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Fraser
2006-Oct-26, 12:20 AM
How did the dinosaurs die? It's a question scientists have been trying to figure out since their fossils were first discovered. Most believe that it was a giant asteroid that stuck the Yucatan peninsula 65 million years ago, and ended the dinosaurs' reign on Earth. But evidence is mounting that the asteroid strike might have just been the final killing blow. The previous 500,000 years were unpleasant too, with multiple meteor strikes, severe volcanism, and rapid climate change.

Read the full blog entry (http://www.universetoday.com/2006/10/25/it-took-more-than-an-asteroid-to-kill-the-dinosaurs/)

gazelle1978
2006-Oct-26, 12:42 PM
I remember hearing a theory about this:
A brown dwarf is in a Hayley's Comet style highly eccentric orbit ocassionaly coming close to the sun causing the randomisation of the astroids orbits. As a conquence there were recurring times when the earth had to "clear out it's orbit" again i.e. the Cretaceous and Permian mass extinctions were linked.

Rob1ooo1oo
2006-Oct-26, 02:17 PM
There is also the one of the solar system oscillate through the main disc of the galaxy, so going through "thick patches" every XXmillion years (forgot the figure). Causing gravitational tugs which fling debris into the solar system.

Alex0703
2006-Oct-26, 02:34 PM
I am thinking if a giant asteroid hit the ocean 65 million years ago. Since the ocean covered roughly 70% of the earth's surface even 65 million years ago, the probability that it hit the ocean is much easier than it hit on the ground.

It might sound like if it hit the ocean, it would not have generated that severe temperature effect. In fact, i have watched a science TV program. it has showed a team of researchers examinating the effect of shooting a bullet into water with a very high-tech camera, which could take a snapshot every .01 sec. The result was amazing. The pictures showed that the water around the bullet vaporized immediately right after the bullet hit the water.

Imagining that bullet was a giant asteroid moving at the speed of several hundred miles per sec, it would have vaporized the water around it instantly and would have created a crater on the ocean bed. Thereotically, whether an asteroid hit on the ground or into the ocean, it still will deliver the same amount of energy to earth, mostly from kinetic to thermal energy. If this is really the case, the asteroid would rise the earth's atmoshperic temperature rapidly, distorted the earth's core, caused earthquakes and volcanism both on ground and under water, hurricane and water flood. This critical condition would have reduced the number of lives by a large amount. And then, in 500,000 years, it was followed with multiple meteor strikes and the asteroid that struck Yucatan peninsula, that brought the dinosaur survivors to extinction.

If an asteroid really struck the ocean, it will be very difficult for researchers to discover the crater. And if the crater really exists, it would have been filled and covered up with sand and soil by the non-stop ocean current. This is just my sudden thought, without any data/research support.

Mayonaze
2006-Oct-26, 05:13 PM
Gazelle is referring to the Nemesis Theory. I thought that theory had been debunked years ago but apparently it is still alive. Here's a link to a short paper on the subject http://muller.lbl.gov/pages/lbl-nem.htm

GBendt
2006-Oct-27, 01:01 PM
Hi,
I think the data on which the statement that the Chicxulub impact was not resposible for mass extinction of species including the dinosaurs is based is a little thin.
Firstly, I recall various investigations that were taken out worldwide between 1980 and 1995 on soil samples from above and below the iridium layer, which said that in these samples the microfossil composition was a quite different one below the iridium-rich layer compared to the one above.

Further, the age of a sediment layer is difficult to investigate, as the microfossils do not show a certificate of birth. You can only guess, as the numbers of various species in a sediment layer change not only with time, but also with the location. Thus you can only pinpoint the age with a careful accuracy of a million years.

I think some more investigations on this matter have to be carried out with care.

The collision that produced the Chicxulub crater took place in an area with a limestone bedrock of many miles thickness. From the size if the crater we know that some 300.000 cubic kilometres of bedrock (mostly limestone) where evaporated by the impact whithin seconds and exploded into the atmosphere. This is 800.000 billion tons of tock, blown up in an instant by an energy of 10 million billion gigajoule, at a heat of 60.000 centigrades. Enough to kill almost everything. Fire rained down everywhere over the world, everything went up in flames.
The resulting rise of the atmospheric carbon dioxide raised the wolrdwide earth temperature all of a sudden by more than 8 centigrades.

Compared to that, the Decca volcanism took place for many hundreds of thousands of years. It resulted in creating vast and thick layers of basalt rock in an area we now call India. It was not a short catastrophic event. As there was time to adapt, life-forms were able to adapt to this situation.

The Hawaian archipelago consist of basalt, too. It was created within a timespan that was about as long as that in which the decca traps were created, and produced a comparable amount of basalt (some 1.9 million billion tons). However, nobody assumes that the creation of the Hawaian islands may have caused a worldwide mass extinction...

Regards,

Günther

jlhredshift
2006-Oct-27, 01:13 PM
Though Muller et al supposed a dwarf star, what about Xenia?

John Mendenhall
2006-Oct-27, 05:46 PM
All right, folks, let’s open the can of worms:

1. I have no idea why people have so much trouble with Chicxulub. As an explanation it is parsimonious. One big impact and bang, the Cretaceous is over. The radius of the fireball probably reached to the Carolinas. There is tsunami debris 200 miles inland in Texas. There is a worldwide layer of clay at the impact time. There are no dinosaurs above the clay. There are plenty of dinosaurs below the clay. And on, and on.
2. Let’s offer another more general idea. The Deccan Traps are approximately at the antipodal point for Chicxulub, allowing for continental drift (please, let’s not quibble about the antipodal location of Chicxulub 65 million years ago, 10 to 20 degrees is close enough). How about if big impacts on Earth pop a plume off the lower mantle on the other (antipodal) side? Anybody want to examine igneous provinces and check for antipodal impact craters? How about Hawaii, and Iceland, and Yellowstone? Olympus Mons and the Tharsis volcanoes on Mars? Venus? Something resurfaces Venus every once in awhile.
3. jlhredhift’s comment about Xenia is an interesting idea. We still have little knowledge of the Kuiper belt objects.

In summary, I think Occam’s razor wins on this one. The simplest explanation is probably the correct one.

