From the AGU:
Global fires after the asteroid impact probably caused the K-Pg extinction
About 66 million years ago a mountain-sized asteroid hit what is now the Yucatan in Mexico at exactly the time of the Cretaceous-Paleogene (K-Pg) mass extinction. Evidence for the asteroid impact comes from sediments in the K-Pg boundary layer, but the details of the event, including what precisely caused the mass extinction, are still being debated.
Some scientists have hypothesized that since the ejecta from the impact would have heated up dramatically as it reentered the Earth’s atmosphere, the resulting infrared radiation from the upper atmosphere would have ignited fires around the globe and killed everything except those animals and plants that were sheltered underground or underwater.
Other scientists have challenged the global fire hypothesis on the basis of several lines of evidence, including absence of charcoal-which would be a sign of widespread fires-in the K-Pg boundary sediments. They also suggested that the soot observed in the debris layer actually originated from the impact site itself, not from widespread fires caused by reentering ejecta.
Robertson et al. show that the apparent lack of charcoal in the K-Pg boundary layer resulted from changes in sedimentation rates: When the charcoal data are corrected for the known changes in sedimentation rates, they exhibit an excess of charcoal, not a deficiency. They also show that the mass of soot that could have been released from the impact site itself is far too small to account for the observed soot in the K-Pg layer. In addition, they argue that since the physical models show that the radiant energy reaching the ground from the reentering ejecta would be sufficient to ignite tinder, it would thereby spark widespread fires. The authors also review other evidence for and against the firestorm hypothesis and conclude that all of the data can be explained in ways that are consistent with widespread fires.
Source:
Journal of Geophysical Research-Planets, doi:10.1002/jgrg.20018, 2013
http://onlinelibrary.wiley.com/doi/10.1002/jgrg.20018/abstract
Title:
K/Pg extinction: Reevaluation of the heat/fire hypothesis
Authors:
Douglas S. Robertson: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA; William M. Lewis: Department of Ecology and Evolutionary Biology and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA; Peter M. Sheehan: Department of Geology, Milwaukee Public Museum, Milwaukee, Wisconsin, USA; Owen B. Toon: Department of Atmospheric and Oceanic Sciences and Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, USA.
What’s the chances of the big one hitting right on the Cretaceous /Tertiary boundary, eh?
And what do you get when you burn things? CO2!!! The demon gas strikes again.
Interesting coincidence isn’t it Jimmy Haigh! This site is the only known source of blue pectolite, usually a grayish material. The blue makes a fine semi-precious stone, a mix of translucent blue and white. It is pretty hard and works and polishes similarly to jade.
Jimmy, you’ve hit the nail on the head. Proof, as if more were needed, that greedy corporate American interests will do *anything* to ruin the environment…
NOw that’s what I call global warming…
Jimmy Haigh. says:
March 27, 2013 at 4:33 am
What’s the chances of the big one hitting right on the Cretaceous /Tertiary boundary, eh?
A case of the Egg hitting the Chicken, eh?
I have heard that it was the Dekkan traps volcano eruption that killed them. Does that create Co2 as well?
Interestingly the only geologist on the paper was the third author. The KT boundary discussion (now I’m showing my age as I prefer the KT monika) is many years old. The related extinction event took several million years and this is shown in the fossil record. Global wildfires would have caused an immediate (in geological terms) fingerprint. One that does not exist in the said record.
We are now capable of stopping such an event-with adequate warning. but we must spend money for the prevention of a Chimera outbreak….
I await any follow up papers.
I think they’re wrong. Recently scientists have uncovered fossilized SUV’s and coal fired power plants. The evidence is mounting that Global Warming controls everything.
You can see a CO2 spike ~ 66 million years ago in this stomata study. This study shows CO2 much higher in the past than now.
http://www.sonoma.edu/users/c/crocker/516-2011/300myr%20profile.pdf
So what killed those dinosaurs that lived in the sea?
A layer rich in carbon was recorded from the classic K/T (K/Pg) site at Stevn’s Klint in Denmark. It was referred to by Hans Joergen Hansen (Univ. Copenhagen) as the “grey chalk” and has been used by some researchers as evidence of the post impact fire storm. Detailed sedimentological analysis shows that the carbon content includes 1-2 micro diameter hollow graphite spheres, known only from volcanic glasses. The depositional period of the “grey chalk” has been calculated by H.J. Hansen as approximately 600 thousand years. As he once said on a field excursion, “If we could find the wood that burns that long, then the energy problems of the world would be solved.”
A meteorite created the Sudbury Basin 1.85 billion years ago in Northern Ontario, Canada. A second meteorite struck the eastern edge of the same area about 40 million years ago in what is now Lake Wanapitie. This led one geologist to conclude that God has a very good aim but a very poor memory.
Somehow, I feel it’s all my fault.
“So what killed those dinosaurs that lived in the sea?”
Salty diet. They all got hypertension.
DaveF,
Any disruption in the food chain will eventually find it’s way to the larger animals.
Most of our fossil record comes from sea creatures and especially shell fish. They also became extinct in vast numbers which is how we know of the extinction, not from land based animals which are very rarely fossilised. I think therefore that fires are unlikely to be the cause.
I thought it was a flood.
DaveF says:
March 27, 2013 at 5:46 am
So what killed those dinosaurs that lived in the sea?
Burning trees caused CO2 levels to increase, which caused sea levels to rise dramatically and they all died from vertigo.
Sure. The models show that. However, what other possibilities exist?
First, look at the current understanding of the Chicxulub impactor. It appears to have been about 6 miles in diameter, and left visible rings at 40 miles and 110 miles in diameter. An exceptionally thick layer at 4200 feet deep was part of the discovery, and there is displaced material that indicates a “kilometers high” tsunami, which is to be expected from such a powerful impact. Imagine that volume of water washing away in all directions, and be glad that nothing like this has happened recently. It seems likely that any combustible forest for a long way away would have been stripped bare and carried away.
Second, consider the incredible energy that has just been expended on the crust, sending ringing shock-waves around the planet like a bell had been rung. Any weak spot would soon be volcanic, and who’s to say just how much of the mantle was exposed? Was the crater a gaping, smoking hole for years afterward? We’ve seen just how much material is ejected from a single volcano (Pinatubo comes to mind, and Mt. St. Helens), just multiply that by an unknown but large number. The entire planet was likely blanketed by soot and ash as a direct result, and possibly for decades.
Third, we’ve now seen the Chelyabinsk event, recorded on video from multiple angles. That was a very high relative speed event, and I didn’t see any evidence of ground structures bursting into flames. Ejecta from the Chicxulub impact that cleared the atmosphere and came crashing back would not have the same kind of relative speed, thus less chance of igniting the forests (which were probably washed away).
I like playing “imagine if” games as much as anyone, but the conclusions I’m reading here seem like they’re all on the outside of probability. Nothing seems to take away the most likely current theory, that the extinction event was caused by dramatic and rapid cooling caused by the impact itself, not giant forest fires. Although I don’t doubt there were fires from the impact, and it’s nice that they measured all the soot.
One thing IS certain… we can theorize and hypothesize and imagine all we want, but NOBODY knows for sure exactly what happens when an impact of that magnitude occurs. And if we’re lucky, we never will.
@ Dave F
“So what killed those dinosaurs that lived in the sea?”
They died of heatbreak following the death of all their mates on land. 🙂
DaveF says: March 27, 2013 at 5:46 am “So what killed those dinosaurs that lived in the sea?” Ahhh, evolution, they crawled onto land, on their fins/legs that became legs/wings, to occupy vacant niches?
DaveF says:
March 27, 2013 at 5:46 am
So what killed those dinosaurs that lived in the sea?
—
Between the impact and the fires, dust and smoke would have decreased sunlight significantly for months to years. That would have dramatically reduced plankton populations, plus the animals that feed on them. Which is pretty much everything, directily or indirectly.
The ionization radiation created from the passage of the object through the atmosphere would also be responsible for a wide swath of death. Certainly it wouldn’t reach around the world, but it would have sterilized along its path. The amount would be dependent on its inbound trajectory.
Probably the weak point in this hypothesis is the modeling to determine the amount of radiation from the re-entering ejecta and the global distribution of that ejecta. I think the empact side of the globe should show greater signs of fires than the other side.
“So what killed those dinosaurs that lived in the sea?”
SPONGE-BOB-SQUARE-PANTS!
(Sorry, couldn’t resist……)
See this presentation for an alternate explanation of what happened…
http://www.threeimpacts-twoevents.com/wp-content/uploads/2013/01/SIMULTANEOUS-IMPACTS-3JAN2013-WEBSITE.pdf
Mike Bromley says “the egg hitting the chicken”.
Excellent response to Jimmy’s comment. I was thinking something similar.
OT sounds like you were contracting in Kurdistan, a place familiar to this rock doctor.
DaveF says:
March 27, 2013 at 5:46 am
So what killed those dinosaurs that lived in the sea?
===========================
Strictly speaking, there weren’t any marine dinosaurs that we know of. There were however, a number of large marine reptiles. Crocodiles and turtles survived. icthyosaurs died out before the end of the Cretaceous. Pleisosaurs and Mosasaurs probably were victims of the KT extinction event.
And why didn’t certain environmentally sensitive amphibian and reptile species die out?
AleaJactaEst says:
March 27, 2013 at 5:21 am
Interestingly the only geologist on the paper was the third author. The KT boundary discussion (now I’m showing my age as I prefer the KT monika) is many years old. The related extinction event took several million years and this is shown in the fossil record. Global wildfires would have caused an immediate (in geological terms) fingerprint. One that does not exist in the said record.
==================================
Yes.
And, related, massive vulcanism is thought to be a factor in the PT (Siberian traps) and KJ (“Newark Traps”) extinction events. Major vulcanism was also underway in India (Deccan Traps) at the time of the Chixulub impact. An Iridium layer has been found in the middle of the Deccan lava beds — presumably from the Chixulub event.
I’d like to know if the authors of this paper mapped out possible ejecta trajectories. The trajectories vary with the impact velocity and direction of course. My best guess, and it is a guess, is that very little of the ejected material was likely to make it to Australia, South and East Asia as I think that the vast majority of possible trajectories bring the material down rather quickly on the half of the planet centered on the impact site. Fires on that side? Seems quite plausible. Fires of the opposite side? Not so much I’m thinking.
Something that always concerns me is the total lack of fossils at the boundary, With everything dying at the same time why the lack of fossils?
Luther Wu says:
“Somehow, I feel it’s all my fault.”
Don’t worry about it, Luther. I have it on good authority that it is Bush’s fault.
The meteor didn’t find the K/Pg boundary, it defined it. A well defined spike in 12C after the event indicates lots of things were dead. Dead things burn. These guys are just Carbon wags working every angle of their failed model, in this case downwelling Ir, for PR.
@ Jeff Alberts: Ah, the frog problem. Yes, environmentally sensitive species survived. You could make the argument that they were “wet” and thus spared from the fires. However, it’s more difficult to continue the argument in the face of loss of vegitation, which is necessary for the reproduction of their primary food source: bugs.
One thing that frogs do not have in common with dinosaurs is migration. Large species move around and interact with lots of other species. Frogs don’t. I’ve always felt that the demise of the dinosaurs was something more akin to a plague than a natural disaster.
Complete nonsense, as is expected from AGU, a lost cause of a group. What this is an example of is the popular science mentality of career under-achievers who never miss an opportunity to take a dump on hard science. Sounds to me like yet another Omni magazine dramatization of true science, in this case the groundbreaking KT discoveries of Alvarez.
Yes, there were fires, perhaps even global fires, but plants and animals have evolved in a world where fire is a common occurrence and adapted to survive. What they didn’t adapt to survive was the shutting down of the food chain, attacked from below with photosynthesis being taken out of play from months or years of no sunshine. What few plants managed to survive in a low sunlight environment would have been picked clean by starving animals until they were completely gone. As this crept up the food chain extinctions occurred. Eventually the sun would shine, seeds would again germinate, but the higher order animals are already gone, for good.
It must kill these amateur pop-sci pretenders at AGU that all the real groundbreaking discoveries of the last century by actual scientists, such as Milankovic, Wegener and team Alvarez were initially scoffed at but later vindicated, and I’d bet AGU was part of that peanut gallery in each and every case.
NASA and AGU and their peers like Sagan, Hansen and Mann always try to take hard science and divert us with science fiction.
When I was doing geological mapping in Eastern Venezuela in 1995 I mapped the Cretaceous/Tertiary boundary. There was nothing there – just a deepwater shale on shale contact. I think the theory is that the asteroid came in from the south east over the top of paleo-Venezuela and landed in the Paleo-Yucatan.
A few years later I was working with some geophysicists in Aberdeen who had identified a possible meteor crater in the North Sea which, as close as it can be dated, is also right at the Cretaceous/Tertiary boundary.
http://en.wikipedia.org/wiki/Silverpit_crater
Luther, we’re big on apologies here in Oz …would you feel better if you apologised to the descendants of the dinosaurs ….?
No central uplift peak?
Okay, I’m fussy about the painting. It’s science. We’re supposed to be fussy.
An impact that big would send a tsunami up the Cretaceous continental sea from the Gulf of Mexico to the Arctic, one would think. I live in Alberta; out at Drumheller, you can see the Cret-Tertiary boundary in the valley wall (just above the last dark line of a coal stringer). It holds, apparently, the Iridium layer of Alvarez. However, no tsunamic debris OR (more signficantly) an erosive surface.
A “small” seaquake has a tsunami that crosses the Pacific. A global ‘quake stays where it is.
Something is off. Again.
OK, I’ll play along. The only marine dinosaurs were seabirds, most of which perished along with their terrestrial kin at the K/T boundary. But not all. Modern Aves appears to descend from an unusual group of Cretaceous shorebirds which survived extinction, probably in the southern hemisphere.
And now for something different: geological nomenclature. My opinion doesn’t count, but many geologists share objections to replacing the Tertiary with the Paleogene & Neogene Periods, for various reasons. My problem is more with how the IUGS has split up the Tertiary than to getting rid of it. Reasons for doing so I’ve read are that, at 63 million years (65.5 to 2.6 Ma), the Tertiary was too long, & that finer detail of the geologic record in the Cenozoic Era (65.5 Ma to present) justifies shorter periods.
