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Dinosaur Extinction: Rock or Lava? Both?

dee-em
Posts: 6,443
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10/2/2015 3:29:57 AM
Posted: 1 year ago
The competing theories of a large meteor or world-wide volcanic activity may be reconciled by having it both ways:

http://www.smh.com.au...

The end-Cretaceous mass extinction has been the subject of rancorous debates in the scientific world. Until 1980, no one had a solid theory for what triggered the dinosaurs' die-off. Then the father-son team of Luis and Walter Alvarez reported anomalous amounts of iridium in a clay layer right at the geological boundary between the Cretaceous and what is now called the Paleogene Period. Iridium is rare on Earth but common in extraterrestrial objects. They hypothesised a giant impact, and the discovery of the crater remnants a decade later seemed to close the case.

But the volcanism camp persisted. They pointed out the extreme levels of volcanism at the same time as the impact. Was all that lava irrelevant?

Gerta Keller, a Princeton University geologist who has long championed the idea that the volcanism, and not the Chicxulub impact, led to the mass extinctions, said in an email that "there is still the big problem of demonstrating that this impact could have triggered the intense eruptions that led to the mass extinction."
tejretics
Posts: 6,080
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10/2/2015 7:55:10 AM
Posted: 1 year ago
I'm surprised that they weren't reconciled before this.
"Where justice is denied, where poverty is enforced, where ignorance prevails, and where any one class is made to feel that society is an organized conspiracy to oppress, rob and degrade them, neither persons nor property will be safe." - Frederick Douglass
Aran55633
Posts: 109
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10/3/2015 10:22:24 PM
Posted: 1 year ago
Ah, finally a topic I can get really involved in! Thank you for posting this, lol.

It has been understood by most in the field for quite some time that a number of factors contributed to the K-Pg extinction event, as you, Tejretics, expected. The most familiar of these is, of course, the Chicxulub bolide impact.

But the K-Pg boundary event appears to have occurred in the aftermath of no fewer than three separate events, with the third being the terminal asteroid strike. The asteroid may have struck at a point when many groups were already at an extremely low level of diversity, still reeling from the effects of other major changes which occurred on a global level.

The period of increased volcanism which produced the Deccan Trap formations is one of those. In fact, volcanism has been recognized as having played a key role in MANY of the mass extinctions, including three of them "during" the Mesozoic Era, (the K-T boundary event, the T-J boundary event, and the K-Pg boundary event) and the effects of it have been studied in depth.

http://specialpapers.gsapubs.org...

-- There's only a cursory discussion of the K-Pg extinction event, specifically. They spend most of the paper discussing other extinction events, and speaking generally about the effects that such heightened levels of volcanism would have.

The other is the dramatic sea-level recession. One of the most severe periods of marine regression known to modern science occurred during the Maastrichtian for a period of time which may have stretched hundreds of thousands of years, and this would have impacted both marine and terrestrial habitats immensely. Globally, an estimated 11 million square miles (an area of land nearly three times the size of the entire United States) was, at one point or another, exposed by the receding waters.

It's really no wonder that more than 70% of the world's species died out. It is almost more remarkable that so many of them survived.
n7
Posts: 1,355
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10/6/2015 1:35:50 AM
Posted: 1 year ago
They developed warp technology.

http://en.memory-alpha.wikia.com...
404 coherent debate topic not found. Please restart the debate with clear resolution.


Uphold Marxist-Leninist-Maoist-Sargonist-n7ism.
Aran55633
Posts: 109
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10/11/2015 1:00:35 AM
Posted: 1 year ago
At 10/4/2015 4:43:43 AM, Mhykiel wrote:
It was a war with Satan.

It certainly would have seemed like hell on Earth.

But I really do think that it speaks to the tenacity of life on this planet that after these three events, each of which would have been devastating on its own, an estimated 25% of all species managed to survive. It's remarkable.
Akhenaten
Posts: 854
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10/11/2015 11:36:41 AM
Posted: 1 year ago
Although the big extinction events may have been devastating to many species; species die out on a regular basis; even if there is no big event. Thus, the big event, just hurries things up and doesn't really change the general flow of extinction.

https://encrypted-tbn0.gstatic.com...
logical-master123
Posts: 288
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10/16/2015 12:28:21 PM
Posted: 1 year ago
I have reasons why it is both. First their were asteroids which are rock. They bashed up almost everyhting. Then a volcano came and the fog made it cold so everyone died.
Came back to the site :)
TheProphett
Posts: 520
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10/19/2015 11:25:07 PM
Posted: 1 year ago
At 10/2/2015 3:29:57 AM, dee-em wrote:
The competing theories of a large meteor or world-wide volcanic activity may be reconciled by having it both ways:

http://www.smh.com.au...

The end-Cretaceous mass extinction has been the subject of rancorous debates in the scientific world. Until 1980, no one had a solid theory for what triggered the dinosaurs' die-off. Then the father-son team of Luis and Walter Alvarez reported anomalous amounts of iridium in a clay layer right at the geological boundary between the Cretaceous and what is now called the Paleogene Period. Iridium is rare on Earth but common in extraterrestrial objects. They hypothesised a giant impact, and the discovery of the crater remnants a decade later seemed to close the case.

But the volcanism camp persisted. They pointed out the extreme levels of volcanism at the same time as the impact. Was all that lava irrelevant?

Gerta Keller, a Princeton University geologist who has long championed the idea that the volcanism, and not the Chicxulub impact, led to the mass extinctions, said in an email that "there is still the big problem of demonstrating that this impact could have triggered the intense eruptions that led to the mass extinction."


Both. The asteroid happened to strike during a natural cycle of volcanic eruptions, kick starting the process. Mass volcanic eruptions are largely attributed to the Deccan Traps
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