(If you haven't read GBendt's comments above, please do, there are many good points).

jseefcoot
2006-Oct-27, 06:16 PM
Personally, I don't think any mass extinction can be attributed to a single cataclysmic event. I think that many factors were likely to have played a role, and while I do think that this asteroid impact was the the most severe factor, I am willing to bet there are others.

There are undoubtedly some places of the globe that were not as affected as others. I sometimes wonder at how people assume that the entire globe became so many degrees hotter. Maybe on average. I don't think the temperature would have been uniformly distributed then, just as global temperatures are not uniform now. I think it is just as likely that in the area of the impact, temperatures were extremely severe, but on the other side of the globe, they weren't near so bad. This isn't to say that the impact led to an extinction, but it was more of a catlayst, in my mind, then the actual cause.

This does seem to be the best theory to fit the facts, but there are enough holes to lead me to think that there were other factors.

GOURDHEAD
2006-Oct-28, 02:45 AM
And yet turtles, crocodilians, birds, and our ancestral mammals survived while dinosaurs, pteranodons and mosasaurs did not--a bit of a mystery eh wot.

greenfeather
2006-Oct-28, 03:58 AM
All right, folks, let’s open the can of worms:

The Deccan Traps are approximately at the antipodal point for Chicxulub, allowing for continental drift (please, let’s not quibble about the antipodal location of Chicxulub 65 million years ago, 10 to 20 degrees is close enough).

YES!! And the Siberian Traps are antipodal to the huge crater they recently found in Antarctica.


How about if big impacts on Earth pop a plume off the lower mantle on the other (antipodal) side? Anybody want to examine igneous provinces and check for antipodal impact craters? How about Hawaii, and Iceland, and Yellowstone? Olympus Mons and the Tharsis volcanoes on Mars? Venus? Something resurfaces Venus every once in awhile.

THANK YOU. Finally someone said what seems obvious to me. The meteor strikes cause the volcanism. First came the Big Rock. It put great big cracks all around the Earth's crust. As a result, lots of fire & lava spurted out of the Siberian Traps, the Deccan Traps, what have you. The resulting nasty gases caused the global warming, the anoxia & the extinction.

I have been reading so many books & articles about the extinctions and they all hesitate to make these connections. I wonder why? They dance around it. Just today there was a link from msnbc.com science that claimed "it took more than a meteor to kill the dinosaurs. There were also volcanoes & sglobal warming. Oh, and the Permian Extinction was caused by not enough oxygen in the air." The way they state these facts reads like "well, all these things just happened to occur at the same time."

"The Earth got sick" was how they put it. That's nonsense to me! Do massive volcanism and global warming just "happen" at random times? I have trouble with that. I find it much easier to believe that an impact caused these things.

If a window is broken, I find it easier to believe a baseball hit it than that it just "happened" to break, especially when a baseball has been found nearby.

Of course, I have cracks in all my windows, and there are no baseballs around, so it's a bad example. Then again, my house is 100 years old. I guess continental drift did it.

greenfeather
2006-Oct-28, 04:03 AM
And yet turtles, crocodilians, birds, and our ancestral mammals survived while dinosaurs, pteranodons and mosasaurs did not--a bit of a mystery eh wot.

If you're speculating on a sort of 'impact winter' that killed most plant life: Turtles were able to crawl into the mud and avoid what was happening overhead. They could probably find worms to eat, and they have a slow metabolism. The mammals of that time were tiny scurrying things, who probably could find a lot of carrion to scavenge on. Birds could fly away to a better area. However, a larger creature such as a dinosaur would have much more trouble finding food. The large saurians were probably at the top of the food chain. Even today the largest mammals are the most vulnerable to human-caused changes.

Essel
2006-Oct-28, 11:43 AM
While scanning the Google Earth, I possiby found an Impact crater in a place called Junagdh in India. This should be some 50-80 Kms across. Pls have a look and comment....

John Mendenhall
2006-Oct-28, 01:03 PM
THANK YOU, Greenfeather.

I forgot to mention, with respect to large impacts and antipodal disturbances, the very large multi ringed impact basin on the Moon that is not quite visible from Earth, has jumbled, chaotic, mountainous terrain associated at the antipodal point. I have seen speculation that the surface waves, spreading like ripples in a pond, traveled around the Moon and combined constructively on the opposite side, totally disrupting the surface.

Wow!

With respect to the fauna that survived K-T, I have seen 10 kilograms (22 pounds) as the upper limit for land animal size. For reference, that’s about the size of a healthy groundhog – an animal notorious for its burrows.

Loved your continental drift/cracked windows theory. My business partner (she is the originator of the Theory of Accumulating Gravity, about which the less said the better), has already accepted your idea.

Now it’s off to look at India.

GOURDHEAD
2006-Oct-28, 01:42 PM
Wouldn't the antipode of any point in the northern hemisphere have to be located in the southern hemisphere?

GBendt
2006-Oct-28, 03:06 PM
Hi,
An impact of the type which created the Chicxulub crater released an energy equivalent to that of several hundred million megaton hydrogen bombs, and this within less than a second.
The resulting explosion converted 800.000 billion tons of rock into glowing dust and gravel and blew it into the air and beyond, in a wave of fire. The momentum resulting from the explosion must have caused enormous seismic waves which travelled through the body of our planet, releasing a lot of tension that had built up between the plates of the crust before, and this altogether must have caused enormous earthquakes and extreme volcanic activities.
Volcanic eruptions, however, cannot go on forever and ever, as the supply of gas the pressure of which drives the eruptions is limited.

The world must have been a place of utmost horror at that time. A real armageddon. Numerous species were wiped out in that environment, and so many individuals died that almost all species must have come close to extinction.
But a few small or frugal ones managed to survive somehow, perhaps hidden somewhere in a deep hole with a nice supply of food, or sheltered in a muddy swampy area, or in a remote sheltered and fertile valley, far from the eruptions, with some supplies of fresh rock water and some roots to gnaw.
And fortunately, our ancestors were among them. As the sky became clear again and the first leaves appeared after the fresh rain, the world was theirs.

