Impact that killed the dinosaurs?

[Lew Rockwell Fan]

I'm not at all current on this subject, but I do recall Gould suggesting that ecosystems in periods of stable climate might become more and more complex with more highly specialized species in tiny niches until they became like a house of cards. Essentially RIPE for some disturbance that brings a massive resorting.

 

[K. Riehl]

Sort of like modern economies who are operating close to the limit of power generation and and who are so dependent on the internet that they would collapse if it was interrupted for any serious length of time?

 

[Lew Rockwell Fan]

Sort of like modern economies who are operating close to the limit of power generation and and who are so dependent on the internet that they would collapse if it was interrupted for any serious length of time?

That comparison seems to me to have merit. Scholars from both fields, econ on the one hand and ecology and evolution on the other, have found useful ideas in the other field for a long time. A tradition that goes back as far as Darwin I believe.

 

[Stephen Palmer]

I'm not at all current on this subject, but I do recall Gould suggesting that ecosystems in periods of stable climate might become more and more complex with more highly specialized species in tiny niches until they became like a house of cards. Essentially RIPE for some disturbance that brings a massive resorting.

That's unlikely. Environment and life are closely coupled.

 

[Lew Rockwell Fan]

That's unlikely. Environment and life are closely coupled.

That sounds very nice. Would you care to explain what it means?

 

[Brian G Turner]

And now there's a project underway to take core samples from the Chicxulub crater:

And - some of the results are in.

And - not surprisingly - it doesn't seem to have been so cataclysmic after all:
Life recovered rapidly at impact site of dino-killing asteroid

For reference, it may also be worth looking at one of our other threads, which discusses the possibility of the impact working with the Deccan Traps eruption to create a global extinction event:
Asteroid + Volcanoes killed off the dinosaurs

It's still not the full story, though.

 

[Vertigo]

I thought that these days it was pretty accepted that they were already in serious decline (climate change?) and that the asteroid impact might just have hurried things along a little but no more than that.

 

[BAYLOR]

I thought that these days it was pretty accepted that they were already in serious decline (climate change?) and that the asteroid impact might just have hurried things along a little but no more than that.

There are some indications the fossil records that the Dino’s were in decline the number of species were getting fewer. I think that had the asteroid hit the Dino’s might have lost their dominance on earth mamamals anyways, but I Think there would be some of them still around today. And perhaps the marine reptiles would have survived to or at least some of them. The Amonites as well.

 

[Venusian Broon]

I thought that these days it was pretty accepted that they were already in serious decline (climate change?) and that the asteroid impact might just have hurried things along a little but no more than that.

I agree, it was probably a very bad day* for a range of species that were probably struggling a bit anyway!

I think at the time of the asteroid extinction theory (the 1980s or thereabouts), there was no evidence of dinosaurs above the KT boundary. Since then I think a few fossils and evidence has turned up, that might show that the decline was pretty drawn out, with some dinosaurs surviving. Well, not drawn out in geological times, but hundreds of thousands of years after the asteroid.

There has been a lot of work trying to tie other extinctions to other asteroid impacts, but actually it seems extinction events and asteroid impacts aren't particularly correlated. It is possibly because it really depends what the asteroid hits. The Chicxulub hit is likely to have generated a massive amount of carbon dioxide because of the rock it hit. Hence after the nuclear winter there would have been a massive greenhouse effect. Great for really sorting out the men from the boys, species-wise. However other much bigger asteroids have hit different rock types and doing...meh

-----------------------------------------------
* The 'fact' about the Chicxulub strike that I most remember, is that it probably generated a Tsunami 100 metres high...however that was because it fell in shallow seas...if the asteroid has hit deep water it would have easily generated a Tsunami 4.6 kilometres tall

 

[BAYLOR]

As great as the dinosaurs extinction was , It pales in comparison to the Permian extinction event of 250 million years ago. That one was the greatest extinction event of all time because 90 percetn of everything that lived on earth died.

 

[Stephen Palmer]

Highly recommended:

 

[J Riff]

I think it's probably all wrong - but makes for some great movies.

 

[Luiglin]

And - some of the results are in.

And - not surprisingly - it doesn't seem to have been so cataclysmic after all:
Life recovered rapidly at impact site of dino-killing asteroid

For reference, it may also be worth looking at one of our other threads, which discusses the possibility of the impact working with the Deccan Traps eruption to create a global extinction event:
Asteroid + Volcanoes killed off the dinosaurs

It's still not the full story, though.

Don't tell the Dark Lord. He's been peddling the asteroid impact theory for their extinction for years. Also don't tell him that I told it in a 75 entry a few years back

So long and thanks for all the big fanged lizards

"When it closes?"

The Minion's fingers exploded out.

"Huge?"

The hand nodded.

"Excellent. We don't need any more big fanged lizards. Pity there's no intelligent life. There'll be no witnesses to my evil, no people to gloat over or cower at my power. Damn shame."

The portal disappeared with a feint pop.

~~~

Elsewhere, on a insignificant blue planet, the age of the dinosaurs ended in a cataclysmic bang; impressing the mammals and baffling their descendants.

 

[Matteo]

Highly recommended:

Brian, don't read the back blurb...

And Stephen, thanks for post - looks interesting.

 

[Brian G Turner]

The opening sentence is anathema, but the rest sounds interesting.

 

[BAYLOR]

The opening sentence is anathema, but the rest sounds interesting.

Its a terrific !

 

[Brian G Turner]

I thought that these days it was pretty accepted that they were already in serious decline (climate change?) and that the asteroid impact might just have hurried things along a little but no more than that.

So you'd think, but I've consistently read in the science press that the extinction event was mainly due to an asteroid impact, and not surprisingly this feeds back into the mainstream press to ensure it remains an established popular opinion.

In the meantime, I'm showing bias by agreeing with this piece - which claims that if you take human bias out of the equation, the evidence points exactly to what I originally argued - that the volcanism of the period effectively killed the dinosaurs, and the impact was just icing on an already thick cake:

Study removes human bias from debate over dinosaurs' demise

To help resolve the scientific debate over whether it was a giant asteroid or volcanic eruptions that wiped out the dinosaurs and most other species 66 million years ago, Dartmouth researchers tried a new approach—they removed scientists from the debate and let the computers decide.

phys.org

 

[Ursa major]

and the impact was just icing on an already thick cake

I can see the headline now:

Claim that Diabetes Killed the Dinosaurs!​

 

[JimC]

"Recent articles on the impact theory have stated that the Chicxulub event would not have had sufficient energies to cause the global devastation postulated in the classic model,"

What is the energy range currently estimated for the impact?
How many simultaneous Tzar Bombas would that be equivalent to?
I could calculate those numbers myself - but I'm lazy.

Some dinos did survive - we call 'em birds.
As an aside, the effects of the impact were the primary reason for the demise of the pterosaurs (they were not dinos). I would expect that large and small, they were most likely gone worldwide within a month of the impact, possibly less. There were no large soaring birds before the impact, but for the obvious reasons, I would expect small birds to to make it through when pterosaurs couldn't. It took large soaring birds 5 to 10 million years to develop after the pterosaurs were gone.

BTW, this is me out in my front yard holding the left humerus of one of the larger Late Cretaceous pterosaurs. Shoulder is in my right hand, elbow in my left.

 

[JimC]

BTW, I was curious enough to hurredly run some very approximate numbers for the Chicxulub impact. If the energy were distributed uniformly over the entire world, no matter where you are, land or sea, it would be like standing within one and a quarter miles of four Hiroshima bombs. That wouldn't be enough energy to put anything at risk.....

I did this very quickly and didn't check it, so feel free to point out potential errors.