The Tertiary however was much shorter than the preceding, almost 80 million year-long Cretaceous Period (last of the Mesozoic Era). The Silurian, third period of the Paleozoic Era, lasted only about 24 million years. The following Devonian & Carboniferous Periods were each around 60 million years.
Periods tend to end & begin with mass extinction events & eras with really big ones. The classic Big Five occurred at the Ordovician/Silurian (an ice age under ~4000 to 5000 ppm CO2 with ~96% of present solar luminosity), Devonian/Carboniferous (technically Late Devonian, as it was more drawn out than usual for MEEs), Permian/Triassic, Triassic/Jurassic & Cretaceous/Tertiary (or Paleogene) transitions. The most catastrophic P/Tr (“Great Dying”) & second or third worst K/T (or K/Pg) both ushered in new eras.
The IUGS officially defined the 42.5 million year-long Paleogene Period/System in 1991 & the 20.4 million-year Neogene in ’97. The Pg includes the Paleocene, Eocene & Oligocene Epochs, 65.5 to 23 Ma. The first two epochs continued Hothouse Cretaceous climate, featuring the warmest part of the Cenozoic, the Paleocene/Eocene Thermal Maximum. The Og (~34-23 Ma) however experienced cooling, including initiation of Antarctic glaciation, so seems more akin to the Neogene (23-2.6 Ma) & Quaternary Periods in at least this important respect.
IMO, it would have made more sense to split the Tertiary at the Eocene/Oligocene boundary, about the time that Antarctica was surrounded by the Southern Ocean, separated from South America & Australia by deep channels. The rift with South America has recently been fairly reliably dated to ~41 Ma, with a deep channel opening the Drake Passage to circumpolar circulation in the early Og now favored over a later date.
Another big Og oceanic circulatory event was the closing of the Tethys Sea (nursery of whales) by the collision of the African & Indian Plates with Asia.
Also, quoting Wiki, “The start of the Oligocene is marked by a notable extinction event called the Grande Coupure; it featured the replacement of European fauna with Asian fauna, except for the endemic rodent and marsupial families. By contrast, the Oligocene-Miocene boundary is not set at an easily identified worldwide event but rather at regional boundaries between the warmer late Oligocene and the relatively cooler Miocene.”
Transferring the Og from the Paleogene to Neogene would yield a ~32 million-year (vs. the IUGS’ ~43) Pg composed of the Paleocene & Eocene Epochs, & a ~31 million-year (vs.~20) Neogene (Oligocene, Miocene & Pliocene).
To its credit, the IUGS did a sensible thing in 2009 by lengthening the Quaternary Period & Pleistocene Epoch to include all the Quaternary glaciations (formerly awkwardly called “Pliocene-Pleistocene”). The Quaternary had started only 1.8 Ma but now begins at 2.6 Ma, not long after oceanic circulation was interrupted by the closure of the Isthmus of Panama. The Pliocene is thus a truncated Epoch, but the revision better reflects important geological & climatic change.
Of course our present Holocene is just another warm interglacial phase, but according it Epoch status is justifiable since so many megafaunal species went extinct at the Pleistocene/Holocene transition.
Again, apologies for such length on what’s basically a pet peeve.
A lot of uninformed comments all around here:
“What’s the chances of the big one hitting right on the Cretaceous /Tertiary boundary, eh?”
100 % since the end of the Cretaceous was caused by the impact. Or rather geologists defined the boundary because of the extreme biotic changes at that level.
“I have heard that it was the Dekkan traps volcano eruption that killed them.”
They may have been a contributing factor. But dinosaurs occur in the “intertrappan beds” that formed during breaks in the volcanic eruptions so the certainly weren’t immediately fatal, even for dinosaur living in India (which was an isolated island at that time).
“So what killed those dinosaurs that lived in the sea?”
Strangely enough no dinosaurs ever lived in the sea. There were other marine reptiles (mosasaurs, plesiosaurs) that became extinct at the K/T boundary though. That is not hard to explain as there was a complete ecological collapse in the ocean, probably due to phytoplankton failing to grow during the darkness immediately after the impact.
“I think the empact side of the globe should show greater signs of fires than the other side.”
“I’d like to know if the authors of this paper mapped out possible ejecta trajectories. The trajectories vary with the impact velocity and direction of course. My best guess, and it is a guess, is that very little of the ejected material was likely to make it to Australia, South and East Asia as I think that the vast majority of possible trajectories bring the material down rather quickly on the half of the planet centered on the impact site. Fires on that side? Seems quite plausible. Fires of the opposite side? Not so much I’m thinking.”
Contrariwise. This has been studied and is fairly well understood. The largest concentration of secondary impacts will actually occur near the antipodal point of the impact (this is pretty obvious if you think about trajectories a bit). An area a few thousand kilometers wide around the impact point would of course have been incinerated/boiled by a shockwave of rock vapor and superheated steam. The area least affected by secondary impacts would probably have been Antarctica.
“And why didn’t certain environmentally sensitive amphibian and reptile species die out?”
Most did, but generally speaking animals and plants in freshwater environment survived best of all. Probably because they were thermally shielded by the water and freshwater food chains are much less immediately dependent on green plants than any other.
“That was a very high relative speed event, and I didn’t see any evidence of ground structures bursting into flames. Ejecta from the Chicxulub impact that cleared the atmosphere and came crashing back would not have the same kind of relative speed, thus less chance of igniting the forests”
A high speed but very small, very brief event. Re-entering secondaries cannot have higher speed than 11 km/s and most will be in the 7-10 km/s range. The stagnation temperature for a body entering at that speed is around 3,000-4,000 degrees, which is white-hot but not quite as bright as the sun. Think a bit about the effect of a large part of the sky having a brightness temperature of 3,000-4,000 degrees for a period of hours instead of just a small spot for a few seconds.
Here is a far better paper. Written by Geologists for Geologists in the Journal of Geology.
Fireball Passes and Nothing Burns – The Role of Thermal Radiation in the K – T Event: Evidence from the Charcoal Record of North America
Geology 2003;31;1061-1064
Claire M. Belcher, Margaret E. Collinson, Arthur R. Sweet, Alan R. Hildebrand and Andrew C. Scott
Cretaceous-Tertiary event: Evidence from the charcoal record of North America
This is what I like to see, scientists challenging the accepted theory. The asteroid extinction theory is now 35 years old and it holds up well, but many aspects of it are still being challenged. That’s the practice of science I was taught decades ago.
How much of the planet’s atmosphere was blown away by the impact? There is some reason to believe that the atmosphere used to be much thicker. http://www.dinosaurtheory.com/thick_atmosphere.html Could it be that the large dinosaurs suffocated?
I have no clue whether the above conjecture is plausible. A bit of quick googling didn’t seem to produce much evidence one way or the other.
“What’s the chances of the big one hitting right on the Cretaceous /Tertiary boundary, eh?”
I knew a girl once who thought it was amazing that so many American Civil War battles, like Gettysburg, happened to get fought in National Parks.
These things can cause fire. A mountain-sized one could cause a lot of fire, no?
“Selected eyewitness reports
The Southern swamp—the epicentre of the Tunguska explosion, in 2008Testimony of S. Semenov, as recorded by Leonid Kulik’s expedition in 1930:[16]
At breakfast time I was sitting by the house at Vanavara Trading Post [65 kilometres/40 miles south of the explosion], facing north. […] I suddenly saw that directly to the north, over Onkoul’s Tunguska Road, the sky split in two and fire appeared high and wide over the forest [as Semenov showed, about 50 degrees up—expedition note]. The split in the sky grew larger, and the entire northern side was covered with fire. At that moment I became so hot that I couldn’t bear it, as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few metres. I lost my senses for a moment, but then my wife ran out and led me to the house. After that such noise came, as if rocks were falling or cannons were firing, the earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it. When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn a part of the iron lock snapped.
”
http://en.wikipedia.org/wiki/Tunguska_event
tty says:
March 27, 2013 at 8:45 am
A lot of uninformed comments all around here:
“What’s the chances of the big one hitting right on the Cretaceous /Tertiary boundary, eh?”
100 % since the end of the Cretaceous was caused by the impact. Or rather geologists defined the boundary because of the extreme biotic changes at that level.
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I’m pretty sure that part was meant as a joke.
Thanks for the rest of your informative comments.
Just 5 days ago I read this:
Few days ago I was looking at some geomagnetic anomalies across Siberia, then I looked at Google Earth and saw a spectacular feature about 9-10 km across
http://www.vukcevic.talktalk.net/SiberiaRose.htm
I am not aware of any references to it
Geologists, any ideas ?
Doug Proctor says:
March 27, 2013 at 8:20 am
No central uplift peak?
Okay, I’m fussy about the painting. It’s science. We’re supposed to be fussy.
An impact that big would send a tsunami up the Cretaceous continental sea from the Gulf of Mexico to the Arctic, one would think. I live in Alberta; out at Drumheller, you can see the Cret-Tertiary boundary in the valley wall (just above the last dark line of a coal stringer). It holds, apparently, the Iridium layer of Alvarez. However, no tsunamic debris OR (more signficantly) an erosive surface.
====================================
Doug IIRC, a structure that looks like the result of a major tsunami near the KT boundary was identified in Texas a number of years ago. If the KT boundary at Drumheller is above a coal bed, doesn’t that suggest that the land there was above sea level at the end of the Cretaceous? I’m not sure how far inland the water from even a very large tsunami will penetrate. Many tens of kilometers I should think, but maybe not many hundreds?
Everyone knows “mass extinctions” begun just as prehistoric politicians emerged from the primordial slime!
Will a fern burn with pure oxygen? Has anyone tried it? That would be the first thing to establish in postulating extinction by fire. Is it possible to burn down a palm grove? Of course a conifer forest would burn up in 30% O2. Global fire? Seems like unadulterated nonsense. For capable consideration see Wiki:
http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event
–AGF
So was it purely inelastic collision?
” wws says:
March 27, 2013 at 9:01 am
“What’s the chances of the big one hitting right on the Cretaceous /Tertiary boundary, eh?”
I knew a girl once who thought it was amazing that so many American Civil War battles, like Gettysburg, happened to get fought in National Parks.”
Isn’t like wondering why all the deer are starting to use the deer crossing areas on our highways now?
???
Is there enough oxygen in the earth’s atmosphere to support a world-wide firestorm?
Yes. Plenty.
Mass of the atmosphere 5.1*10^18 kg.
So mass of Oxygen in atmosphere is about 1.2*10^18 kg.
Biomass of Earth = 560 billion tonnes = 5.6*10^14 kg.
So there appears to be about 2000 kg of O2 for every kg of biomass. A world-wide firestorm won’t be starved by a lack of oxygen.
Question and hypothesis:
I accept the Yucatan asteroid theory.
I suggest that the entire gulf of Mexico is also an asteroid,, albeit an even older asteroid, impact zone.
Has anyone else thought this. Seems obvious to me.
Jimbo says:
March 27, 2013 at 9:17 am
Just 5 days ago I read this:
BBC 22 March 2013
Dinosaur-killing space rock ‘was a comet’
“You’d need an asteroid of about 5km diameter to contribute that much iridium and osmium. But an asteroid that size would not make a 200km-diameter crater,” said Dr Moore.
“So we said: how do we get something that has enough energy to generate that size of crater, but has much less rocky material? That brings us to comets.”
http://www.bbc.co.uk/news/science-environment-21709229
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Thanks, Jimbo. I missed that. Here’s the conference presentation:
http://www.lpi.usra.edu/meetings/lpsc2013/pdf/2431.pdf
But then, too, there’s this hypothesis from Feb:
http://phys.org/news/2013-02-group-chicxulub-crater-binary-asteroids.html
The K/T is still making waves.
Vukcevic, sounds like a good field trip.
CodeTech says:
March 27, 2013 at 6:26 am
Third, we’ve now seen the Chelyabinsk event, recorded on video from multiple angles. That was a very high relative speed event, and I didn’t see any evidence of ground structures bursting into flames. Ejecta from the Chicxulub impact that cleared the atmosphere and came crashing back would not have the same kind of relative speed, thus less chance of igniting the forests (which were probably washed away).
———-
Chenlyabinsk event was a single object. After the Chicxulub impact there would have been 10’s of millions, perhaps billions of objects re-entering the atmosphere.
If the IR was sufficient to ignite tinder, it wouldn’t have been to healthy for any animal caught out in the open at the time. First and second degree burns over the entire top side of the animal.
wsbriggs says:
March 27, 2013 at 6:49 am
The ionization radiation created from the passage of the object through the atmosphere
—
How pray tell does an object plowing through the atmosphere cause atoms to fission?
Blade says:
March 27, 2013 at 7:59 am
—
Most fires only burn a small portion of a forest or grassland. These fires would have taken out the entire forest/grassland.
Animals normally escape fires by running from them. (Plus the fact that most animals aren’t where the fires are). When the whole world is burning, where do you run to?
Jimmy Haigh. says:
March 27, 2013 at 8:01 am
—-
I read somewhere that the KT boundary layer is thickest in the southeast US and Carribean. And is thicker throughout N. America than it is in Europe and Asia.
wws and John Tillman.
You guys got it.
Paul Westhaver says:
March 27, 2013 at 9:57 am
Question and hypothesis:
I accept the Yucatan asteroid theory.
I suggest that the entire gulf of Mexico is also an asteroid,, albeit an even older asteroid, impact zone.
Has anyone else thought this. Seems obvious to me.
******************************************************************
Yes, someone has. Canadian geologist Michael Stanton thought of it two decades ago, but only published his idea in 2002. He accounts for the Permian-Triassic extinction ~250 Ma by this proposed impact, citing the Louann Salt as evidence. The hypothesis has not garnered much support. The odds of two major craterings in the same area ~185 million years apart doesn’t really enter into it.
http://www.aapg.org/explorer/2002/12dec/gom_impact.pdf
Doug Proctor says:
March 27, 2013 at 8:20 am
—
There probable was a central peak, however because of the depth of the crater, there was no solid ground underneath the peak to support it, and it sank back into the earth.