Regards,

Günther

greenfeather
2006-Oct-29, 12:52 PM
Hi,
An impact of the type which created the Chicxulub crater released an energy equivalent to that of several hundred million megaton hydrogen bombs, and this within less than a second.
The resulting explosion converted 800.000 billion tons of rock into glowing dust and gravel and blew it into the air and beyond, in a wave of fire. The momentum resulting from the explosion must have caused enormous seismic waves which travelled through the body of our planet, releasing a lot of tension that had built up between the plates of the crust before, and this altogether must have caused enormous earthquakes and extreme volcanic activities.

It works for me. I don't understand why authors such as Bennett "When Life Nearly Died" and Ward "Gorgon" brush this aside. They see no reason why an impact would lead to volcanism. These guys both write extensively about the volcanism, oxygen loss, global warming etc. as if these things just "happen" by themselves.

Like, why is Mars lopsided? Could it be a giant thingy crashed into it, forcing magma out the other side in the solar system's largest volcano?


Volcanic eruptions, however, cannot go on forever and ever, as the supply of gas the pressure of which drives the eruptions is limited.


Well, I wonder why the Siberian Traps flood basalt eruptions went on for millions & millions of years. Supposedly enough to bury the whole Earth 10 ft deep in lava. Kind of hard to imagine. Where did all of that come from and wouldn't the Earth hollow itself out?

damienpaul
2006-Oct-30, 10:46 AM
Perhaps as mentioned, a combination of events such as the Chixculub Crater, mass volcanism (Deccan Traps (http://volcano.und.edu/vwdocs/volc_images/europe_west_asia/india/deccan.html) for example) not necessarily linked - but resulting in a definite change in climatic - ecological systems.

Also, I recall reading somewhere that the dinosaurs were already in decline before these events

John Mendenhall
2006-Oct-30, 06:10 PM
Wouldn't the antipode of any point in the northern hemisphere have to be located in the southern hemisphere?

Yes. For the possible crater in India referred to by Essel, the antipodal point is

Lat Long
Deg Min Sec Hemi Deg Min Sec Hemi
Loc 21 31 19.07 N 70 32 47.67 E
A-P 21 31 19.07 S 110 28 12.33 W

and Google Earth will take "21 31 S 110 28 W" as Go To inputs just fine. And I'm not going to tell you what's within 5 degrees SSE of there at present, you'll have to look for yourself.

greenfeather
2006-Oct-30, 11:36 PM
Also, I recall reading somewhere that the dinosaurs were already in decline before these events

For one thing, some of those dinosaurs were so damn big, they must have been running out of food. A large animal is always fewer in number, so the larger the animal, the less there were.

Anyone ever see WALKING WITH DINOSAURS? I got the DVD! I can't imagine how creatures that big ever evolved... did something happen to lessen Earth's gravity? (dumb question, but still. There has to be a limit to how big a creature can get.)

John Mendenhall
2006-Oct-31, 05:56 PM
Wouldn't the antipode of any point in the northern hemisphere have to be located in the southern hemisphere?

At the address below there is a wonderful map of the continents at the time of the K-T impact (note the antipodal location):

http://www.scotese.com/K/t.htm

Below for the geology of India (note the proposal that India ran over the Reunion plume):

http://en.wikipedia.org/wiki/Geology_of_India#The_Deccan_Traps

And for the Deccan Traps:

http://en.wikipedia.org/wiki/Image:India-geology-map.png

It doesn’t get any better, folks!

Come on, somebody else do Manicouagan!

ToSeek
2006-Oct-31, 08:23 PM
Margiani's ATM "cosmogeology" post (and one response) moved to this thread. (http://www.bautforum.com/showthread.php?t=48781)

BigDon
2006-Oct-31, 11:05 PM
John M. Another thing that gets lost in the details is the dino killer came in at a very low angle from amost due south. Wasn't a straight-in equatorial hit. Thats what emptied the Carribean into Texas. (Can't cite, read it in a book.) I saw those 120 foot long, 30 foot wide chunks of oceanic basalt that got washed 200 miles into Texas.

Six miles across! What always gets me is when they say that after it burrowed a mile into the Earth it was still five miles into the atmosphere!

John Mendenhall
2006-Nov-01, 02:34 PM
BigDon - I hadn't heard that. Anybody know more? Where's the basalt? I want to see it, even if requires a trip to Texas!

Interesting point here. We live 10 miles from a place called 'Iron Hill', which has, guess what, some old iron mines. The geologists' explanation is 'maybe it's an ancient impact site'. The surrounding geology is sedimentary coastal plain. And the big buried crater at the mouth of the Chesapeake Bay is only 150 miles away. Look around where you live. How far away is the closest identified impact crater?

GBendt
2006-Nov-02, 12:26 AM
Hi,
Dinosaurs lived on earth for more than 130 million years. This is twice the time that passed since the "extinction" of the dinosaurs 65 million years ago.
The species of dinosaurs have changed with time. Such, giants like Brontosaurus, Brachiosaurus and Diplodocus were no contemporaries of T. Rex ,or Velociraptor. These huge, long-necked giants lived 60 millon years before T.Rex, and became extinct long before the cretaceous period. In fact, T. Rex is so far away from them at his time than T. Rex is from our days.

Research in paleoclimatics revealed that during the cretaceous period, the average temperature on earth was 12° C warmer than it is today, and that the oxygen content in the air was 35% instead of the 20% we have today. Further, the air was denser, such it was easier for large flying dinosaurs like Pteranodon to keep flying. Breathing was a lot more effective, as each breath brought in a lot more oxygen than a breath does, taken today, and in a permanently warm climate there is no need to spend energy to keep the body warm and moving. That is why dinosaurs could thrive, and grow to such sizes.
The world was quite a different one in these days. The climate we have today would have been a handicap for dinosaurs, such it isn´t a miracle that now they are extinct.

The volcanism which created th Decca Traps did this within several millions of years in a typical "hotspot"-event. It took it more than three million years to produce 800.000 billion tons of lava. That is a lot, but the Chicxulub crater blew up about the same amount of hot debris within a mere second. If you look at an event, you must regard the time scale of it, too.

Dinosaurs did not die all within the same day. Some people assume that they were not killed altogether, and that some still live today. They are called "Birds". Some dinosaur fossils revealed that these dinosaurs were feathered when alive.

