The Theory That Volcanoes Killed the Dinosaurs Is Officially Extinct

“Sixty-six million years ago, all dinosaurs (except for birds) were wiped from the face of the Earth…” writes Gizmodo. “What’s indisputable about this pivotal moment in Earth’s history is that a 6.2 to 9.3-mile-wide (10 to 15-kilometer) asteroid struck what…

Full Article

Follow Slashdot blog updates by subscribing to our blog RSS feed

Nickname:

Password:

Nickname:

Password:

The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.

A 5c drop in global temperatures would be very ecologically damaging. 30,000 years is not enough time for biodiversity to recover. I would expect that while those volcanoes didn’t wipe out the dinos, they likely had some kind of significant effect on the outcome of the asteroid strike that followed. Hell, maybe it increased the survival rate by having pre-selected for animals and plants that were more cold and starvation tolerant. Maybe without those eruptions, the ancestors of today’s birds wouldn’t have made it. Your nuanced take is more likely to be correct than their simplistic model. Also the idea that an astroid with that much kintic energy could slam into the crust and not set off all the volcanoes around the globe that would have erupted independently in the next decade due to structural instability just seems silly. “It’s complicated” is far more often true than “single causal factor”. if everything above the 55th degree is wiped out, is that really a mass extinction? sounds like plenty of time to repopulate. e.g. at the end of the last ice age humans literally followed the ice sheet’s withdrawal north. Well, yes, that’s a mass extinction. But it’s not just one area getting wiped out, it’s climate change for the entire globe. And it’s not just climate change for the entire globe, but rapid onset climate change for the entire globe. Sure, 5c isn’t like everything everywhere would have dropped dead, but there would have been significant habitat shifts and reductions in biodiversity as all the species that couldn’t cope died out. Evolution (and species migrations) take time to fill empty niches with replace if something dies, something else takes its place. if anything caused a major loss of biomass it’d guess the sun being blacked out would be the cause. a 5c drop where it’s hot doesn’t do much. As long as there’s soil. I suspect this will surprise you: Global climate is a massively complex interconnected system. You are oversimplifying to the point your model is useless. A 5c drop in global temperatures would be very ecologically damaging. 30,000 years is not enough time for biodiversity to recover.

You have just described the magnitude and speed of a typical ice age. Biodiversity handled those just fine. Obligatory Gary Larson. It was your asteroid. Happy holidays everyone =] An earlier bunch of volcanoes caused previous mass extinctions. The asteroid caused the cretaceous extinction event. There was another extinction at the beginning of the Jurassic period, but the biggest one was between the Permian and the Triassic period. Continental drift led to really big volcanic events, and 90% or so of species disappeared. The current mass extinction (the 6th) is being caused by humans. Where was (what is now) India at the time? Had it already rammed (what is now) Asia or was it still on its way north? But the timescale is just trivial to the point of near irrelevance. The Deccan LIP (Large Igneous Province) – or “plateau basalts”, or “Traps”, to use two other names for the same set of rocks recording the same events – was running for around 2 million years before the Chicxulub impact, and maybe a million years after. Nobody is disputing that the Chicxulub impact was a bad day for life on Earth, but the question remains : would it have had the same level of effect if life hadn’t been subjected to 60 times as long a period of sporadic significant volcanigenic climate changes before the impactor (we can discount the changes after the impact).

Remember the “Great Dying”? Permian-Triassic or Palæozoic-Mesozoic boundary ; 4% survival at the genus level versus about 25% survival across the Mesozoic-Cænozoic boundary. Big event. Ascribed, at different times in my career to the Siberian “traps” (LIP, etc), to the Manicouagan (CA) impact (with possibly simultaneous Boltysh (UK) and Rochechouart (FR) impacts). and to (flavour of this last decade or two) an oceanic anoxic event. Or, all three occurring too close in time to be distinguished in the fossil record. BIG event. Well, the most recent dates (last few years ; I only noticed the date revisions a couple of weeks ago) put Manicouagan about 30 million years (~12% relative to today) after the “Great Dying”, so probably not at all related, while Boltysh and Rochechouart are at different times even more recently (so the putative “3-crater chain” beautiful hypothesis is slain by the ugly fact of the dates, now we’ve got better dates), leaving the Siberian plateau basalts combined with the oceanic anoxic event as the remaining hypothesis on the table (since most people put the Traps as triggering the anoxic event after thrashing the climate up and down for for a million-odd years).

Just to put that into context : the last climate event comparable to the one we’re producing today took about 120,000 years (1/8th of a million years) for natural processes to restore the atmosphere to something like it’s pre-CO2 injection state. So, assuming we stop pumping CO2 into the atmosphere tomorrow, we’re probably on track for 1/8th of a Mesozoic-Cænozoic boundary extinction. Noticeable, but probably not era-defining. (Of course, if we don’t stop pumping CO2 into the atmosphere tomorrow – very likely – then the total level of change goes up.)

We (Earth ; it’s residents) get hit by substantial impactors at relatively frequent, irregular intervals. Most of them don’t trigger a major extinction (except for those species confined to the impact zone, who get an opportunity most planetary scientists would consider, briefly, before passing up). LIPs/ “trap eruptions”, “plateau basalts” are pretty common too. And most of them only produce modest extinctions. But on those rarer occasions when you get an impactor land at random in the middle of a LIP sequence … you can either get a little extinction or a big extinction (Mesozoic-Cænozoic boundary versus Palæozoic-Mesozoic boundary). For those wanting comforting predictions on predictable laws, your comfort is that it could randomly happen tomorrow. Or it might not. Sleep easy, and learn to knap hand axes yesterday not tomorrow. Is America asleep?

Oh, don’t tell me – some news item of earth-shattering importance? Should I turn the radio on? Practice hand-axe knapping? We (Earth ; it’s residents) get hit by substantial impactors at relatively frequent, irregular intervals. Depends on what you consider “substantial”. If by that you mean Chicxulub-impactor levels of substantial, 1E23 Joules: not “relatively frequent”. We (Earth ; it’s residents) get hit by substantial impactors at relatively frequent, irregular intervals. Depends on what you consider “substantial”. If by that you mean Chicxulub-impactor levels of substantial, 1E23 Joules: not “relatively frequent”. Gizmodo is now a reliable source? Compared to CBS, NBC, ABC, PBS, FOX, CNN, The NY Times, etc, etc, yes it is. No, I’m not happy every news organization out there has perjured themselves for either ratings or ideological purity, but there you are. There may be more comments in this discussion. Without JavaScript enabled, you might want to turn on Classic Discussion System in your preferences instead. Albania Will Close TikTok for One Year, Saying It Encourages Violence Among Children Sea Levels are Already Rising in America’s Southeast. A Preview of the Future? “Truth never comes into the world but like a bastard, to the ignominy

of him that brought her birth.”

— Milton

Read more at the source