The studies I have seen put the size of the tsunami at a couple of kilometers. No way that exends more than a few hundred miles inland. Not all the way to the arctic
tty says:
March 27, 2013 at 8:45 am
“I’d like to know if the authors of this paper mapped out possible ejecta trajectories. The trajectories vary with the impact velocity and direction of course. My best guess, and it is a guess, is that very little of the ejected material was likely to make it to Australia, South and East Asia as I think that the vast majority of possible trajectories bring the material down rather quickly on the half of the planet centered on the impact site. Fires on that side? Seems quite plausible. Fires of the opposite side? Not so much I’m thinking.”
Contrariwise. This has been studied and is fairly well understood. The largest concentration of secondary impacts will actually occur near the antipodal point of the impact (this is pretty obvious if you think about trajectories a bit).
===========
Well actually, I DID think about the trajectories a bit, and I don’t think your scenario is obvious at all. To be honest, it doesn’t seem especially likely either. AFAICS, any ejecta that is travelling at less than orbital velocity (roughly 8km/sec) and most that is “launched” at angles below about 45 degrees will impact in the “impact hemisphere”. As will any material launched more or less straight up although that will presumably trail out to the West of the impact point as the Earth turns. Unless one assumes that ejecta are mostly traveling very fast and are mostly “launched” at high but not vertical angles, not all that many are coming down on the “back side”. However, I admit that I didn’t give any consideration to the distribution of ejecta velocity and elevations and assumed something sort of random — which is surely wrong. I don’t suppose you have a reference or two?
@Paul Westhaver
…I suggest that the entire gulf of Mexico is also an asteroid,, albeit an even older asteroid, impact zone…
When you come to think about it, EVERYWHERE on Earth was an impact zone at some point…
Has anyone else thought this. Seems obvious to me.
There are some suggestions that there were multiple impacts causing the KT event. Chicxulub
may or may not be the largest. There is a proposed impact structure just off the west coast of India, which may or may not be connected to the Deccan Traps event. And the argument continues as does the data gathering. Cheers –
http://www.currentscience.ac.in/Volumes/101/12/1525.pdf
http://news.nationalgeographic.com/news/2009/10/091016-asteroid-impact-india-dinosaurs.html
commieBob says:
March 27, 2013 at 8:58 am
—
It’s not even close to being plausible.
John Tillman, thank-you for the citation. You made me very happy.
When I look at the Gulf of Mexico, it looks like the superposition of an ancient double hit, then the later Yucatan hit.
The Island of Cuba appears, to me, to be impact zone ejecta, as if the asteroid hit traveling south east obliquely to the planet. The impact would push up most of Florida and leave Cuba behind in the splatter zone.
That is complete speculation on my part.
If an approaching asteroid broke apart as it approached earth, then you could get a double hit effect. Again, mere speculation on my part and I do not possess the tools or expertise to test the idea.
When I learned of Pangaea as a child and tried to fit the continents together like puzzle pieces, the Gulf of Mexico always proved to me that a piece was missing.
Thanks
Just because a feature is roughly circular is not proof that it was caused by an impact. Other evidence includes fractured crustal rocks inside the “crater”. This doesn’t exist for the Gulf of Mexico.
Neither the Chicxulub impact nor the Deccan Traps volcanism were the primary extinction mechanism at the K-T boundary.
The fact that birds were little affected discounts the impact causation. The fact that all marsupials went extinct in N. America is another bit of evidence.
However, the marsupial extinction supports the theory that surface gravity increased rapidly at the K-T interval as well as the extinction of all marine reptiles and ammonites. Dinosaurs were diminishing in numbers as well as size millions of years prior to the K-T interval.
The Gravity Theory of Mass Extinction (http://www.dinoextinct.com/page13.pdf) is the only viable theory.
@ Box of Rocks, ouch.
Ban DiHydrogen Monoxide signatory for sure.
vukcevic says:
March 27, 2013 at 9:22 am
Few days ago I was looking at some geomagnetic anomalies across Siberia, then I looked at Google Earth and saw a spectacular feature about 9-10 km across
http://www.vukcevic.talktalk.net/SiberiaRose.htm
I am not aware of any references to it
Geologists, any ideas ?
++++++++++
It’s called the Kondyor Massif.
http://earthobservatory.nasa.gov/IOTD/view.php?id=8773
I agree. Every major biological group survived, except for the dinosaurs. Other large predators such as crocodiles and sharks, survived, and the usual explanation that frogs and crocs were protected by living in an aquatic environment ignores the fact that there were wading dinos. Those discrepancies cry out as the mass extinction being the result of a biological cause, rather than a mechanical cause. Birds could survive because the disease would not reach remote islands only accessible by flying long distances, they would not survive extended global darkening and subsequent famine.
I’m always amazed at the number of people willing to say one specific thing or another “caused” the K-Pg extinctions, when it’s highly likely the blame lies in a combination of things, from the impact itself, to many major stressing events cascading from that impact. Such as the falling hot ejecta and it’s subsequent fires, yes, but also let’s throw in a massive mega-tsunami, a following cold period due to atmospheric dust, leading to loss of sunlight, causing the death of much of the plant material at the bottom of the food chain, including phytoplanton, a long period of volcanism along fault lines around the planet that were jarred into activity by the impact, and then the various ways the oceans and land then behaved on the way to “recovery” (disrupted and, or new ocean currents, “temporary” salinity changes, etc., to which the existing species of that time were not adapted. And it goes on and on.
Why shouldn’t we believe that a vastly complex set of factors is “responsible” and that one particular factor, while awesome and terrifying in it’s global scope, is nevertheless only a single slice of an even greater pie chart of awesome and terrifying effects?
Theresa says:
March 27, 2013 at 5:19 am
I have heard that it was the Dekkan traps volcano eruption that killed them. Does that create Co2 as well?
All vulcanism releases CO2 from the planet. Major volcanic episodes release major amounts of CO2. Volcanic CO2 by and large has never been part of the planetary atmosphere and is “new” in the sense that it became part of the planet during the coalesence of the planet, but never was part of the atmosphere before. Large amounts of water are also released that are “meteoric” water as well. This is water that has not been on the surface before, or not for long geological time spans. Also, when lava flows plants (and animals) burn, which also releases CO2, but that is a trivial amount compared to the volume brought up by the vulcansim.
pokerguy says:
March 27, 2013 at 6:05 am
“So what killed those dinosaurs that lived in the sea?”
Salty diet. They all got hypertension.
*
I really – REALLY – must stop having my morning coffee at my desk when reading WUWT.
This one is going on my wall. No, people, the words by Pokerguy, not my coffee (my coffee is already there).
Paul Westhaver says:
March 27, 2013 at 11:25 am
John Tillman, thank-you for the citation. You made me very happy.
When I look at the Gulf of Mexico, it looks like the superposition of an ancient double hit, then the later Yucatan hit.
The Island of Cuba appears, to me, to be impact zone ejecta, as if the asteroid hit traveling south east obliquely to the planet. The impact would push up most of Florida and leave Cuba behind in the splatter zone.
That is complete speculation on my part.
If an approaching asteroid broke apart as it approached earth, then you could get a double hit effect. Again, mere speculation on my part and I do not possess the tools or expertise to test the idea.
When I learned of Pangaea as a child and tried to fit the continents together like puzzle pieces, the Gulf of Mexico always proved to me that a piece was missing.
Thanks
*****************************************************************************************************
You’re welcome, but there are many problems with Stanton’s hypothesis. The GoM is satisfactorily explained by plate tectonics.
Staten-John says:
March 27, 2013 at 11:37 am
Neither the Chicxulub impact nor the Deccan Traps volcanism were the primary extinction mechanism at the K-T boundary.
The fact that birds were little affected discounts the impact causation. The fact that all marsupials went extinct in N. America is another bit of evidence.
However, the marsupial extinction supports the theory that surface gravity increased rapidly at the K-T interval as well as the extinction of all marine reptiles and ammonites. Dinosaurs were diminishing in numbers as well as size millions of years prior to the K-T interval.
The Gravity Theory of Mass Extinction (http://www.dinoextinct.com/page13.pdf) is the only viable theory.
****************************************************************************************************************
It is so far from the only viable “theory” that it’s about as invalid as possible, IMO.
Nor is it a “fact” that birds were little affected. They were almost all wiped out.
Nothing about marsupial survival or extirpation suggests an increase in gravity, but is well explained by bolide collision at the K/T in the Yucatan.
Sorry, but no credible evidence supports this notion. By contrast, abundant evidence from many separate lines of inquiry support a role, arguably predominant, for the impact. The formation of the Deccan Traps as the Indian Plate passed over the Reunion Hotspot may not have helped.
vukcevic says:
March 27, 2013 at 9:22 am
Few days ago I was looking at some geomagnetic anomalies across Siberia, then I looked at Google Earth and saw a spectacular feature about 9-10 km across
http://www.vukcevic.talktalk.net/SiberiaRose.htm
I am not aware of any references to it
Geologists, any ideas ?
******************************************************
Just looking at the picture, my WAG is that looks like a volcanic eruption with a lava flow that came out to the bottom left.
Staten-John says:
March 27, 2013 at 11:37 am
—
If gravitational changes killed the Dinos, how did the birds survive? Presumably a big increase in gravity would have rendered them unable to fly.
BTW, changes in gravity would not have any impact on sea level.
Every time I see a documentary or read an article about this, some major detail changes. Large animals were already dying. Large animals died because of cold. Large animals died because of fire. Large animals didn’t die until several thousand years later. Large animals died because of disease. Large animals died because oxygen percentages decreased. Large animals were kidnapped by aliens. Large animals went out for a pack of cigarettes and never came back.
Of course, the first lesson here is to not trust documentaries and articles, which are primarily speculative (speculative means “made up”).
Luckily we’re not currently facing the choice of whether or not to allow a large asteroid to strike Earth, so I can shelve the subject for the moment.
MarkW,
Birds were able to avoid extinction for several reasons:
1. They were able to adapt to changing surface gravity better than mammals because they did not give live birth. This is contrast to marsupials which went extinct in N. America.
2. They could evolve changes, wing area to mass ratio, etc.
3. They were able to nest in high places making them less vulnerable to predation, just as they do today.
Note that the change in surface gravity took place over tens of thousands of years, not instantaneously.
Sea level would definitely be affected by changes in surface gravity. If you read the theory, shifting of the cores away from Earth-centricity would have lowered surface gravity in one hemisphere (i.e., on Pangea) and raised it on the other hemisphere (i.e., antipodal to Pangea).
This is confirmed, see Wiki Sea level chart.
Summary of evidence for the Yucatan impact as main if not sole cause of the K/T MEE:
http://www.sciencemag.org/content/327/5970/1214.abstract
Granted, this looks a lot like consensus science, but the authors IMO do a good job of addressing the arguments & evidence of Chicxu-skeptics like Keller. They consider issues of timing, the case for gradual decline in species diversity, climate change, the Deccan Traps & for multiple impacts, among other alternative hypotheses.
It’s pay-walled, but various articles from 2010 describe its conclusions & methods.
For the effect on birds of the K/T, please read this:
Longrich, N. R., T. T. Tokaryk, et al. (2011). “Mass extinction of birds at the Cretaceous-Paleogene (K-Pg) boundary.” Proceedings of the National Academy of Sciences 108(37): 15253-15257.
Enantiornithes are the “opposite birds”, which were dominant in the Cretaceous, but apparently totally wiped out in the MEE, along with all others except a few modern groups.
Theresa says:
March 27, 2013 at 5:19 am
“I have heard that it was the Dekkan traps volcano eruption that killed them. Does that create Co2 as well?”
It was like this. The Chixulub impact sent shock waves to the opposite side of the earth, which started the Dekkan traps volcanism, which caused the extinction. Dust loading of the stratosphere from extended volcanism is imho the most likely candidate.
We know peat fires can last for decades when large peat bogs slowly dry out.
And IMO this is what happened at the KT Boundary. Large amounts of debris in the atmosphere, solar insolation greatly reduced, and consequently ocean evaporation and precipitation reduced. Peat bogs start to dry out, and fires started by whatever means take hold. Then the smoke from the fires continues the reduced insolation/evaporation/precipitation regime over decades. And if very large peat bogs exist, centuries, even millenia of the peat fires/smoke/reduced precipitation regime seems possible.
The word Probably means nothing. It is like the word Height. The building had a height. The event probably occurred. These are sentences which convey no information. How how was the building? How probable was the event?
Could, would, maybe, probably, might, may. These are all words in any story which tell you that somebody is plucking something out of their ass.
“””””…..AleaJactaEst says:
March 27, 2013 at 5:21 am
Interestingly the only geologist on the paper was the third author. The KT boundary discussion (now I’m showing my age as I prefer the KT monika) is many years old. …….”””””
I’m under the impression that the fossil records show the die off starting long before any impact, and coninuing for eons after the impact. I thought the rise of mammals played a role.
The birds that became extinct at the K-T boundary, or before, were known as archaic birds. Some had teeth and probably had other characteristics which were disadvantages when surface gravity increased. Not a lot is known about them.
DaveF says:
March 27, 2013 at 5:46 am
So what killed those dinosaurs that lived in the sea?
==============================================================
It must have been ………..
The speck on the flea on the tail on the frog on the bump on the log in the hole in the bottom of the sea
“I’ll get my coat” (sorry)
Since the AGW fanatics are now accusing us skeptics of causing the Medieval Warm Period, maybe we dunnit.
What about the Shiva impact site? Is it not a bit larger than Chicxulub?
The Russians always have such cool names. Where we in the US get the incorrectly named “Meteor Crater” near Winslow, AZ.
“Abstract
For several hours following the Chicxulub impact, the entire Earth was bathed with intense infrared radiation from ballistically reentering ejecta. The global heat pulse would have killed unsheltered organisms directly and ignited fires at places where adequate fuel was available. Sheltering underground, within natural cavities, or in water would have been a necessary but not always sufficient condition for survival. Survival through sheltering from an initial thermal pulse is not adequately considered in literature about Cretaceous- Tertiary nonmarine extinctions. We compare predicted intense, short-term, thermal effects with what is known about the fossil record of nonmarine vertebrates and suggest that paleontological evidence of survival is compatible with theoretical results from bolide physics.”
http://gsabulletin.gsapubs.org/content/116/5-6/760.short
Re Vukevic query.