Regards,

Günther

greenfeather
2006-Nov-02, 12:44 AM
Dinosaurs did not die all within the same day.

astrobio.net has an article "Dinosaur Era Ended Instantly"
Terrestrial Origins Summary (May 29, 2004): The latest research findings corroborate evidence that the dinosaurs died almost instantaneously, and not, as some claim, survived the global impact disaster for thousands or even hundreds of thousands of years.

This article is 2 years old. It says The "heat pulse" caused by re-entering ejected matter would have reached around the globe, igniting fires and burning up all terrestrial organisms not sheltered in burrows or in water, he said.

"The kinetic energy of the ejected matter would have dissipated as heat in the upper atmosphere during re-entry, enough heat to make the normally blue sky turn red-hot for hours," said Robertson. Scientists have speculated for more than a decade that the entire surface of the Earth below would have been baked by the equivalent of a global oven set on broil."

It also mentions that the organisms that survived were " the vertebrates that could burrow in holes or shelter in water -- mammals, birds, crocodilians, snakes, lizards, turtles and amphibians"

However, astrobio.net has also had articles about how the comet wasn't responsible for the extinction. So they are changing their minds every day!!

greenfeather
2006-Nov-02, 12:57 AM
Sick Earth?

quoted from astrobio.net

"Terrestrial Climate History Summary (Oct 28, 2006): What caused the Permian-Triassic extinction, the largest mass extinction in Earth's history? The most likely explanation for the disappearance of up to 90 percent of species 250 million years ago, said David Bottjer of the University of Southern California, is that "the earth got sick." "

This is what I call Bad Science!!!
The article says that the normal circulation patterns of the oceans were disrupted and that caused the extinction. He doesnt' say what caused this to happen. Um, what causes a planet to 'get sick"? Are there interstellar germs floating around? This is like saying "the patient died because his heart stopped beating." In fact, saying that the extinction was caused because the Earth got sick is almost as unscientific as saying it was a result of a magic spell!!

Then the article says "Nor does the cause appear to have been a meteorite strike". Why not? Has Bottjer proved that the huge crater in Antarctica isn't linked to the end-Permian? You can't just say "it doesn't appear to be so." You have to present some plausible reason why.

There sure is a lot of baloney floating around about the Permian. I wonder if it isn't becoming a political hot-potato. Those who want to minimize the dangers of global warming are going to point to a giant comet and say "it can't happen again". While those who fear the effects ot global warming could say 'you never know... those methane deposits could melt and it could all happen again."

Personally I do have a bias. I would rather learn that a 90 percent mass extinction was caused by extraterrestrial impact, than to learn such things could happen anytime just because Earth gets sick and catches a cold. Geez, I sure hope Earth is taking Her vitamins!

And yes, I do think global warming is a serious threat, along with all the other things humans are doing. I really want to know why we don't have an Earth Program like we had a Space Program. But that's probably for another thread.

John Mendenhall
2006-Nov-02, 04:17 PM
"The kinetic energy of the ejected matter would have dissipated as heat in the upper atmosphere during re-entry, enough heat to make the normally blue sky turn red-hot for hours," said Robertson.

If you have any doubts about this, review the films of the Shoemaker-Levy impacts on Jupiter.

Delvo
2006-Nov-02, 06:13 PM
To see what they're talking about with the extinctions being caused by life on Earth itself, see Scientific American from this month or one of the last few months. The basic idea has to do with a couple of classes of microbes that are known to exist, but only in certain locations usually far underwater where they normally don't have anything to do with us: microbes that consume or produce hydrogen sulfide. They can't live in an oxygen-rich atmosphere or water with oxygen dissolved in it. In the oceans, oxygen is dissovled in the upper regions, but these things live farther down where sulfur or hydrogen sulfide is the predominant gas dissolved in the water. None of that is new or theoretical, it's just the background info. The theory that's getting articles written about it lately is that the transition zone where it goes from one to the other can move up or down over the years, and if it moves up all the way to the surface, then instead of oxygen going into the water from the air, you get hydrogen sulfide going into the air from the water... lots and lots of it. A mass extinction then results from the poisoning of the atmoshpere by the ocean(s) and other effects such as heavy sulfuric-acid rain on the land and a drop in atmospheric oxygen levels.

And this can be caused by a steep rise in the planet's temperature, or by a comet/asteroid impact, but doesn't necessairly need to, which answers the conundrum of some extinctions appearing to be connected with obvious impacts but some appearing to happen at times when there's no sign of an impact.

John Mendenhall
2006-Nov-02, 08:26 PM
. . . you get hydrogen sulfide going into the air from the water... lots and lots of it. A mass extinction then results from the poisoning of the atmosphere by the ocean(s) and other effects such as heavy sulfuric-acid rain on the land and a drop in atmospheric oxygen levels.

And this can be caused by a steep rise in the planet's temperature, or by a comet/asteroid impact, but doesn't necessarily need to, which answers the conundrum of some extinctions appearing to be connected with obvious impacts but some appearing to happen at times when there's no sign of an impact.

Interesting, but complicated. For the K-T, K.I.S.S. applies. Keep It Silly Simple. Whacko. Global furnace from out of the sky. Everything on the surface dies. Seeds and burrowing animals survive. Birds make it, for unclear reasons. (Antarctica, maybe? Or I think there are birds that nest in burrows, on predatorless islands.)

Your turn, Greenfeather.

GBendt, do you have any references for oxygen levels and atmospheric pressure?

greenfeather
2006-Nov-03, 12:45 AM
Interesting, but complicated. For the K-T, K.I.S.S. applies. Keep It Silly Simple. Whacko. Global furnace from out of the sky. Everything on the surface dies. Seeds and burrowing animals survive. Birds make it, for unclear reasons. (Antarctica, maybe? Or I think there are birds that nest in burrows, on predatorless islands.)

Your turn, Greenfeather.

Yayy! I love Tag Team.
Yeah, I was about to mention Occam & his Razor myself!! There was a time when it seemed outlandish that a comet could fall out of the sky & destroy everything... but anymore it looks as if it happens all the time in the universe. Look at all the other planets & moons!!! Every one that doesn't have active geology is just a target, covered with craters on top of more craters.

