Double whammy hit dinosaurs

[cran]

Double whammy hit dinosaurs
16.08.05
By Steve Connor
The demise of the dinosaurs was triggered by a spectacular and almost unprecedented double whammy for life on Earth.
New evidence shows that a violent volcanic eruption combined with an asteroid collision for disastrous results.
http://www.nzherald.co.nz/index.cfm?c_id=2...40992&ref=watch ]the story...[/URL]

"Eventually someone will look for the common cause... Leitch and Vasicht (1997) ... or me (2001)"
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[cran]

I seemed to have mucked up the link there, somehow :blink:

[Big Brother Dunk]

Interesting link, thanks.

However, here's the real reason the dinosaurs are extinct:

[projectorion]

They ruled the Earth for 150 million years. Their domination seemed set to last atleast another 150 million. Then they vanish from the fossil record. Just like that. You can even see the line where virtually all dinosaur traces end. We now know this massive extinction wasn't quite as sudden and complete as previously thought. Birds are descended from the great Saurians.

It looks more and more likely it was a combination of events that did lead to the big death. Volcano activity had already pushed many species to the edge of extinction when an asteroid arrived and finished them off. Bad luck I guess.

Why does it seem so unlikely for bad things to happen in pairs? I see double emergencies all the time. Over time such crossfire is inevitable. Bad luck can even come in three's I've heard it told. All you can do is try and be prepared. Supposedly, the Dinosaurs weren't smart enough to colonise space and conquer external threats of this nature.

So what's our excuse? Laziness?

[GOURDHEAD]

It looks more and more likely it was a combination of events that did lead to the big death. Volcano activity had already pushed many species to the edge of extinction when an asteroid arrived and finished them off. Bad luck I guess.

The real source of their bad luck may have been those from whom we have ascended and their blood sucking cousins. Our ancestors may have been aided and abetted by Saurine Spongiform Encephalopathy (SSE). The persistence of our ancestors and those of birds, turtles, and crocidillians seems to indict biological causes for the extinction, again aided by the asteroids and such like.

The extinction of the mosasaurs is the one that defies explanation.

[projectorion]

Mosasaur

Didn't the acidity of the ocean play a role?

[GOURDHEAD]

Didn't the acidity of the ocean play a role?

If so, how did the turtles, fish, and crocidilians survive?

[projectorion]

Higher acidity tolerance maybe. Fresh water animals might have been ok. Big animals like Mosasaurs don't do well in mass extinction events. Not as adaptable as smaller critters. I think I saw a documentary which suggested that they starved.

[CalabashCorolla]

I saw a special on, I think, the Science Channel (U.S. cable/satellite) where a scientist was proposing a "double-whammy" extinction event which involved two meteor strikes anywhere from 300,000 to a few million years apart. Her reasoning for two (Chicxulub being the first of the two) was that the geologic record shows evidence of TWO major impacts...the first one having deposited spherules of compacted rock vapor, and the second having laid down the classic K/T boundary of iridium-enriched rock. Her idea is, Chicxulub heavily weakened the Earth's ecosystems (especially for the dinosaurs) and the second impact finally finished the big guys off.

This actually makes more sense to me than a single impact that supposedly killed off most everything at once. The first impact would have greatly thinned the dinosaur population, allowing a huge niche to open in the environment for mammals and other animals to fill. This would have made life even harder for the remaining dinosaurs, until they were finally wiped out completely by the second impact. The populations of other species would have had time to rebound to the point of no return by the time of the second impact.

The only thing this theory lacks, of course, is evidence of an impact. But then, so did the first impact theory until a certain discovery in Mexico...

[archman]

They ruled the Earth for 150 million years. Their domination seemed set to last atleast another 150 million. Then they vanish from the fossil record. Just like that. You can even see the line where virtually all dinosaur traces end. We now know this massive extinction wasn't quite as sudden and complete as previously thought. Birds are descended from the great Saurians.

Don't forget, there were multiple dinosaur mass extinction events throughout the Mesozoic. The one at the end of the Cretaceous simply got rid of the things once and for all.

The fossil record is rife with mass extinctions. The public is generally only aware of two, the K-T one and the Pleistocene one. Heck, we're undergoing a massive mass extinction event right now.

[The Shade]

Well, the public may only be aware of these 2, but the Permian-Triassic Extinction was, by far, the worst of them all.

http://en.wikipedia.org/wiki/Permian...tinction_event

http://palaeo.gly.bris.ac.uk/Palaeof...ian/intro.html