The feature you mentioned is referred to as the Gora Konder crater.
Possibly an impact site but there doesn’t seem to be a lot known about it.
Also some suggestion that it hosts a platinum mining operation
http://below-topsecret.livejournal.com/770802.html
A possibility……Pt deposits are known to have formed at other impact sites
It would have to quite young as it seems well preserved, possibly about the same age as Meteor Crater in Arizona but that’s just a guess.
Whoops, apology. That should be Vukcevic
More Re Vukcevic query
Apparently not a meteorite crater at all. Rather an igneous intrusion.
And not young, but only youngish at around 112Ma
http://www.atlasobscura.com/places/kondyor-massif
http://earthobservatory.nasa.gov/IOTD/view.php?id=8773
http://link.springer.com/article/10.1134%2FS0869591112060033#page-1
CF my earlier comments and changing opinions to fit facts
DaveF says:
March 27, 2013 at 5:46 am
So what killed those dinosaurs that lived in the sea?
###
You have just hurt Nessy’s feelings 🙁
“””””…..jim2 says:
March 27, 2013 at 7:36 pm
“Abstract
For several hours following the Chicxulub impact, the entire Earth was bathed with intense infrared radiation from ballistically reentering ejecta…….”””””
So the orbital period at earth surface is 84 minutes. So how does that “ejecta” re-entry shower last “several hours” ?
Enquiring minds want to know.
John Tillman says:
March 27, 2013 at 8:41 am
###
I was pretty happy that the Gelasian had been moved to the Pleistocene. I had not thought about the position of the Oligocene, but what you opined makes a lot of sense. I tend to think of things in terms of Eocene and post Eocene. It would surely make it easier for me to explain what my interests are which is currently the Oligocene of the Paleogene, the Neogene, and the Quaternary.
In response to: MarkW March 27, 2013 at 10:49 am who responded to wsbriggs March 27, 2013 at 6:49 am . Briggs: “The ionization radiation created from the passage of the object through the atmosphere” – Mark W: “How pray tell does an object plowing through the atmosphere cause atoms to fission?”
__________
How do you get “fission” from Briggs’ statement? Ionization is the stripping of one or more electrons from an atom. As energy is added to an atom, the electrons get more energy (excitation) and if enough energy is gained an electron can escape from the atom (ionization). At some point in both excitation and ionization, the gained (excess) energy will be released. In excitation, the energy is released either by the emission of electromagnetic energy or by transfer to another atom. In ionization, much of the excess energy will be imparted to the escaping electron but usually there is also an emission of electromagnetic radiation. One means of Imparting excess energy into an object’s atoms can be accomplished via frictional forces such as experienced by an object coming from space and entering our atmosphere. If I am following the argument correctly on this thread, then the impact of a large meteor, asteroid or comet would throw material (ejecta) high enough back into the atmosphere to produce further objects subject to frictional heating and which in turn would produce excited/ionized molecules, which in turn would emit harmful electromagnetic radiation (principally IR). The ejecta phenomena would be a one time event, but could (I have no idea) be wide spread. Atom –> add energy —> excitation and/or ionization —> production of electromagnetic radiation (light, IR, radio waves, et cetera) —-> too much bad radiation = dead things.
george e. smith, the ejecta from a major impact comes out at a wide ranges of velocities, from slow to fast, from low to high angles but mostly around 45 degrees. Some is even at greater than escape velocity (thus the few Mars rocks that have been found on Earth). Many pieces will go very high, taking a long time to fall back, with stragglers tailing off over hours, days, even weeks- consider a chunk thrown as far as the moon, but still on an elliptical path that eventually hits the earth again.
A video showing the ejecta from a 2 km/s impact:
A simulation of part of the ejecta from a large impact. The Earth rotates while the crud flies high.
Re: ‘Siberia Rose’
Thank you for all of the comments and links, I did eventualy find some myself. As much as its visual and the geological aspects are remarkable, they are more than matched by its geomagnetic anomaly, I will post some details at a later stage.
Thanks again.
sorry, forgot link to the most recent article:
http://link.springer.com/article/10.1134/S1028334X12080053#page-1
I strongly recommend Richard Muller’s book, ‘Nemesis’. He was closely involved with the Alvarez group which discovered the cause of the death of the dinosaurs. The book tells the story of that discovery and it is a fantastic read, showing science at its best. It was written long before Muller was tainted by the AGW nonsense.
Nemesis refers to his theory that he described towards the end of the book: that comet/asteroid impacts that cause extinctions occur regularly, and are due to a distant companion of the sun. That companion has never been discovered and I assume his Nemesis theory is long dead. His cherished AGW theory also seems to be dying….
Chris
Well actually, I DID think about the trajectories a bit, and I don’t think your scenario is obvious at all. To be honest, it doesn’t seem especially likely either. AFAICS, any ejecta that is travelling at less than orbital velocity (roughly 8km/sec) and most that is “launched” at angles below about 45 degrees will impact in the “impact hemisphere”. As will any material launched more or less straight up although that will presumably trail out to the West of the impact point as the Earth turns. Unless one assumes that ejecta are mostly traveling very fast and are mostly “launched” at high but not vertical angles, not all that many are coming down on the “back side”. However, I admit that I didn’t give any consideration to the distribution of ejecta velocity and elevations and assumed something sort of random — which is surely wrong. I don’t suppose you have a reference or two?
Actually only debris ejected at a fairly high angle through the “hole” in the atmosphere caused by the entry can get very far. The stuff ejected at low angles is braked by air resistance within several hundred kilometers.
The best reference on the subject is here:
http://onlinelibrary.wiley.com/doi/10.1029/2001JE001532/abstract
Unfortunately it does not seem to be available outside the paywall. However here is a animation showing the calculated impact distribution:
http://www.lpi.usra.edu/science/kring/epo_web/news/chicxulub2.html
“So the orbital period at earth surface is 84 minutes. So how does that “ejecta” re-entry shower last “several hours” ?
Enquiring minds want to know.”
Because most of the re-entering ejecta was ejected at high angles into very excentric elliptic trajectories which only re-enters the Earths atmosphere several hours later. As a matter of fact a fair amount probably went into orbits around the Sun. I would expect that there was a lot of shooting stars for centuries afterwards as the Earth swept up most of the debris.
Luther Wu says:
March 27, 2013 at 6:04 am
No, it’s survivor guilt. And I’m voting to keep KT. Like I vote to keep Pluto. Oh, crap, does that mean a meteor is heading for this neo dinosaur?
tty says:
March 28, 2013 at 4:29 am
“Actually only debris ejected at a fairly high angle through the “hole” in the atmosphere caused by the entry can get very far. …”
Thanks for the response. I think I understand what you’re saying, but I still don’t find the analysis to be overwhelmingly convincing. e.g. I think you (and “they”?) are asuming that the “hole in the atmosphere is vertically above the impact point. But isn’t a lower angle impact creating a low angle directional “tunnel” a lot more likely? etc, etc, etc. (OTOH material that is fairly large and travelling really fast can presumably “punch” its way out vertically or near vertically whereas lower angle material is going to need to be larger and/or faster to get a long distance “downrange”)
I did google the Chixulub impact angle and found some modeling, but no consensus
Anyway, I don’t propose to spend the next six months/years worrying about this.
Thanks Jimmy Haig!
(What is the chances of the big one hitting….)
I just sprayed coffee all over the keyboard and monitor!
But I am a bit dissapointed that not too many tried to correct you. That would have made for more fun morning reading.
“So what killed those dinosaurs that lived in the sea?”…Thanks to all those those who replied to my query, humorously or otherwise. Good comments, DaveF.
Staten-John says:
March 27, 2013 at 3:17 pm
The birds that became extinct at the K-T boundary, or before, were known as archaic birds. Some had teeth and probably had other characteristics which were disadvantages when surface gravity increased. Not a lot is known about them.
**********************************************************************************************************************
A remarkable amount is known about Cretaceous birds, due in large part to the wonderful EK Lagerstätten of China but also other epochs & regions, such as LK western North America, especially for sea birds. Your hypothesis is falsified by the many non-archaic birds wiped out at the K/T along with their archaic kin. It wasn’t the presence of teeth & claws that determined which avian species survived, but their lifestyles & locales. Those few modern groups which came through the catastrophe lived far from the worst effects of the impact & had feeding behavior that allowed them to live into the post-apocalyptic Cenozoic.
Here you can read up on archaic birds:
http://en.wikipedia.org/wiki/Enantiornithes
And here on Cretaceous birds of modern aspect, with a cutting-edge cladogram:
http://en.wikipedia.org/wiki/Euornithes
___________________________________________________________________________
DesertYote says:
March 27, 2013 at 10:33 pm
John Tillman says:
March 27, 2013 at 8:41 am
###
I was pretty happy that the Gelasian had been moved to the Pleistocene. I had not thought about the position of the Oligocene, but what you opined makes a lot of sense. I tend to think of things in terms of Eocene and post Eocene. It would surely make it easier for me to explain what my interests are which is currently the Oligocene of the Paleogene, the Neogene, and the Quaternary.
**********************************************************************************************************************
Thanks. I would be happy with a still on-going geologic period coincident with your interests, ie a revised Neogene including the Og on one end & the Quaternary on the other. There is not much left of the Pliocene sans Gelasian, but the Miocene is already so long that attaching it at the end of that epoch doesn’t help. If you have pull with the IUGS, please see what you & your colleagues can do about this. The Gelasian move shows there’s hope for more rational geotime ordering.
@TomR,Worc,MA
The sea-going reptiles, not dinosaurs, were wiped out at the K-T interval because an increase in surface gravity would increase water pressure at all depths because water pressure is dependent on depth, water density and “g” (i.e. magnitude of gravity).
Reptiles must frequently come to the surface to breathe, therefore, all vertical movement in the water column would be problematic for reptiles and also ammonites, which also became extinct at this time.
@John Tillman,
Not enough is known about the archaic birds to explain why they went extinct and the other group did not including their internal structure.
However, the fact that the birds that did not become extinct at the time of the asteroid impact casts doubt on the severity of the effects of the impact. One would expect birds to be much more susceptible to the alleged environmental effects such as the blistering heat, cold, smoke, lack of food, etc. which would affect the highly active birds.
The above could also be applied to lizards, snakes and other environmentally sensitive species casting further doubt on the impact extinction hypothesis.
Staten-John says:
March 27, 2013 at 1:12 pm
—
Mammals didn’t die out. Dinosaurs did.
Dinosaurs also lay eggs.
The change happened slowley enough that birds could adapt, but no other animals could?
Anyone who thinks that it is possible for the core to shift sufficiently to change gravity a noticeable amount between hemispheres is not thinking clearly. (And that’s being charitable.)
Leg says:
March 27, 2013 at 11:56 pm
—
Now you have to get those low energy electrons from their position miles up, down to the surface with enough energy to do something more than cause a static build up.
Staten-John says:
March 28, 2013 at 10:10 am
—-
An increase in gravity would have no impact on the ability of creatures to move through water.
Drag is determined by density, and density of water does not increase with gravity.
On the other hand, gravity does increase the density of air, which would make it much more difficult to fly. Hence birds would be the first to die as they would have trouble getting into the air, and more difficulty staying there if they did succeed in getting launced.
BTW, even if the core did manage to shift, it would only increase the gravity in one hemisphere compared to the other by at most a few percent. Not enough to impact life.
Staten-John says:
March 28, 2013 at 10:10 am
@TomR,Worc,MA
The sea-going reptiles, not dinosaurs, were wiped out at the K-T interval because an increase in surface gravity would increase water pressure at all depths because water pressure is dependent on depth, water density and “g” (i.e. magnitude of gravity).
Reptiles must frequently come to the surface to breathe, therefore, all vertical movement in the water column would be problematic for reptiles and also ammonites, which also became extinct at this time.
************************************************************************************************************************
How then do you explain the survival of freshwater & marine reptiles like sea snakes & turtles, tuatara ancestors, crocodilians & their relatives?
__________________________________________________________________________
Staten-John says:
March 28, 2013 at 10:24 am
@John Tillman,
Not enough is known about the archaic birds to explain why they went extinct and the other group did not including their internal structure.
However, the fact that the birds that did not become extinct at the time of the asteroid impact casts doubt on the severity of the effects of the impact. One would expect birds to be much more susceptible to the alleged environmental effects such as the blistering heat, cold, smoke, lack of food, etc. which would affect the highly active birds.
The above could also be applied to lizards, snakes and other environmentally sensitive species casting further doubt on the impact extinction hypothesis.
**************************************************************************************************************
It’s clear that you don’t know enough about the opposite birds & their modern relatives to explain their extinction, but ornithologists & paleontologists have good explanations, which have been tested in the fossil & not yet falsified. Vaguely imagining internal structure explanations is not science. Make a falsifiable hypothesis.
Certain types of modern (& possibly one opposite bird line) did indeed have what it took to survive, & had you bothered actually to read the scientific literature, or even Wiki, you’d know what those ways of living were.
The impact extinction hypothesis has by now achieved theory status, since the hypothesis has been rigorously tested under decades of attack by skeptics, God bless them (welcome & encouraged in real science) & not yet been falsified, least of all by an easily shown false gravity change hypothesis, if I may dignify the baseless, WA speculation with that term.
@johnTillman,
Don’t keep it a secret, tell us what those ways of living were. Just a few bullet points would suffice.
@MarkW
I’ll try to address your multiple posts:
“Mammals didn’t die out. Dinosaurs did.
Dinosaurs also lay eggs.”
1. Yes the above is true. However, the mammals were extremely small compared to ost dinosaurs. The smallest dinosaurs might have survived if mammal predation, of the dinosaur’s eggs, didn’t happen.
“The change happened slowley enough that birds could adapt, but no other animals could?”
2. My answer to the first question applies here. Birds were able to avoid mammal predation of their eggs and themselves because they could “hide” in treetops and on cliffs.
“Anyone who thinks that it is possible for the core to shift sufficiently to change gravity a noticeable amount between hemispheres is not thinking clearly. (And that’s being charitable.)”