So yeah, all the above mentioned effects were probably involved in a mass extinction & disruption of the Earth's ecology... but what could cause such a big disruption in the first place? I couldn't see anything terrestrial, at least not till Humans came along, capable of stripping the Earth's surface almost bare of life. Only something vast and astronomical in scope...if not an impact, then something capable of disrupting Earth's orbit (okay, that would also probably be a large planetoid or other rockball).
Earth seems to be fairly resilient. The universe, on the other hand, is a dangerous place!!!

So an impact seems the simplest explanation. And the scientists who reject that explanation seem to do it on personal or esthetic grounds. Like Erwin, who seems to say "it would be boring if all the extinctions happened exactly the same way."

I don't think that's very scientific myself. And I'm not even a scientist.

greenfeather
2006-Nov-03, 01:53 AM
microbes that consume or produce hydrogen sulfide. The theory that's getting articles written about it lately is that the transition zone where it goes from one to the other can move up or down over the years, and if it moves up all the way to the surface, then instead of oxygen going into the water from the air, you get hydrogen sulfide going into the air from the water... lots and lots of it. A mass extinction then results from the poisoning of the atmoshpere by the ocean(s) and other effects such as heavy sulfuric-acid rain on the land and a drop in atmospheric oxygen levels.

And this can be caused by a steep rise in the planet's temperature, or by a comet/asteroid impact,

Would these be the extremophile bacteria that live off the "black smoker" undersea volcanic vents?

A few questions about this theory. What would cause the transition zone to move up to the surface? You're talking about a catastrophic change in sea level. Which seems to me an effect rather than a cause. Yes, there would be major earthquakes & tsunamis --as results of an impact.

Wouldn't the hydrogen sulfide bacteria die when they get in contact with oxygen from the surface? Wouldn't volcanoes be as likely a source of hydrogen sulfide?

Margiani
2006-Nov-03, 01:45 PM
[QUOTE=A mass extinction then results from the poisoning of the atmoshpere by the ocean(s) and other effects such as heavy sulfuric-acid rain on the land and a drop in atmospheric oxygen levels.

And this can be caused by a steep rise in the planet's temperature, [/QUOTE]

You are absolutely right. mass extinction on the land was caused huge volcanic poisonous and suffocating gasses and sulfuric-acid raines suffocated and died almost all living beings, on the land. But what is the reason mass extinction into seas and oceans?

Blob
2006-Nov-03, 03:11 PM
I possiby found an Impact crater

Hum,
it's an interesting feature.
it looks to me like a volcanic dome that was created 70 million years ago.
i have included an attachment with the vertical exaggerated x5 to show the dome.

Latitude: 21.51475 Longitude: 70.49133

Margiani
2006-Nov-03, 05:45 PM
To see what they're talking about with the extinctions being caused by life on Earth itself, see Scientific American from this month or one of the last few months. The basic idea has to do with a couple of classes of microbes that are known to exist, but only in certain locations usually far underwater where they normally don't have anything to do with us: microbes that consume or produce hydrogen sulfide. They can't live in an oxygen-rich atmosphere or water with oxygen dissolved in it. In the oceans, oxygen is dissovled in the upper regions, but these things live farther down where sulfur or hydrogen sulfide is the predominant gas dissolved in the water. None of that is new or theoretical, it's just the background info. The theory that's getting articles written about it lately is that the transition zone where it goes from one to the other can move up or down over the years, and if it moves up all the way to the surface, then instead of oxygen going into the water from the air, you get hydrogen sulfide going into the air from the water... lots and lots of it. A mass extinction then results from the poisoning of the atmoshpere by the ocean(s) and other effects such as heavy sulfuric-acid rain on the land and a drop in atmospheric oxygen levels.

And this can be caused by a steep rise in the planet's temperature, or by a comet/asteroid impact, but doesn't necessairly need to, which answers the conundrum of some extinctions appearing to be connected with obvious impacts but some appearing to happen at times when there's no sign of an impact.

If you want to understand what happened at the K/T boundary please read my first topic in the my thread.
-against the mainstream-Cosmogeology - #1

GBendt
2006-Nov-08, 11:55 PM
Hi John,

There are a couple of scientific investigations that were carried out to explain how flying dinosaurs with wings spanning up to 15 m (Quetzalcoatlus) were able to fly. 15 m is more than four times the wing span of an albatros.
Robert Berner found clues that the content of oxygen was higher in the carboniferous (35%) and the cretaceous period (28%) (Science, Vol. 287, P. 1630-1633). The zoologist Robert Dudley (Journal of Experimental Biology Vol. 201, p. 1043) found that a higher content in oxygen as well as a higher density of the air in the cretaceous period were essential to bring the giant flying dinosaurs up in the air, as nowaday´s air density and oxygen concentration limits the maximum size and weight of flying animals to that of an albatros.
Higher content of oxygen in the atmosphere means a respective rise in atmospheric pressure and density: The denser the air, the easier it becomes to fly with wings, and the higher the concentration of oxygen, the more effective every breath becomes you take.

Regards,

Günther

PhantomWolf
2006-Nov-09, 03:20 AM
Okay I admit it, it was me, and they was mighty tasty too. ;)

GOURDHEAD
2006-Nov-09, 02:00 PM
Okay I admit it, it was me, and they was mighty tasty too. ;)More likely your blood sucking ancestors and their symbionts.

GBendt
2006-Nov-09, 11:49 PM
Hi John,

Some scientific investigations have been carried out to find clues why the huge flying dinosaurs of the cretaceous period were able to fly. The flying dinosaur Quetzalcoatlus, for instance, had a wingspan of more than 15 m, this is more than four times the wingspan of an albatros. How could such large flying dinosaurs manage to fly? Why have flying birds never grown to a comparable size?
The zoologist Robert Dudley found that in an air with the composition and density of nowaday´s air, Quetzalcoatlus was unable not fly. Thus, a higher content of oxygen and higher air density must have been essential for these giants to make it up into the air, and keep them in flight (Journal of Experimental Biology Vol. 201, p. 1043). Robert Berner from Yale University found that air bubbles in cretaceous amber contained 30% oxygen (Science, Vol.238, P. 890).
If more oxygen gets into the atmosphere, the mass of the atmosphere rises and the atmosphere becomes denser. The denser the atmosphere, the easier becomes flying. The more oxygen is in the atmosphere, the more effective becomes breathing: you don´t get out of breath any more.

