.............Cambrian (543 to 490 mya)
.....................Tommotian (530 to 527 mya)
.............Ordovician (490 to 443 mya)
.............Silurian (443 to 417 mya)
.............Devonian (417 to 354 mya)
.............Carboniferous (354 to 290 mya)
...................Mississippian (354 to 323 mya)
...................Pennsylvanian (323 to 290 mya)
.............Permian (290 to 248 mya)
-------------------------THE GREAT PERMIAN EXTINCTION-----------------
.......Mesozoic Era (248 to 65 mya)
.............Triassic (248 to 206 mya) (First appearance of Dinosaurs)
.............Jurassic (206 to 144 mya) (First "Age of Dinosaurs")
.............Cretaceous (144 to 65 mya) (Second "Age of Dinosaurs")
-----------------------------------THE K/T Border---------------------
........Cenozoic Era (65 mya to today) ("Age of Mammals")
..............Tertiary (65 to 1.8 mya)
....................Paleocene (65 to 54.8 mya)
....................Eocene 54.8 to 33.7 mya)
....................Oligocene (33.7 to 23.8 mya)
....................Miocene (23.8 to 5.3 mya)
....................Pliocene (5.3 to 1.8 mya)
..............Quaternary (1.8 mya to today)
.....................Pleistocene (1.8 mya to 10,000 years ago)
.....................Holocene (10,000 years ago to today)