3. This opinion has no scientific basis.
“An increase in gravity would have no impact on the ability of creatures to move through water.
Drag is determined by density, and density of water does not increase with gravity.”
4. Please reread my earlier post. Water pressure is directly proportional to “g” (gravitational strength). Any creature (including all sea-going reptiles) must move vertically in the water column to get to the surface to breathe. Vertical movement is hampered by an increase in water pressure per unit depth.
“On the other hand, gravity does increase the density of air, which would make it much more difficult to fly. Hence birds would be the first to die as they would have trouble getting into the air, and more difficulty staying there if they did succeed in getting launced.”
5. The increased air pressure would be insignificant compared to that of water. And, as pointed out earlier, birds has tens of thousand of years to evolve flight compensation for differences in air pressure.
“BTW, even if the core did manage to shift, it would only increase the gravity in one hemisphere compared to the other by at most a few percent. Not enough to impact life.”
6. If you reread the theory you will understand this concept. The amount of core shift is directly determined by the size of the mass that moves latitudinally and the distance it moved. That mass was all of Pangea.
@John Tillman
“How then do you explain the survival of freshwater & marine reptiles like sea snakes & turtles, tuatara ancestors, crocodilians & their relatives?”
1. See my response to MarkW about water pressure increasing per unit depth with an increase in surface gravity. Freshwater depth is insignificant compared to that of sea-going fauna. Most of those you mentioned can live in a few feet of water.
Staten-John says:
March 28, 2013 at 1:36 pm
@johnTillman,
Don’t keep it a secret, tell us what those ways of living were. Just a few bullet points would suffice.
**************************************************************************************************************************
Would it kill you to Google “k/t extinction birds”? Or to read the links I posted?
Contrary to your unresearched assertion, birds were, as I replied, almost wiped out at the K/T. All birds except some neornitheans became extinct (although one non-neornithine, Qinornis paleocenica, has been claimed to show up in the Cenozoic). Groups thriving right up to the impact (or within about 300K years, which is current resolution ability), like the opposite birds (enantiornithines) & flightless hesperornithiform divers, suddenly disappear from practically all ecological niches on all continents & seas.
That lots of opposite bird fossils have been found from the latest Maastrichtian Age supports their mass extinction from effects of the Chicxulub impact. Very few Cretaceous bird species, genera, families & orders survived the hit. Cretaceous ancestors of modern bird lineages like waterfowl, barnyard fowl & ratites did survive, since assignable remains of these basal groups have been found in the Paleogene Period. However to date just a single bird species, in the US & Canadian West, has been with some confidence dated from both above & below the K/T boundary:
http://www.pnas.org/content/108/37/15253
A putative waterfowl has been claimed for Cretaceous Antarctica, & another from Texas.
The paper linked below suggests that neornithine birds may have survived the extinction thanks to their ability to dive, swim or shelter in aquatic & marshy habitats. Many neornithine species burrow, nest in holes in trees (which did not all burn up) or termite mounds, which refugia could have protected them from catastrophic effects of the K/T strike. Their descendents not only survived but thrived during the Paleogene by filling ecological niches vacated by extinct non-avian dinosaurs. This includes the top predator niche in some environments.
http://www.ugcs.caltech.edu/~presto/cenozoic.pdf
___________________________________________________________________________
Staten-John says:
March 28, 2013 at 2:12 pm
@John Tillman
“How then do you explain the survival of freshwater & marine reptiles like sea snakes & turtles, tuatara ancestors, crocodilians & their relatives?”
1. See my response to MarkW about water pressure increasing per unit depth with an increase in surface gravity. Freshwater depth is insignificant compared to that of sea-going fauna. Most of those you mentioned can live in a few feet of water.
*******************************************************************************************************************
How deep do you suppose that mosasaurs & plesiosaurs hunted?
Some plesiosaurs may have been bottom feeders. They’ve been discovered with belemnite & ammonite fossils apparently in their stomachs. Their jaws were probably powerful enough to bite through the hard internal skeletons or shells of such prey. They may also have eaten bony fish inhabiting shallow waters.
Mosasaurs of course ate plesiosaurs. Did you really imagine that the epicontinental Seas of Kansas, for instance, were abysmal in their profundity? (There’s a great maritime Mesozoic Web site by that name. I’d urge you to visit it & learn before speculating wildly.)
PS: Hesperornis kin didn’t survive while wholly beaked divers might have not because the former had teeth, but more probably because of their lack of mobility on land & dependence on habitats severely hit by the effects of the Yucatan impact.
“””””……tty says:
March 28, 2013 at 4:41 am
“So the orbital period at earth surface is 84 minutes. So how does that “ejecta” re-entry shower last “several hours” ?
Enquiring minds want to know.”
Because most of the re-entering ejecta was ejected at high angles into very excentric elliptic trajectories which only re-enters the Earths atmosphere several hours later. As a matter of fact a fair amount probably went into orbits around the Sun. I would expect that there was a lot of shooting stars for centuries afterwards as the Earth swept up most of the debris……”””””
Well I understand how ballistic trajectories work. An ejected particle, will never have more energy, than at the instant it is blasted from the ground, and at the time of highest kinetic energy, it also is in the densest atmosphere, and therefore losing energy due to radiation and the friction that heats it.
It will exit earth’s atmosphere (if high trajectory) with much lower energy than it had on launch, and it will arrive back at earth upper atmosphere at no more than that energy.
So any intense infrared radiation is going to be concentrated in the first few seconds of the ejection phase, since the maximum amount of ejected material with the highest energy, is present at that time.Simple randomness, will spread the objects into a broad spectrum of orbits, so the returning material (only part of it returns) arrives spread out in time, and reduced in energy from what launched from the ground.
I see no way, the returning material can create as much thermal havoc as the ejected material made in just a few seconds. And as for some material going into sun orbit; where else could it possibly go.
And I would doubt that much of that material is ever encountered again by earth on later trips around the sun.
And returning material will be in the atmosphere for a few seconds at most. I simply don’t buy a rain of infrared cooking for hours.
PPS: I went to the Oceans of Kansas site (not Seas; I shouldn’t rely on memory at my age) to learn more myself about mosasaurs & found this info relevant to their salinity & depth preferences:
“Mosasaurs ruled the oceans of the Late Cretaceous and were beginning to invade fresh water environments such as estuaries, swamps and rivers when the Age of Dinosaurs ended.”
Not a member of the snake-lizard clade I’d want swimming up any river near me. Thank God for the bolide impact. Creative destruction for mammals.
“””””…..Doug Jones says:
March 28, 2013 at 12:19 am
george e. smith, the ejecta from a major impact comes out at a wide ranges of velocities, from slow to fast, from low to high angles but mostly around 45 degrees…..”””””
So what is the mechanism that focusses the ejecta into trajectories around 45 degrees. Certainly the longest ranging paths, at any launch velocity, would ocur around 45 dgree launch angle. But what causes more objects to choose that launch angle ? How is that process modulated by the original object impact angle ?
“When the charcoal data are corrected for the known changes in sedimentation rates, they exhibit an excess of charcoal, not a deficiency.”
There’s not enough charcoal in the sample, so rejigger the sedimentation rate data and tada! there’s excess charcoal in the sample. Nevermind the amounts of charcoal or anything else in the sample hasn’t actually changed.
To quote Adam Savage “I reject your reality and substitute my own!”
If X amount of sediment containing C amount of charcoal was deposited in T amount of time, that’s how much charcoal there is. “Correcting” the sedimentation rate to what’s observed from some other sample is simply bad science, heck that’s not science at all. One can *compare* data from different samples to get a *contrast* between them, but one cannot take some measurement from one sample, apply it to another sample and claim “The data supports my theory.”.
It’s the same sort of “science” as claiming that two monitoring sites in Australia, at two different altitudes and different distances from the coast, are measuring the same temperature because one came after the other in time and was assigned the same designation when the preceding one was decommissioned.
Even without assuming IR radiation-ignited global fires, with consequent increased atmospheric CO2, other effects of the impact(s) can account for observed extinctions.
Among these are: 1) megatsunamis, 2) inhibition of photosynthesis from lofted dust & sulfuric acid aerosols (the bolide struck gypsum deposits, producing SO2, precursor of sulfuric acid) & 3) acid rain (but not enough to kill off all amphibians).
http://www.sciencemag.org/content/327/5970/1214
The lower level of O2 detected in the early Paleocene does however suggest at least regional firestorms.
The climate was changing at the end of the Cretaceous, as it always does. The oceans were regressing, perhaps due to less undersea volcanism. The Deccan Traps were spreading over the Indian Plate due to surface volcanism.
But the climate was still in Hothouse mode, where it remained until global cooling set in from the mid-Eocene, ~49 Ma (attributed by some at least in part to the Arctic Azolla Event). IMO it’s therefore likely that dinosaurs & other archosaurs would have continued to dominate the land & other diapsid reptiles the seas for at least another 16 million years absent the Yucatan impact. Indeed, mammals still didn’t become dominant until well into the Cenozoic Era, with birds & snakes ruling many terrestrial & marine environments in the Paleogene Period. For that matter, terror birds (They eat horses, don’t they?) ruled the roost in South America even in the Neogene, until the Isthmus of Panama connected that then-island continent with North America in the Pliocene Epoch. Indeed birds dominated New Zealand & some other oceanic islands until the Holocene arrival of humans, & giant varanid lizards (goannas) remained among the top predators of Australia.
Staten-John says:
March 28, 2013 at 10:10 am
@TomR,Worc,MA
The sea-going reptiles, not dinosaurs, were wiped out at the K-T interval because an increase in surface gravity
Dear John, before any discussion about an increase in gravity, please try to run the numbers and check what variations in gravity would be achieved through continental drifts.
The theory that was posted by you above does not show any numbers, it just states that a variation change occurred. But the variations that the theory talks about are minimal, as the continental crust is only tens of kilometers in comparison with 6000+ kilometers of the Earth radius.
Please try to use Newtons law and look at the numbers that you get. A very high level approximation should be enough to give an idea.
https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation
Of course even now we can see gravitational differences between areas, for instance as undersea volcanoes achieve to raise the sea level above them by a couple of meters through their mass.
Even greater differences are between the equator and the poles, as the earth is rotating and this creates a difference which is much above what one can achieve with continental drift:
https://en.wikipedia.org/wiki/Gravity_of_Earth
“In combination, the equatorial bulge and the effects of the Earth’s inertia mean that sea-level gravitational acceleration increases from about 9.780 m·s−2 at the Equator to about 9.832 m·s−2 at the poles, so an object will weigh about 0.5% more at the poles than at the Equator.[3][4]”
But no extinction is happening because of this for any birds flying from the cold to warmer areas or humans travelling…
@LarsP
Don’t be offended by my response because most people don’t understand the Law of Conservation of Angular Momentum (LCAM). An explanation can be found on Wikipedia.
As I have explained in many forums, the change in surface gravity is the result of Pangea’s center of mass moving well north and south of the equator. If you reads the link to the summary I posted previously, you will find scientific verification of this movement.
If you understand LCAM, you would know that Pangea’s north or south movement would alter the Earth’s AM unless one of two things happened:
1. The Earth’s rotational speed changed
OR
2. The core elements moved to away from centricity.
The first option did not happen, leaving the second option.
The mass of Pangea is small compared to that of the Earth, however it is not this mass alone that is significant. It is the mass times the distance of the mass from the rotational axis SQUARED, that is significant. This number is very large. Review moment of inertia also.
@John Tillman
“The paper linked below suggests that neornithine birds may have survived the extinction thanks to their ability to dive, swim or shelter in aquatic & marshy habitats.”
If this were a viable explanation then some seagoing reptiles would have survived, yet not a single one of the them, large or small, survived.
My belief, since no one seems to have a logical explanation, is that the neornithine birds were better suited to survive increasing surface gravity which occurred over tens of thousands of years.
Perhaps the archaic birds that became extinct were primarily gliders, not capable of full powered flight.
This recent paper shows that mosasaurs invaded freshwater environments remarkably early in their history. From what I read at Oceans of Kansas, I got the idea that perhaps this happened only in the Maastrichtian Age (end Cretaceous, 72.1-65.5 Ma), but they’ve been found in a Hungarian freshwater site from way back in the Santonian (85.3–83.5 Ma):
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051781
During the Maastrichtian, a pronounced marine regression occurred, so that the northern half of the Western Interior Seaway on North America dried out & the remaining southern portion narrowed, making abundant coastal plain habitat for such familiar & strange dinosaur characters as, among theropods, carnivore T. rex, possibly omnivorous Troodon & Ornithomimus, giant herbivore Therizinosaurus, birds, including the maritime Hesperornis; the enormous sauropod Alamosaurus; plant-eating ornithischians Triceratops, Ankylosaurus, Pachycephalosaurus & a variety of hadrosaurs. So I thought maybe the receding seas accounted for mosasaurs invading fresh & brackish waters, but apparently these aquatic environments had been attracting them for over ten million years by the Maastrichtian. Clearly, at least some of them liked shoals.
Why not stop making easily disproved, uneducated assertions & actually do some research & thinking before typing. The archaic birds were most certainly capable of powered flight. They had asymmetric flight feathers, keeled sterna (meaning breast meat due to big flight muscles) & pygostyles (“parson’s noses”) sprouting tail feathers for precise control of aerial maneu, just like modern birds. Opposite birds were such good fliers that they out-competed all the smaller pterosaurs, which had gone extinct before the impact, leaving only a few gigantic flying reptiles to be wiped out by it. Until you got close enough to see their tiny teeth & claws, they would have looked like modern birds. Hoatzins still have claws.
I’ve already pointed out to you that not all marine reptiles went extinct. Your lame, made-up excuse that mosasaurs & plesiosaurs must have inhabited deeper water than sea snakes & sea turtles has already been shown false. As I’ve indicated, mosasaurs even invaded rivers, swamps & estuaries, so some lived in waters no deeper than crocodilians, of which there were in any case marine species in the Cretaceous. The marine habitats of plesiosaurs & mosasaurs were primarily shallow epeiric seas or the continental shelves of oceans.
Giant sea snakes replaced their mosasaur kin as marine predators in the Paleocene Epoch.