The content of oxygen in the atmosphere is the result of oxygen production by plants and algae, and oxygen consumption by animals, fire and oxydating processes. The oxygen production by plants and algae is higher in a warm and damp climate. In the cretaceous period, the climate was warm. By examining the relative contents of isotops of oxygen in worm shells from cretaceous seabeds, a team of scientists around Dr. Thomas Steuber from the German Ruhr University found that the yearly average water temperature was 20°C at the north pole (!) some 80 million years ago, while ar the same time the yearly average water temperature at the equator was 38°C. Thus, Antarctica must have been a warm place too, covered with dense forests. The whole world may have been green and flourishing 12 months a year; as the years had no winter. Plants then may have produced a lot more oxygen than they can do today, and also plenty of food on which small as well as gigantic herbivorous animals fed.

Regards,

Günther

closetgeek
2006-Nov-12, 10:03 PM
I never fully understand how we can have so many exacts (or relative exacts) in the study of dinosaurs. I have a hard time believing the impact theories because of the many species that have survived the ages. My daughter is more of a dinasour fanatic than I, but I watch programs with her, and it depicts sharks that lived in that era, as well as primates, etc. What kind of impact selectively killed an entire array of one type of species, but left so many intact? There are relatives of dinosaurs that exist today, doesn't that imply that some had to have survived to evolve? Am I over-simplifying thesubject?



How did the dinosaurs die? It's a question scientists have been trying to figure out since their fossils were first discovered. Most believe that it was a giant asteroid that stuck the Yucatan peninsula 65 million years ago, and ended the dinosaurs' reign on Earth. But evidence is mounting that the asteroid strike might have just been the final killing blow. The previous 500,000 years were unpleasant too, with multiple meteor strikes, severe volcanism, and rapid climate change.

Read the full blog entry (http://www.universetoday.com/2006/10/25/it-took-more-than-an-asteroid-to-kill-the-dinosaurs/)

Blob
2006-Nov-13, 03:06 PM
German palaeontologists have produced new evidence to show that dinosaurs became extinct due to a meteor that is believed to have hit India rather than the one held responsible till now.
The experts insist that a mysterious meteor or comet must have done the deadly deed - long after the notorious Yucatan meteor that has hitherto been blamed.

Read more (http://www.indiaenews.com/europe/20061113/28517.htm)

hhEb09'1
2006-Nov-13, 04:47 PM
It doesn’t get any better, folks!

Come on, somebody else do Manicouagan!The idea about impacts and antipodal lava flows actually made it into Time magazine (Jan. 9, 1995). Michael Rampino has done a lot of work on mapping the impacts and flows, and checking the antipodal character of the maps.
They see no reason why an impact would lead to volcanism.It's a large problem. I had a poster next to one by Rampino at the December 1993 American Geophysical Union meeting, and I got to listen while Rampino's student defended their attempt at a mechanism to Vincent Courtillot--one of the main proponents of volcanism in the extinction (he had the counterpoint article to Walter Alvarez's 1990 Scientific American article defending his impact thesis). He was not convinced. It's not an easy thing to solve at all.

greenfeather
2006-Nov-13, 09:42 PM
I don't know if links to astrobio.net work, but I read an article there called "Lord of Gondwanaland". It's about Peter Ward's book "The Life and Death of Planet Earth." But mostly it is a vignette about the Gorgon, the cynodon, and other life (and death) during the Permian Extinction.

I must admit the subject holds a morbid fascination.
Then the other day I was browsing in the bookstore, where Ward has written a book called "Out of Thin Air". It is about how the oxygen levels have fluctuated over the millenia and how they have affected evolution. Very interesting looking book--sure wish I could buy a used copy from Amazon!

Anyway, Ward continues to ascribe the Permian extinction to "lowered oxygen levels" without speculating as to how the levels could get so low. Does the Earth just have its ups & downs like a woman with PMS? His comments on the impact theory: he thinks it is mostly for the general public and for sensationalist journalists--serious scientists don't believe in it. Plus, the Becker "team" is too dogmatic about it, so he doesn't get along with them. For these reasons, he generally discounts the possibility of an impact.

That's very irritating to me! It's not scientific at all. I realize that the "permian question" has become a big food-fight with scientists. But since they discovered a large impact crater in Antarctica, I have heard no comments on it from the "non-impact" camp; in fact, I've heard nothing at all! I wonder if that turned out to be a fake. If not, Ward needs to address the issue of "maybe the 02 levels got out of whack because a big impactor came and set fire to the atmosphere and cracked the Earth". Eh? Yes or no?

http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=386&mode=thread&order=0&thold=0

hhEb09'1
2006-Nov-13, 10:03 PM
[/url][url=http://eospso.gsfc.nasa.gov/]Earth Observing System (If there's a SPACE Program, why isn't there an EARTH program?)

joedoe
2006-Nov-14, 02:15 AM
Closetgeek
I never fully understand how we can have so many exacts (or relative exacts) in the study of dinosaurs. I have a hard time believing the impact theories because of the many species that have survived the ages. My daughter is more of a dinasour fanatic than I, but I watch programs with her, and it depicts sharks that lived in that era, as well as primates, etc. What kind of impact selectively killed an entire array of one type of species, but left so many intact? There are relatives of dinosaurs that exist today, doesn't that imply that some had to have survived to evolve? Am I over-simplifying the subject?

Interested me too, how can a Quetzalcoatlus fly when it must have been very heavy, and how does a Brontosaurus. Height:. 35 ft. Weight:. 32 tons. Length:. 25 m (82 ft). move at all on land?

I suspect it was not an impact as such, but gravity increasing in strength. After all, the natural selection was for over all smaller body sizes. And what ever caused the gravity to increase also modified/upset our weather, land and ocean system dynamics. :neutral:

Do we have any proof G has been more or less constant since before the Saurs up till now? We seem to be discovering more and more about the way high energy particles from the Sun and outer space interact and modify our weather (and it's effect on bio-systems below), there might be a causal link between all these factors that led to large land animals dieing off :eh:

But I spose if we all believe that a massive global impact is the cause and keep telling our kids the same then that’s all it could have been then. :cry:

Still there great shows to watch and they still must have been impressive to see "in the flesh". :D


:)

Three Of Five
2006-Nov-16, 04:33 PM
Why do you create such complex theories to explain extinctions? What theory would a future human conceive about our present day extinction rate? In geologic terms, it's a mass extinction what we are doing to our planet and the cause was internal. We don't have to blame white dwarfs or some other esoteric explanations, the causes can be right here.

