New Study: Deccan, not Chicxulub, Killed Dinos

[Schneibster]

Anybody care to speculate on how long the "nuclear winter" was, if it happened? If the planet was in trouble from the Deccan, the asteroid impact would make it worse. Same thing if the sequence is reversed. So a nuclear winter would be bad, but for how long.

My guess is less that three years, because that's how long the reptilians that survived would be able to hibernate.

Estimates I've read on the impact event are in decades; phase II of the Deccan Traps eruptions went on for thirty thousand plus years.

[Faithfree]

Why doesn't it surprise me that Gerta Keller is involved.

I should explain that in a previous life in academia I did lots of research on impact-related stuff and got very familiar with the K-T mass extinction, although I didn't work on that specifically. I think impact as the main cause is a very water tight case, but of course I'm always open to new evidence so it would be interesting to read the actual paper rather than the media hype. The debate about the involvement of the Decan Traps has been very long, very tedious, and previously always toothless, but I'd like to see what the new paper has to offer. Though I doubt I'll be convinced.

The evidence sounds pretty good in this case. There are and have always been timing problems between the Chicxulub event and the beginning of the extinction event in the geological record. And the study of plankton is pretty definitive that there were big problems for a much longer time than the single asteroid strike can explain.

Time for bed now, but I'll post some comments to this tomorrow.

[Schneibster]

Dream well.

[Mysturji]

Is it just me, or does anyone else read "Chicxulub" and think "Chick's Club"?

[JimC]

Is it just me, or does anyone else read "Chicxulub" and think "Chick's Club"?

It's just you, Pervert!

Anyone put out the theory that the impact caused the eruptions?

I don't think it's big enough.

ETA: IIRC the timing's right, though. Chicxulub happened before the second phase of Deccan I think. Part of the problem with associating it directly with the KT boundary is that it's a few hundred thousand years too early.

I'm sure I've read an account in NewScientist that suggested that the impact may have triggered a phase of Deccan, in the sense that if the magma build up was almost ready to blow, the impact could have tipped the balance...

I was thinking that it's pretty much the other side of the world, shock waves hitting a weak point from multiple directions at once.

That was my memory of the speculation I read in NewScientist, a sort of focussing of the waves...

[Svartalf]

Anyone put out the theory that the impact caused the eruptions?

Feels weird... I might go with such an impact triggering major seismic/volcanic activity in its area... but it triggering the same half a wold away... if the impact had been that strong, it's surprising anything multicellular would have survived.

[Horwood Beer-Master]

Is it just me, or does anyone else read "Chicxulub" and think "Chick's Club"?

It's just you, Pervert!

Anyone put out the theory that the impact caused the eruptions?

I don't think it's big enough.

ETA: IIRC the timing's right, though. Chicxulub happened before the second phase of Deccan I think. Part of the problem with associating it directly with the KT boundary is that it's a few hundred thousand years too early.

I'm sure I've read an account in NewScientist that suggested that the impact may have triggered a phase of Deccan, in the sense that if the magma build up was almost ready to blow, the impact could have tipped the balance...

I was thinking that it's pretty much the other side of the world, shock waves hitting a weak point from multiple directions at once.

That was my memory of the speculation I read in NewScientist, a sort of focussing of the waves...

Was Deccan on the other side of the world when Chicxulub occurred?

[Svartalf]

Merka used to be affixed to the Western side of Pangea, and had already drifted a pretty way away from it by the time the KT event happened, so, yep, even then, India was about as far as you could be from Chicxulub at those latitude levels.

[Horwood Beer-Master]

Merka used to be affixed to the Western side of Pangea, and had already drifted a pretty way away from it by the time the KT event happened, so, yep, even then, India was about as far as you could be from Chicxulub at those latitude levels.

So were they in fact antipodes?

[Faithfree]

Merka used to be affixed to the Western side of Pangea, and had already drifted a pretty way away from it by the time the KT event happened, so, yep, even then, India was about as far as you could be from Chicxulub at those latitude levels.

So were they in fact antipodes?

Not exactly, at the end of the Cretaceous the antipode of Chicxulub would have been just off the NW coast of Australia. In any case, the Decan Traps started erupting before the Chicxulub impact so there can be no cause-and-effect. Can't remember the reference, but there are dinosaur bones, eggs etc preserved in the sediments deposited between individual flows of the Decan Traps, so the dinos were doing well living between eruptions up until the extinction.

[Gawdzilla Sama]

Anybody care to speculate on how long the "nuclear winter" was, if it happened? If the planet was in trouble from the Deccan, the asteroid impact would make it worse. Same thing if the sequence is reversed. So a nuclear winter would be bad, but for how long.

My guess is less that three years, because that's how long the reptilians that survived would be able to hibernate.

Estimates I've read on the impact event are in decades; phase II of the Deccan Traps eruptions went on for thirty thousand plus years.

I'm good with that time period, but not with the E.L.E. being nearly that long. If the volcanism had produced lethal conditions for 30K years what life other than that around the black smokers would have survived, especially the large lizards that we know continued on afterwards?

[Faithfree]

Anyone put out the theory that the impact caused the eruptions?

In this case there can't be a connection because the eruptions started some time (can't remember exactly, but perhaps a million years or so) before the extinction. But the idea of huge impacts triggering episodes of volcanic eruptions is a popular idea, particularly among the fringe of the impact research community.

[Gawdzilla Sama]

FF are you familiar with the claims about Hudson's Bay having an impact crater that killed off the megafauna, mammoths, mastodons, etc.?

[Faithfree]

FF are you familiar with the claims about Hudson's Bay having an impact crater that killed off the megafauna, mammoths, mastodons, etc.?

Yep, the idea that Hudson Bay is a huge crater has been around for a long time - I think at least since the 1960s. The very circular nature of arc is the reason for the speculation. But no one have found any actual evidence - like shock metamorphosed rocks.

[Don't Panic]

Anyone put out the theory that the impact caused the eruptions?

In this case there can't be a connection because the eruptions started some time (can't remember exactly, but perhaps a million years or so) before the extinction. But the idea of huge impacts triggering episodes of volcanic eruptions is a popular idea, particularly among the fringe of the impact research community.

I'm making a few assumptions that molten rock is pretty incompressible, and a large impact is similar to a detonation, that would generate a pressure wave radiating away from the point of impact, any weak spots, like where tectonic plates meet would provide an outlet for that pressure.