By the K/T boundary 65.5 Ma, archaic birds had been adept powered fliers for more time than has passed since the extinction then. As long as 80 million years is possible, ie since the Jurassic/Cretaceous boundary:
http://en.wikipedia.org/wiki/Pygostylia
Even Archeopteryx, from the Late Jurassic some 90 million years before the K/T, was able to fly, although it lacked a keeled sternum & had a long tail like most theropods instead of a pygostyle. Paleontologists are coming to regard Archie as a flying dromeosaurid (Velociraptor kin) rather than a “bird”. There were other flying maniraptoran dinosaurs in the Early Cretaceous, trying out different systems, like the four-winged Microraptor. So by the K/T, opposite & modern birds & those in between had millions of years of strongly powered flight behind them.
Staten-John says:
March 29, 2013 at 12:18 pm
@LarsP
Don’t be offended by my response because most people don’t understand the Law of Conservation of Angular Momentum (LCAM). An explanation can be found on Wikipedia.
…..
The mass of Pangea is small compared to that of the Earth, however it is not this mass alone that is significant. It is the mass times the distance of the mass from the rotational axis SQUARED, that is significant. This number is very large. Review moment of inertia also.
I am not offended. I have been called denier and worst, I do not get easily offended, I learned that mostly people do project their own misunderstandings on others.
So please John, try to do the math and run the numbers. There is no use to continue the discussion without showing a calculation.
@John Tillman,
“The archaic birds were most certainly capable of powered flight.”
Where is your proof of this statement? You’re only giving your opinion. Also, the presence of claws indicates that they most likely did a lot of tree climbing, not something a bird capable of ordinary flight would have, but gliders would have.
All seagoing reptiles went extinct, contradicting what you wrote.
The Western seaway was gone before the asteroid impact due to the massive regression, therefore, your comments about the mosasaurs occupying shallow waters at the K-T transition is unfounded. Also, you don’t know if the mosasaurs that entered shallower waters had to return to deeper waters to reproduce. Again, a lot of this is just your opinion.
Staten-John:
I gave provided convincing evidence that archaic birds were excellent fliers. No use replying to you if you ignore all I say & refuse to read links I provide or do any actual research on your own. Not to mention flat out lying about what I said re. sea-going reptiles.
Archaic birds, just like modern birds, had brains adapted for flight control, asymmetric flight feathers, a keeled breastbone with large muscles for wing flapping & tail vertebrae fused into a pygostyle to which was attached tail feathers to provide more lift & to make the same kind of fine control movements as in modern birds. These are observable facts, not my opinion.
Again, opposite birds’ flight capabilities were so good that they drove all but the largest pterosaurs to extinction. How many times do I need to repeat the same facts?
Hoatzin chicks have two claws, which they use when threatened by predators to crawl out of their nests before they can fly, as their parents try to divert the attackers. The chicks also can drop into swamp water, then climb back up to the nest. Most if not all modern birds lose their claws in adulthood, but most if not all opposite birds retained them, just as most but not all had teeth. It doesn’t mean that opposite birds were worse fliers than hoatzins. Had you ever studied evolution, these facts & inescapable conclusions would not surprise you.
Modern birds survived not because they were better fliers but due to other abilities & behaviors, plus where they lived. Again, I’ve repeatedly presented evidence to this effect. Here’s a new one, ie better sense of smell:
http://www.livescience.com/13682-birds-survived-mass-extinction-dinosaurs.html
As for marine reptiles, why do you keep ignoring sea snakes, turtles & crocs? Of course the Interior Seaway had retreated, but that created shallow habitat elsewhere. It still existed over the US, but had receded from Canada by the K/T. Mosasaurs & plesiosaurs had global distribution, but everywhere avoided ocean depths. Their prey lived near the surface.
These two groups of marine reptiles died out not because they had to swim from lower depths but because their main food sources, belemnites (plesiosaurs) & ammonites (mosasaurs), went extinct due to the effects of the impact on ocean chemistry & primary production. For larger mosasaurs, it was their plesiosaur prey that failed, following loss of belemnites. Many if not all plesiosaurs were bottom feeders, gliding over continental shelf shoals looking for food.
Both mosasaurs & plesiosaurs gave live birth, which would necessarily have been in shoals, so that their young could breathe. Please quit trying to make up excuses, but rather study & think.
There is zero evidence in support of your idea & all the fact & reasoning in the world against it. Sorry.
PS: As noted before, modern birds’ new nesting strategies, which obviated the benefit of chicks growing claws, is one reason scientists have assessed for their survival of the impact. Like many birds today, Cretaceous neornithes nested in hides on marshy ground, on cliff faces, in cavities in trees & in burrows, not just on tree branches.
Many, like ratites, had already lost the ability to fly. Same applies to partially toothed relatives of neornithes, like Hesperornis. Young ratites still retain vestigial wing claws today, as do some flying species besides hoatzins, like turacos & yellow rails. Note that all these are Gondwanan birds, except the yellow rail, which oddly is a marsh dweller. But that’s evolution for you.
@John Tillman
Let’s be honest about it, neither one of us will be able to prove that archaic birds had the same flight ability as the neornithes. The few bones and feather imprints are not sufficient evidence to establish this. We are both giving our personal opinion.
I read your link and find the sense of smell explanation incredulous. If the airborne debris from the impact played a role in the extinctions, birds with the more sensitive sense of smell would have been more vulnerable.
You are basing your analysis on the assumption that the impact was the cause of the extinctions. In other words, you believe in an instantaneous (geologically speaking) extinction.
I believe that surface gravity was gradually increasing during the late Cretaceous with a rapid pulse near the end. The theory posted requires the rapid pulse of surface gravitation when a large rapid marine regression occurs. A large eruption of flood basalt volcanism must also occur (usually lagging the extinctions). If you study all the mass extinctions, these two scenarios are common to all mass extinctions.
Hopefully, in the near future, the scientific community will finally agree on the definitive cause(s) of the K-T extinctions.
@LarsP
“So please John, try to do the math and run the numbers. There is no use to continue the discussion without showing a calculation.”
What math would you like to see? Be specific.
Staten-John says:
March 30, 2013 at 9:34 am
What math would you like to see? Be specific.
What variations in gravity are you talking about.
I already asked in the very first post specifically this:
March 29, 2013 at 10:36 am
…before any discussion about an increase in gravity, please try to run the numbers and check what variations in gravity would be achieved…
The scientific community has already agreed on the cause. I posted the link here. It’s not consensus science but the overwhelming preponderance of the evidence. Skeptics have had decades to destroy the impact theory without making a dent.
Had you read any of the links I’ve posted you’d know that there was a great diversity of avian life at the end Cretaceous. It doesn’t matter if you imagine, contrary to all evidence, that opposite birds couldn’t fly as well as more “modern” groups. As I said in my first comment on this topic, many modern & modernish birds went extinct at the K/T along with the most “primitive” opposite birds.
For instance, the common shore bird Ichthyornis was “modern” in all respects except teeth. Its wings lacked claws. Same goes for the related diving bird genus (flightless like penguins & great auks) Hesperornis. They belonged to the group Ornithurae, sister taxon to Enantiornithes, the opposite birds. The Ornithurae include both “archaic” forms like the sea & shore bird genera mentioned & the Neornithes. Here’s a chart from one of my posted links showing these relationships for a community at the K/T boundary in western North America:
http://www.pnas.org/content/108/37/15253/F4.large.jpg
But then opposite birds were in fact good fliers. If you suppose not, then please explain what purpose you imagine for the anatomical details I pointed out. The burden of proof is on you to show that they couldn’t fly well, since all informed thought on the subject concludes that they could.
In any case, it wasn’t their flying ability that doomed the opposite birds. The basal & derived Ornithurae, most of which (except some modern groups & possibly one non-neornithes, as noted previously) went extinct along with the Enantiornithes, had the shoulder joint configuration of modern birds (which facilitates the up stroke), so there goes that lame excuse of yours. Not all their fossils show the birds’ hands, so we don’t know if most Cretaceous ornithurae lacked claws like moderns, but probably so, since the most basal forms, like Ichthyornis did. We often lack their skulls, too, so don’t know how common teeth might have been among the non-neornithes ornithurae.
I wouldn’t have to waste time providing you with all this info had you bothered to read the links I’ve posted. And if you were willing to think.
Staten-John says: I believe that surface gravity was gradually increasing during the late Cretaceous with a rapid pulse near the end. The theory posted requires the rapid pulse of surface gravitation when a large rapid marine regression occurs. A large eruption of flood basalt volcanism must also occur (usually lagging the extinctions). If you study all the mass extinctions, these two scenarios are common to all mass extinctions.
*******************************************************************************************
Forgot to respond to this blatant falsehood.
You clearly have not studied all mass extinction events. Your two scenarios most certainly are not common to all of them. Contrary to your assertion, the O/S extinction occurred when volcanism ceased. The marine regression at that time followed glaciation. It had nothing to do with gravity pulses. The prior Cambrian extinctions are also associated with glaciation. The following Devonian extinction coincided with marine transgression, not regression.
Have you considered actually studying the science to which you wish to contribute?
If you want to overturn a scientific paradigm, then do as real scientists have done in the past & spend decades assembling data & couching argument, as did Copernicus & Darwin. Then show how your hypothesis better explains observed reality than the prevailing consensus, in detail. For starters, how about showing the superiority of your explanation for the disappearance of belemnites & ammonites, followed by their predators mosasaurs & plesiosaurs, over those based upon the K/T impact?
Then show in the case of every other group which went extinct at the K/T how the impact theory fails & your alternative scheme succeeds. Also of course provide evidence that terrestrial gravity actually behaved as you suppose, & that it could have produced the observed extinctions.
You haven’t & can’t so you’re falsified before you even begin. Idle speculation doesn’t cut it, sorry.
PS: If all MEEs have the same cause, then explain please why trilobites survived the Cambrian, Ordovician & Devonian extinctions finally to succumb only in the Permian, Mother of All MEEs. Similarly, why did ammonites survive the Devonian, Permian & Triassic events but not the Cretaceous?
Also, why did shallow water-dwelling ammonites & belemnites perish at the K/T, while deep-living nautiluses came through, if gravity be the cause of the MEE?
The K/T impact has the distinct advantage of actually having happened at the precise moment in geohistory that all those lifeforms went extinct. OTOH, there is zero evidence for the gravity pulses you imagine. Zip, nada, bupkus.
@John Tillman,
“Archaic birds, just like modern birds, had brains adapted for flight control.”
This statement, like all of your statements are just your opinion, nothing more. There is just no way you can prove that statement.
No, the smaller pterosaurs were driven to extinction because an increasing surface gravity mandated that they increase their wing area to body mass ratio. The only way they could do that was to also increase their body size.
You now start to use extant birds (i.e., Hoatzin chicks) to birds over 65 million years old regarding claw usage. I cannot spend time pointing out all of your illogical comparisons.
If you really want to have some credibility explain why Enantiornithine B went extinct before Enantiornithine A. Obviously the impact was not responsible.
As far as the ammonites going extinct but not the nautilus, you will find a detailed explanation in the book with the same name as the theory. They were quite different structurally and the ammonite changed substantially between the P-T extinction and the K-T extinction while the nautilus did not.
If you studied the mass extinctions you mention you would know that the glaciation involved was insufficient to cause the associated regressions. And you might want to try to explain why the sea level at the end of the Permian (i.e., no glaciation) was lower than it is today (i.e., with glaciation).
http://en.wikipedia.org/wiki/File:Phanerozoic_Sea_Level.png
“Have you considered actually studying the science to which you wish to contribute?”
I would ask you the same question.
@LarsP
“What variations in gravity are you talking about.
I already asked in the very first post specifically this:
March 29, 2013 at 10:36 am
…before any discussion about an increase in gravity, please try to run the numbers and check what variations in gravity would be achieved…”
If you are asking what percentage drop in surface gravity occurred I would guess at least 50% based on the size of the largest fauna. It could be more.
This is the number used in the book with the same name as the theory we are discussing. The mass of the shifted core elements (inner core, outer core and densest part of lower mantle) which represents about 85% of the total mass of the Earth had to move away from Earth centricity to cause the lower surface gravity on Pangea.
You provided Newton’s equation for the force of gravity in an earlier post. I assume you can solve this simple equation. Use that equation to calculated the shift needed for a 50% reduction in the force of gravity on Pangea. Give the answer in a fraction of the Earth’s diameter needed for the shift.
Staten-John says:
March 30, 2013 at 6:19 pm
A load of garbage…
http://en.wikipedia.org/wiki/File:Phanerozoic_Sea_Level.png
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So much ludicrously, ridiculously wrong; so little time.
How many times do I need to show you from actual anatomy that the traits of opposite birds & their early modern kin are not matters of opinion but fact? Do you know the difference?
The brains of the earliest opposite birds were intermediate between that of Archaeopteryx & modern birds. Adaptations for powered flight are plain in the brains of birds, as of pterosaurs. It’s also possible to infer whether they fed by day or night, whether they were precocial & much else about their lives & behavior. Forming opinions on these topics has to be based upon observation, which sometimes leads only to one conclusion.
How exactly is it “illogical” to infer behavior of extinct birds from that of modern birds? Scientists often use modern analogies to reconstruct past behavior from living relatives & even not closely related ecological analogues. Had you ever studied any of the relevant disciplines, you’d know this. It has been repeatedly shown a valid technique.
It’s obvious you still haven’t read the paper from which I linked the chart, although I posted it early in this thread. Both Enantiornithines A & B are from the same horizon at the K/T boundary. They went extinct at the same time. The slight displacement of B relative to all the other ultimate dots is a tiny typo, as would be obvious had you bothered to educate yourself, which you’re clearly either afraid or too lazy to do.
The fact remains that your ignorant assertion that birds did not go extinct at the K/T has been falsified every which way. The vast majority of birds went extinct along with their dinosaur kin. This includes lots of modern birds & semi-modern birds like members of the Ichthyornis & Hesperornis families. Opposite birds were already on their way out by 66 Ma.
You commit the logical fallacy of begging the question (assuming what you intend to prove) by asserting without the slightest actual evidence that pterosaurs were going extinct due to gravity changes.