That doesn't mean that there aren't meteor impacts. Just lock at an earth globe for mexican gulf? Look carefully? Doens't it look like a big crater ?

The meteor fall in the ocean may explain the catastrofic end os last ice age, tons of vaporised water in the atmosfere, quick rise of temperatures accelerated the ice melt and the water vapor caused torrential rains lasting for months! It's almost certain that a pre-ice age civilization existed. Modern humans have arised for 50 000 years and that's an accepted fact. Look again to the earth globe and image the ice sheets far south as Italy. There are two areas that could sustain civilization, africa and the area around indonesia, wich was dry earth before the sea level rise. So the human species had more than time to create one or more civilizations, they had thousands of years. If the ice age climate were ao harsh, how could we have evolved in such environment?

Three Of Five
2006-Nov-16, 04:39 PM
G constant doesn't change. If G decreases than the planet size would increase, cracks would appear and all water would fill those cracks. Oceans would disappear. If G constant increase then the planet would shrink, volcanic eruptions would arise and sea level would rise until no dry land would be left. That's not an acceptable theory.

dinosaujrs
2006-Nov-17, 11:51 AM
It took more than an asteroid to kill the dinosaujrs, and perhaps it was that they went blind due to the change in sunlight which prevented them from finding a mate. It is my opinion that the lack of sunlight due to the catalysmic fallout of global dust wiped out the majority of the species. The species left might have been birds, but it was a mass extinction. Why did it happen, and why am I so intrested?

antoniseb
2006-Nov-17, 12:22 PM
Why did it happen, and why am I so intrested?

I don't know why you are so interested, but welcome to the BAUT forum.

3rdvogon
2006-Nov-17, 03:21 PM
Closetgeek

Interested me too, how can a Quetzalcoatlus fly when it must have been very heavy, and how does a Brontosaurus. Height:. 35 ft. Weight:. 32 tons. Length:. 25 m (82 ft). move at all on land?
:)


Yes the points you make have puzzled me for a long time also.

Now of course any severe environmental change be it a sudden catastrophic event or a steady build up increasing difficulty is going to put life under stress. In all cases will tend to be the larger animals which will suffer the most in such conditions.

They tend to live longer and have longer breeding and growth cycles.
There are always fewer of them for a given amount of territory because each requires a lot of real estate to support that applies to the plant eaters and those that prey on them.
Then as has already been mentioned it is more difficult for them to shelter themselves from adverse conditions.

Now all of the above factors works as an explanation as to why T Rex and the other giants did not survive beyond the KT boundary. That however only offeres us a partial explanation.

Many of the dinosaurs alive at the same time as T Rex were small (chicken sized) so why did not of them survive beyond the KT boundary. They were probably warm blooded like mammals and birds. They were small enough to find places to shelter.

In fact I cannot understand that if other small forms of life on land survived Birds, Mammals and Reptiles etc then why not these small dinosaurs? Now one explanation given is that they evolved into birds. The trouble is by that time birds had already evolved before this event. The birds we have today are more likely to have evolved from those early birds than from other small dinosaurs. So if there were already birds flying before the KT boundary and at the same time small non-flying dinosaurs then why did one become extinct and not the other. I feel that the answers I have heard so far on this matter don't seem to stack up.

After conditions improved again there was an evolutionary explosion. From what I have read the mammals were actually not the first ones to fully exploit this. Instead reptiles and birds took the early lead. Why could not have some of these smaller dinosaurs have survived the catastrophe and also joined in that recovery race. They might never have evolved into the giants of the earlier periods but they should have been able to pose a good challenge to the birds and reptiles.

jhwegener
2006-Nov-18, 01:17 PM
there could have been more than one impact at about the same time (perhaps a pair of asteroids/comets or even more. Such pairs have been found and may be common). Perhaps scientists were "lucky" to find the crater at Yucatan. The other one(s), probably in deep ocean (covering about 3/4 of earths surface now. How much 65 million years ago?) and remains to be found. As long as the crater distribution is not "even" or random we can say it must be very incomplete.
About some groups of species "mysteriously" surviving (mammals, birds, crocodiles, snakes etcetera) while other did not (dinosaurs etcetera):
1: What conditions came in the period immediately after the impact(s)?
Some parts of the world probably much worse off than the rest(higher extinction rate). areas close to impact, and probably coastal lowlands (hit by tsunamis).
2: Immiediate drastic temperature change probably hit some animals and plants much worse. Perhaps warm blooded animals, protected by feathers/hairs had an advantage in this situation? If there in some areas were dark and about nothing to eat for a period, hibernation could be the only way to survive.
3: there may have been certain "protected places", perhaps caves and dungeons, narrow valleys(?), highlands, and some places under water (ocean/rivers lakes) were conditions changed little, and more species survived?
4: Even such details as the exact time of the year and day, the angle, velocity and composition may have meant the difference between extinction and survival for some species.
5:Perhaps very many of the surviving species almost become extinct in such a situation, so the difference between extinction or survival is often very marginal (depending on whether 99.99 or 100 % perish)

Delvo
2006-Nov-18, 04:50 PM
There were also differences between the different groups of animals themselves. Birds, for example, could fly, and the other small warm-blooded critters (mammals and small dinosaurs) could not. But mammals also had some differences from the small dinosaurs, despite similar size and warm-bloodedness: they're thought to have been nocturnal, and for the most part, they didn't lay eggs. The advantage of the former trait is obvious if the world goes dark for a while. The latter could have helped if temperatures dropped for a while because the young would have a better chance of survival inside a (relatively) big warm parent body than outside. And it could also have become a big advantage if food was scarce for a while, because as food sources became unavailable, eggs would remain available longer than most and animals that had run out of other things to eat wold be forced to eat whatever's left even if they wouldn't have eaten it before. (And mammals could very well have been better at finding and digesting eggs than other animals were anyway, because egg-eating is thought to have already been common among mammals all along anyway; before the comet impact idea came along, the most common belief was that they killed off the dinosaurs themselves just by getting too efficient at destroying the dinosaurs' eggs!)