You failed to explain why belemnites & ammonites didn’t go extinct during prior MEEs, which you suppose all occur because of imaginary “gravity pulses”. Ammonites survived the devastating P/T, along with the prior D/C & later Tr/J MEEs. They constantly evolved, both in shell form but also physiology & reproduction from their straight-shelled Silurian ancestors. Their rapid evolution is what makes them such good stratigraphic markers.
Ammonites were in decline in the LK, although as usual evolving new shapes. The order was reduced to a few families but their final disappearance was too sudden (along with belemnites) to be explained by background natural extinction. The impact affects would thuns have hit them harder than nautiloids because ammonite larva were planktonic, high in the water column. Nautiloid eggs are large & stay deeper.
Also, ammonite shells were composed of aragonite (mother of pearl), which would have been highly susceptible to acid rain from the vaporizing & lofting enormous beds of limestone into the atmosphere by the impact. The deeper-water nautilus was more protected. Maybe ammonites lost out to other competitors for the scarce resources left after the bolide hit.
Nautiluses have changed less because they continued to inhabit more stable, benthic environments.
To which glaciation do you refer in not being able to account for the marine regression? I cited the O/S. Please present some evidence to support this unfounded assertion. Paleontologists & geologists who have actually studied the Ordovician glaciation adamantly disagree with you:
http://www.ucmp.berkeley.edu/ordovician/ordovician.php
“During the Upper Ordovician, a major glaciation centered in Africa occurred resulting in a severe drop in sea level which drained nearly all craton platforms. This glaciation contributed to ecological disruption and mass extinctions…Climatic fluctuations were extreme as glaciation continued and became more extensive. Cold climates with floating marine ice developed as the maximum glaciation was reached.”
You are aware are you not that Pangaea was long gone by the K/T boundary? It started splitting up in the Late Triassic, about 200 Ma. By the Late Cretaceous, 66 Ma, Earth more resembled now than the Early Triassic, with isolated continents. Parts of Gondwanaland were still connected, but Africa & South America had separated, as had all the parts of Laurasia.
Now we come to the most hilarious part. The chart you show of reconstructed sea level neatly makes my point, not yours. Both its curves plainly show marine transgression at the Devonian MEE, as I told you, not regression as you so falsely claimed for “all” extinctions. You have not ever studied MEEs before. I have. All you imagine you “know” comes from a readily falsified book without a shred of supporting evidence for its underlying speculation.
Please don’t comment again until you have taken the time to study, learn & think.
PS: I also note that you failed to respond to this question: “If all MEEs have the same causes, namely “gravity pulses” & marine regression (which of course is not the case), why then did trilobites survive the Late Cambrian, end-Ordovician & Late Devonian extinctions, only to succumb in the end-Permian, & why did ammonites survive the Devonian, Permian & end-Triassic events, only to perish in the end-Cretaceous?”
@John Tillman,
Again, I have asked specific questions and you evade them. I’ll try once more in the hope you will answer them.
1.Explain why Enantiornithine B went extinct before Enantiornithine A. If the chart you linked to has an error, PROVE IT!
2. Explain why the sea level drop at the P-T interval resulted in sea levels lower than they are today base on the Wiki sea level chart linked to. Glaciation was absent in the former but present in the latter.
Regarding the survival of the nautilus and the ammonite at the K-T interval, I already explained that the two are significantly different structurally. For example, the siphuncle runs through the center of the septa while it runs along the ventral periphery of the ammonite. During the Cretaceous ammonites started to increase shell thickness, tubercles and more robust spines. The nautilus has a thicker shell extending its implosion depth. Read Peter Ward’s books which indirectly support the theory I support. Regarding the extinction of the ammonites at Zumaya where he could not find ammonite fossils at or just below the K-T boundary, he stated:
“ …at the end of the Cretaceous, Zumaya was in the deepest part of the basin, at depths too great to sustain many ammonites.”
Regarding the tribolites becoming extinct at the P-T transition, there are two reasons:
1. The rapid pulse of increasing surface gravity on Pangea which, if you read the pdf cited, is explained.
2. At this point in time, the massive drop in sea level with surface gravity still lower than it is today coupled with the warm sea level temperature, massive amounts of methane were released from the epicontinental seas (i.e., the hydrates were exposed to low water pressure and high sea water temperature). The delta 13C graphs support this. The Siberian Traps enhanced this process. This second condition was not present in the prior mass extinctions.
Staten-John says:
March 31, 2013 at 9:11 am
@John Tillman,
Again, I have asked specific questions and you evade them. I’ll try once more in the hope you will answer them.
1.Explain why Enantiornithine B went extinct before Enantiornithine A. If the chart you linked to has an error, PROVE IT!
******************************
As I pointed out, it’s easy to prove. Just read the article. They both went extinct at the same time. How lazy can you be?
***********************************
2. Explain why the sea level drop at the P-T interval resulted in sea levels lower than they are today base on the Wiki sea level chart linked to. Glaciation was absent in the former but present in the latter.
**************************************
Can you read? For the third time, I was talking about the Ordovician, not the Permian. The O/S falsifies your unfounded assertion about “all MEEs”, as does the Devonian.
*****************************************
Regarding the survival of the nautilus and the ammonite at the K-T interval, I already explained that the two are significantly different structurally. For example, the siphuncle runs through the center of the septa while it runs along the ventral periphery of the ammonite. During the Cretaceous ammonites started to increase shell thickness, tubercles and more robust spines. The nautilus has a thicker shell extending its implosion depth. Read Peter Ward’s books which indirectly support the theory I support. Regarding the extinction of the ammonites at Zumaya where he could not find ammonite fossils at or just below the K-T boundary, he stated:
“ …at the end of the Cretaceous, Zumaya was in the deepest part of the basin, at depths too great to sustain many ammonites.”
******************************************
Of course they’re different. Ammonites, like the mosasaurs that fed on them, inhabited shallow waters, contrary to your prior baseless assertions. Nautiloids lived deeper in the ocean, so were sheltered from the worst effects of the impact. Your drivel about gravity makes no sense at all, since the effect is scarcely measurable & in any case Pangaea had been breaking up for 135 million years by the K/T.
None of which verbiage answers the question, “Why didn’t ammonites go extinct in the Devonian, Permian or Triassic MEEs, if only gravity & regression are always to blame?
**********************************
Regarding the tribolites becoming extinct at the P-T transition, there are two reasons:
1. The rapid pulse of increasing surface gravity on Pangea which, if you read the pdf cited, is explained.
2. At this point in time, the massive drop in sea level with surface gravity still lower than it is today coupled with the warm sea level temperature, massive amounts of methane were released from the epicontinental seas (i.e., the hydrates were exposed to low water pressure and high sea water temperature). The delta 13C graphs support this. The Siberian Traps enhanced this process. This second condition was not present in the prior mass extinctions.
************************************************
Oh, so now it doesn’t take just gravity & regression, but also volcanism. How about bolide impacts? They never have any affect in your cockamamie scheme?
How does a “pulse” of gravity work on a supercontinent forming over hundreds of millions of years & staying conjoined for on the order of 100 million years? It is to laugh.
BTW, you mean P-Tr, not P-T.
Why don’t you ask Peter Ward what he thinks about your anti-scientific fantasy? That should be educational for you & amusing for others.
ward.biology.uw@gmail.com
Argon/argon dating provides the smoking planet (even without global fires).
http://www.sciencemag.org/content/339/6120/684
Coincidence & correlation don’t always equal causation, but in a scenario as plausible as this, with so many effects directly attributable to a bolide impact, it would be perverse not to consider the case closed pending further evidence or interpretation.
BTW, if the Siberian Traps could contribute to the P/Tr MEE, then why not similar volcanism at the Tr/J & K/Pg events, Staten-John, not to mention the impact in the latter case?
Staten-John says:
March 30, 2013 at 6:37 pm
bla bla bla … 50% … bla bla bla
Sorry John, there is no math in your answer.
If you want to get knowledge why it happened you can read here:
http://agadorie.wordpress.com/2013/01/28/the-second-truth/
@John Tillman,
Again, I have asked specific questions and you evade them. I’ll try once more in the hope you will answer them.
1.Explain why Enantiornithine B went extinct before Enantiornithine A. If the chart you linked to has an error, PROVE IT! If it is an error post a quote from the website associated with the chart you provided a link to. How lazy can you be?
2.Explain why the sea level drop at the P-T interval resulted in sea levels lower than they are today base on the Wiki sea level chart linked to. Glaciation was absent in the former but present in the latter. This question was asked because you cited glaciation as the cause of the massive regression in prior mass extinction events. Since glaciation didn’t cause the massive regression at the P-T (yes that’s the Permian-Triassic) transition why do you insist it did at earlier mass extinctions?
What kind of logic do you use……how does my statement falsify anything?
Your comments about ammonites and nautiloids show your lack of knowledge. They both rise to the surface at night. Therefore the impact could not have affected one and not the other.
Pangea broke up at an insignificant rate (of separation) for most of the Mesozoic. You obviously don’t know anything about how angular momentum works otherwise you would not have made this statement. The continents don’t have to be attached to each other to affect angular momentum; it is their total latitudinal movement that’s important. If you don’t know basic physics you will never understand the theory.
You wrote in response to my explanation of why the tribolites went extinct due to the combined effects of higher surface gravity and the release of methane from the frozen hydrates at the sea floor:
“Oh, so now it doesn’t take just gravity & regression, but also volcanism. How about bolide impacts? They never have any affect in your cockamamie scheme?”
Clearly you have a reading comprehension problem.
Your insistence that the K-T extinctions were the result of an asteroid impact forces me to ask you a question (which I hope you don’t try to evade):
Would you be affected, either economically or otherwise, if the asteroid impact theory
is definitively proved wrong? Have you published any work that supports that theory?
Staten-John says:
Please try to think about it. Moving the core around would only influence surface gravity by a few percent.
The difference in mass between the core and other parts of the planet just aren’t that great. Regardless, where does the energy come from that is going to move the core away from the center? Any movement away from the center of the earth is by definition, moving uphill.
“birds has tens of thousand of years to evolve flight compensation for differences in air pressure.”
The sea creatures had the same amount of time to adapt.
george e. smith says:
March 28, 2013 at 4:10 pm
The impact will create a shock wave that will blast a hole in the atmosphere in all directions for hundreds of miles.
John Tillman says:
March 29, 2013 at 8:30 am
The lower level of O2 detected in the early Paleocene does however suggest at least regional firestorms.
—
Rotting vegetation would also consume oxygen and with much of the plant life killed off, it would take a long time to replace that oxygen.
No, the smaller pterosaurs were driven to extinction because an increasing surface gravity mandated that they increase their wing area to body mass ratio. The only way they could do that was to also increase their body size.
Higher gravity also means denser air.
The need to increase surface area would have been minimal.
MarkW,
Please don’t misquote me, I didn’t make that statement about birds and air pressure.
If you want to know what force it took to move the core elements (all three of them), study the conservation of angular momentum. Specifically what happens when Pangea (in whole or broken up) moves to higher latitudes.
Higher gravity does mean denser air but since at the time we are considering, surface gravity was lower than it is today, therefore the air density was also lower than it is today.
Staten-John:
I have evaded nothing. I have repeatedly provided all that a sane person of normal intelligence would need. You have ignored everything dispositive of your fantasy.
1) Read the article. It’s short, so that even with a challenged attention span, you should be able to handle it. The whole point is that all the species discussed survived to within 300,000 years of the K/T event. ALL includes both Enantiornithes A & B. Read it, then get back to me. I’ve provided you the link at least twice. Here it is again:
http://www.pnas.org/content/108/37/15253.full
If the whole thing is too much for you, here’s a bit of the abstract:
“Here, we describe a diverse avifauna from the latest Maastrichtian of western North America, which provides definitive evidence for the persistence of a range of archaic birds to within 300,000 y of the K–Pg boundary. A total of 17 species are identified, including 7 species of archaic bird, representing Enantiornithes, Ichthyornithes, Hesperornithes, and an Apsaravis-like bird. None of these groups are known to survive into the Paleogene, and their persistence into the latest Maastrichtian therefore provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact.”
Does everyone always need to hold your hand for you like this? Apparently, since you fell for such an idiotic on its face farce as the gravity “hypothesis”. Here’s the first paragraph of the Results section, showing yet again no time difference whatsoever in the disappearance from the fossil record of both Enantiornithes A & B:
“A total of 15 distinct coracoid morphotypes are identifiable; full descriptions of each are given in the SI Appendix. One enantiornithine has previously been recognized from the assemblage (27), but three species are identified here (Fig. 1 A–C). The largest (Fig. 1A) most likely represents the giant enantiornithine Avisaurus archibaldi (27). Enantiornithine features (31) include a dorsal fossa, a posteriorly projecting coracoid boss, a dorsally oriented glenoid, and a medial fossa, but the coracoid lacks a supracoracoideus nerve foramen or a medial flange and groove. Enantiornithine A (Fig. 1B) is a smaller taxon, characterized by a deep medial fossa, a thin medial flange, and a subtriangular coracoid neck. The smallest form, Enantiornithine B (Fig. 1C), is differentiated by a bulbous, medially notched scapular condyle, a robust medial flange, and an elliptical coracoid neck. provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact.”
If you don’t believe me or the plain evidence of the text, contact the authors of the paper.
2) Can you possibly really be this dense? For the third time, I pointed out that, contrary to your easily shown false assertion that all MEEs have the same causes, ie marine regressions caused by “gravity pulses” & volcanism, the Ordovician event followed the end of volcanism & its sea level regression was caused by glaciation. What possible relevance could the P/Tr (please not correct abbreviation, yet again), about which I said nothing, have to do with this argument? You also continue to evade the inconvenient truth that the Devonian extinctions were accompanied by marine transgression.
3) You clearly have never, ever studied marine biology in general or cephalopod behavior & evolution in particular. Your assertion that nautiloids rise at night to the same level as ammonites inhabited is laughable. Ammonites lived their entire lives above about 100 meters in depth. Nautiloids even when rising at night from 900 to 2000 feet, rarely if ever got as high as 100 meters. Normal for modern Nautilus species is 500 to 300 feet, just 30 feet within the the 100 meter level for fleeting moments if at all. There would have been no reason for them to rise even that high during the K/T event. Most of their food at those shallow depths would have been dead.
4) Apparently you have never looked at a map of Pangaea. In the NH, there was more land at high latitudes while it was conjoined than at the K/T (bear in mind that continental crust can lie under shallow seas). In the SH, about the same amount lay above 60 degrees South, if less above 70 or 80. In any case, the effect would have been tiny, as elementary arithmetic would show any sane person of normal intelligence. The oceanic & continental crust is a minute fraction of the diameter & mass of the earth. The slight differences in its distribution are less than trivial.
5) I have no vested interest in the K/T extinction. I am interested in the integrity of science. Advances & new paradigms, overturning orthodoxies, have never arisen from the lunatic fringe, but from real, hard-working, brave honest scientists doing valid research or calculation for lifetimes, like Copernicus, Kepler, Galileo, Newton, Lavoisier, Darwin, Wegener & Bretz, whose work is as different from your idle, baseless, prima facie false speculation as is humanly possible.
PS: I would add the Alvarezes to that list of great paradigm-shifters. Had you ever actually read their work or the hugely productive research that has followed in the wake of their hypothesis, now a well-established theory, maybe you could have saved yourself a lot of public embarrassment.
@John Tillman,
The following is a quote from another website which displayed the same chart you posted:
“The effect of the Cretaceous-Paleogene (K-Pg) (formerly Cretaceous–Tertiary, K–T) mass extinction on avian evolution is debated, primarily because of the poor fossil record of Late Cretaceous birds. In particular, it REMAINS UNCLEAR whether archaic birds became extinct gradually over the course of the Cretaceous or whether they remained diverse up to the end of the Cretaceous and perished in the K–Pg mass extinction.”
The emphasis of “remains unclear” is mine and 300,000 years is a long time.
If you don’t think nautiloids come to the surface of the water at night then read Peter Ward’s books.
You wrote in an earlier post:
“The impact affects would thuns have hit them harder than nautiloids because ammonite larva were planktonic, high in the water column. Nautiloid eggs are large & stay deeper.”
Now you write:
“Ammonites lived their entire lives above about 100 meters in depth.”
YOU KEEP CONTRADICTING YOURSELF!
You wrote:
“I pointed out that, contrary to your easily shown false assertion that all MEEs have the same causes, ie marine regressions caused by “gravity pulses” & volcanism…..”
Your density is showing again. Let me explain it, hopefully one last time.
The core elements (all 3 of them) are able to move off-center when a large continental mass (especially a supercontinent) moves latitudinally so that its center of mass moves away from the equator. When that happens surface gravity lowers. When the reverse happens, surface gravity increases causing extinctions. Coeval with the gravity increase sea level drops which can release methane from the sea bottom, causing another wave of extinction, bot on land and in the sea. Flood basalt volcanism results from the core elements moving back toward Earth-centricity, which is initiated at the core mantle boundary and takes an extended period of time before it reaches the surface.
If you don’t understand why the continental plate movement shifts the core elements then pick up an elementary physics book and read about the conservation of angular momentum.
The regression is followed by a transgression, which you have noted concerning the Devonian but is common to all mass extinctions.
I can make no sense of your ramblings about the land distribution of Pangea, north and south. If you read the pdf link I provided you should know, based on the charts provided by the French research group, that Pangea moved well south of the equator prior to 250mya and well north of the equator after 250mya. Do I have to hold your hand?
If you know anything about those scientists you listed, you would know they were all considered crackpots until their theories were accepted.
@John Tillman,
You might want to read Peter Ward’s book ‘ In Search of Nautilus’ in which you will find the following quote:
“Soon after nightfall large specimens of Nautilus macromphalus can be seen in the shallow areas of the outer barrier reef.”
The Alvarez’s theory about extinction will eventually be discarded. It’s only a matter of time.
I have read it. Apparently you have not. Nor did you read what I said.
Nautiluses seldom get as high as the 100 meter level, which was about the floor for ammonites, as I tried to educate you.
Ward considers “shallow” to be 160 to 225 meters:
PLoS One. 2011 Feb 22;6(2):e16311. doi: 10.1371/journal.pone.0016311.
Vertical distribution and migration patterns of Nautilus pompilius.
Dunstan AJ, Ward PD, Marshall NJ.
Source
School of Biomedical Science, University of Queensland, Brisbane, Queensland, Australia. andy.dunstan@gmail.com
Abstract
Vertical depth migrations into shallower waters at night by the chambered cephalopod Nautilus were first hypothesized early in the early 20(th) Century. Subsequent studies have supported the hypothesis that Nautilus spend daytime hours at depth and only ascend to around 200 m at night. Here we challenge this idea of a universal Nautilus behavior. Ultrasonic telemetry techniques were employed to track eleven specimens of Nautilus pompilius for variable times ranging from one to 78 days at Osprey Reef, Coral Sea, Australia. To supplement these observations, six remotely operated vehicle (ROV) dives were conducted at the same location to provide 29 hours of observations from 100 to 800 meter depths which sighted an additional 48 individuals, including five juveniles, all deeper than 489 m. The resulting data suggest virtually continuous, nightly movement between depths of 130 to 700 m, with daytime behavior split between either virtual stasis in the relatively shallow 160-225 m depths or active foraging in depths between 489 to 700 m. The findings also extend the known habitable depth range of Nautilus to 700 m, demonstrate juvenile distribution within the same habitat as adults and document daytime feeding behavior. These data support a hypothesis that, contrary to previously observed diurnal patterns of shallower at night than day, more complex vertical movement patterns may exist in at least this, and perhaps all other Nautilus populations. These are most likely dictated by optimal feeding substrate, avoidance of daytime visual predators, requirements for resting periods at 200 m to regain neutral buoyancy, upper temperature limits of around 25°C and implosion depths of 800 m. The slope, terrain and biological community of the various geographically separated Nautilus populations may provide different permutations and combinations of the above factors resulting in preferred vertical movement strategies most suited for each population.
Here’s a graph of their recorded movements, since actually reading & absorbing text appears to be beyond your ability:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3043052/figure/pone-0016311-g003/
Ward, like everyone else, uses ROVs & cameras to study them. You can’t sit in a boat on the surface & see them at night. They’re mostly below 150 meters, precisely as I told you. Had you bothered to do any actual research in looking to support your lunatic fantasy, you’d already have learned this.
BTW, deep-diving nautiluses are so hard to study that people have died doing so.
Please state what findings you think could possibly falsify the Alvarez’ impact theory, which has withstood attack from every possible angle for over 30 years? Walter states that the impact was preceded by other stresses on life preceding it, such as land volcanism (Deccan Traps) & marine regression (due to lowered undersea volcanism, a slightly cooler climate & possibly other causes). But study after study has found that the mass extinctions occurred almost simultaneously (within ability to measure) with the now well-date impact. The bird study you refuse to read is one.
@John Tillman,
Let me add the text that was in Ward’s book:
“….have observed what native fisherman have long known: soon after nightfall large specimens of Nautilus macromphalus can be seen in the shallow areas of the outer barrier reef.”
I’ll rely on Ward’s expertise rather than a study you offer. I didn’t see the number of tagged specimens used in the study nor whether it was conducted near a reef, which would offer protection to the nautilus to ascend higher.
Also, describing what the nautilus fed on, the spiny lobster genus Panulirus, he stated that they live on the top 30 to 40 feet of the outer reef (in New Caledonia).
Even your reference states:
“The slope, terrain and biological community of the various geographically separated Nautilus populations may provide different permutations and combinations of the above factors resulting in preferred vertical movement strategies most suited for each population.”
The Alvarez theory, after 30 years is still not accepted. Yes, the impact did occur at that time but two other theories are debated, volcanism and my theory.
If the Alvarez theory were valid there would be a lot of “bone piles” near the clay layer. Where are they? I’m not aware of any, are you?
The reality is that dinosaurs were disappearing gradually over the late Cretaceous and fossils in the 3 meter depth below the clay layer are minuscule.
The theory I support (increasing surface gravity) is the only one that can explain the observed effects. Even the extinction of all marsupials in N. America supports this theory.
“But study after study has found that the mass extinctions occurred almost simultaneously (within ability to measure) with the now well-date impact. The bird study you refuse to read is one.”
The assumption that all the extinctions took place at the time of the impact instead of some other time within the 300,000 year has no basis.
“Cum hoc ergo propter hoc”
Are you blind?
The study I showed you was by Ward & a colleague. Do you read?
When Ward says “shallow”, he means relative to the depths at which nautiluses spend most of their time. Again I ask, can you really be this dumb?
Clearly paleontology & geology are also sciences you’ve never studied. There would not be bone piles at the boundary because very few living things ever fossilize, which should be obvious. Collections within 300,000 years are at the resolution ability, as you’ve been shown over & over by actual paleontologists. That’s the blink of an eye in geological time.
The Alvarez’ theory isn’t an example of cum hoc. It’s an explanation for the extinctions that had already been observed, long before. Science has now been able to fix the dates of both the impact & the extinctions more closely, & yes, they do correlate as precisely as can be measured. But the clincher for the theory is that it explains the pattern of extinctions, which your fantasy fails miserably to do.
The extent to which non-avian dinosaurs were in decline is highly controversial. Your assertion overlooks mountains of evidence. To the extent that there is a consensus now, it favors dino diversity right up to the impact (see Wang, 2006, & ), Barrett’s 2009 study notwithstanding. Older work supporting lower late Maastrichtian diversity suffered from poor sampling & taphonomic problems.
But of course actually researching this topic would require too much work for you.
http://bsgf.geoscienceworld.org/content/183/6/547.abstract
But even if non-avian dinos were in decline (as pterosaurs certainly were, probably due to birds), that would not obviate the robust conclusion that the impact wiped them out long before they would have gone extinct at a background rate. Indeed, they might still be with us to some extent, as are birds. The smallest dino known lives right now in Cuba. Of course a tinier bird would be unlikely to be found as a fossil.
@John Tillman,
Your immature comments show that you are the one that is dumb and getting desperate. If it is too hot in the kitchen……………..
The missing “bone piles” at the K-T transition cannot be attributed to the Signor Lipps effect. Your entire support of the impact’s responsibility for the extinctions is unsupportable. If 75% of species were killed by the asteroid, which would have happened within days, months and less likely, years, there would be many “bone piles.”
As I’ve tried to explain to you, pterosaurs were gradually getting larger (wing area/body mass ratio) during the late Cretaceous to compensate for a gradual increase in surface gravity. The rapid high pulse of increasing surface gravity at the K-T transition would have had to be coeval with the massive marine regression if the Gravity Theory of Mass Extinction is valid. This is the reason the pterosaurs as well as all other terrestrial fauna that disappeared became extinct. It had nothing to do with competition from birds, which were minuscule compared to pterosaurs.
The 300,000 year window of extinction is your crutch!
Cum hoc ergo propter hoc!
There is no reason to imagine we would have discovered any bone piles. There may be some fossilized piles in the crust of the earth at the K/T boundary, but the odds of finding them in the few outcrops of the right age are vanishingly small. The resolution of 300,000 years is a taphonomic fact, not a crutch.
The mass extinction is visible in the fossil record because many species below the line don’t exist above the K/T boundary. That their near-simultaneous disappearance was rapid is evident in the record as well.
Pterosaurs did not slowly get larger during the Maastrichtian. They were already large. An azhdarchid vertebra was reported in 2010 from the EK (~140 Ma) & genus Lacusovagus is known from ~120 Ma. But this family of giant pterosaurs is primarily found in the LK (108 Ma) & was the only one known still extant at the K/T, although many genera in it had already gone extinct by then. There were also other giant (wingspan 16-36′) families which died out in the EK & LK long before the K/T, like the genera Ornithocheirus, Coloborhynchus, Cearadactylus, Caulkicephalus Liaoningopterus (same family as preceding four), Pteranodon, Geosternbergia (same family as Pteranodon), Moganopterus, Santanadactylus & Istiodactylus. So yet again your total ignorance is on humiliating display.
What is noticeable during the LK is the progressive extinction of small pterosaurs, due to competition from birds. Only the few largest arzhdachid species survived to be wiped out by the impact. They are a fascinating family. You should study them before commenting on their evolution, the nature of which falsifies your baseless assertion.
The so-called “Gravity Theory” isn’t a theory, isn’t valid & in fact is completely without a single shred of supporting evidence.
Your willful ignorance & lame excuse making are aggravating. It’s the wrestling with a lunatic pig syndrome, which I’ve been crazy not to avoid.
@John Tillman,
Based on your immature comments I have to assume you are still in high school.
Your support of the asteroid impact hypothesis is based on conjecture only, because you cannot and have not provided any references to dinosaur fossils that can be linked to the proximity of the clay layer. You can make all the excuses that you like but you will never find those references. There were few, if any, dinosaurs alive at the time of the impact.
Yes, I misspoke when I stated that the pterosaurs were getting larger in the late Cretaceous. I should have omitted the adjective “late.” Pterosaurs were getting larger throughout the entire Cretaceous because they were evolving in an environment where surface gravity was increasing. If you have another explanation for the size increase, please provide it.
The Gravity Theory of Mass Extinction can explain ALL mass extinctions, the common cause of which is an increase in surface gravity. I will repeat my prior post:
The core elements (all 3 of them) are able to move off-center when a large continental mass (especially a supercontinent) moves latitudinally so that its center of mass moves away from the equator. When that happens surface gravity lowers. When the reverse happens, surface gravity increases causing extinctions. Coeval with the gravity increase, sea level drops which can release methane from the sea bottom, causing another wave of extinction, both on land and in the sea. Flood basalt volcanism results from the core elements moving back toward Earth-centricity, which is initiated at the core mantle boundary and takes an extended period of time before it reaches the surface.
View Figure 11 in the following study of the Triassic-Jurassic extinction. The chart, if you examine it carefully, is precisely what the GTME would predict for all mass extinctions. However, as noted in a prior comment, the release of methane in pre-Permian extinctions would be absent because it was the Carboniferous period where massive amount of carbon were buried at the sea bottom forming the methane hydrates.
http://onlinelibrary.wiley.com/doi/10.1111/pala.12034/full