John Mendenhall
2006-Nov-20, 10:46 PM
Thank you, Greenfeather, GBendt, et al. I will try to remember in the future that there can be page 2 and following in these threads. I was stuck on page 1 and wondering why it quit.

Re oxygen rich atmosphere: I have seen claims that green foliage will burn easily if the oxygen level is a few percent over today's level. Comments?

greenfeather
2006-Nov-21, 01:10 AM
Re oxygen rich atmosphere: I have seen claims that green foliage will burn easily if the oxygen level is few percent over today's level. Comments?

I have this DVD "Walking with Monsters", done by the folks who did "Walking with Dinosaurs". It has some great scenes in the Carboniferous era, and sure enough, it ends with a climactic forest fire started by lightning, mentioning how dangerous the fires were because the oxygen level was around 30 percent!

FutureQ
2007-Jun-28, 04:12 AM
I was amused to see mentioned here as parroted always that evidence for the extinction of the dinos is the KT event iridium layer. So here's an Occum's Razor for you.

If that layer is evidence for the dino demise then shouldn't it be closely associated? In fact should it not be directly associated as in touching some fossils? Nay not just touching but actually lying around such that by now it would appear as though underneath?

Mt. St. Helens is in my back yard. It is likely this fact that led my evolving considerations for the KT event theory. At first I loved it. I even speculated that the gulf area would be the impact area before that was discovered. It simply made sense for an amateur's hunch owing to its shape.

But something started nagging at me. I witnessed quite up close and personal like fallout of a largish scale with Helen's 1980 dustup. I witnessed the action of weather on this fallout. Imagine that a junkyard full of autos represent for a thought experiment thousands of dino's carcasses lying about killed nearly instantly for some and within weeks for others based on the theories so far pushed. So where today in Eastern Washington junkyards, do you suppose you'd find the ash fallout from the 1980 eruption and even just a couple years after?

That's right, underneath! Indeed if a nuke winter happened as proposed then since the small fury alleged inheritors of Earth could not dis articulate large masses of frozen bodies you'd expect to find a great number of nicely articulated fossils still to this day and the iridium layer WOULD NOT BE FOUND AS MUCH AS 12 FEET ABOVE!! That people don't find the distances reported between last dino and the KT layer problematic is just amazing to me. How much sediment can accumulate, on average worldwide, in a couple years, 12-14 feet worth?! I seriously doubt it!

Do any of you have the ability to make movies of the mind? I can and when I plug in the proposed sequences of proposed events I find a serious conundrum every time.

The only thing that fits is that the dinos were already gone well before the event and oh yes it did slam the Earth but sorry the dinos were already goners.

This below, in greater detail, is my attempt to share this with a believer [aka scientist unchangingly set in his ilk's pet theory]

I appologize for some repetition.


Dear Dr. F,

I just watched you on a program about comets and asteroids make the argument that, "If you have evidence of an impact and almost all life disappears thereafter then it's not hard to make the assumption these are cause and effect related...[sic]". Sorry my recollection of your exact words is vague but the thought is there.

The problem is that this is wrong. It is too simple an answer arrived at too quickly and possibly even contaminated by a perceived need to push a certain political view, that we need more watchers watching for inbound objects that might threaten our existence. While I support the real need to alleviate the real threat of enormous damage and even possible extinctions that may occur with an impact event, I cannot condone pushing a flawed theory as fact everywhere I turn in order to do so.

Here is an even simpler alternate view.

If the KT boundary were evidence of extinction, shouldn't it be intimately intertwined in the REAL evidence of mass death, the remains of all the last dinosaurs?

I'm a 3D thinker. I can make really good visual representations in my mind of almost anything. I've done so with the alleged impact event and here is what I see entailed in a letter I was once going to send to a science magazine. I never did thinking they wouldn't listen to an amateur anyway. Maybe you will.

[begin quoted material] Note to reader:

[The following below is a draft of a letter I meant to send to Frontier magazine after they yet again parroted this lame excuse for a theory. First for greater clarification I will make a comparison to a hypothetical event. Suppose we wiped ourselves out with a global nuclear exchange. For sake of argument let's say everyone dies, human that is. The proverbial nuclear winter resides for a season or two or more maybe. How long doesn't matter much because we are talking about only a blip of time compared to geologic time. In other words not many floods and volcanoes will be burying our remains and refuse and evidence for existence in the comparatively short span of a nuclear winter. Besides many processes would be slowed by so much ice... no? So imagine when someone digs us up one day and let's say that the nuclear winter lasted as much as 100 years.

Where would you expect to find the radioactive layer in relation to our bones and our hulking cars and houses and buildings? Would you expect 12 to 14 feet of sediment to separate us from that radioactive dust layer? Well if we were dinosaurs and the great Alvarez's had passed judgment on our passing you would, but does that mean it's right? I am plagued with a logical to a fault and staunchly common sensible mind. I can't help seeing the dust find it's way below, beside and directly on top of our remains. Read my little thought experiment and see if you agree.]

<snip>

Asteroids and Comets Falsely Accused Enough is enough!

Everywhere I turn someone quotes this lame theory that the 65M KT-boundary layer impact event caused the Dinosaurs demise (Oct '98' FF, Retrofire letter, Article "Destination Asteroid". It is nonsense and bad science with little common sense applied at all. I cannot believe so many so called, "great minds" have bought this pig without so much as a poke! The flimsy evidence would not stand up in a court of law even if asteroids and comets were on trial for Dino murder! Perhaps it has prevailed because the pushers of asteroid or comet impact paranoia need for there to be a scary mass extinction to convince us the need to watch the skies more closely. Well it is sexy, but it just is not the truth, at least not proved absolutely as so, yet.

I have no problem with the fact that a comet or asteroid did impact 65 millions years ago and that the iridium laden clay is the evidence of it among other things. It, to me, is a fact -- the impact occurred, but the dinosaurs were long dead before that.

The simplest way to describe my theory is to condense it to one statement. "If the boundary layer is indeed the evidence of a dinosaur extinction causing impact, then it should be really easy to find an overwhelming number of fully articulated and complete dinosaur skeletons... just look for them where the boundary layer is found" If we do a simple thought experiment I believe we can expunge the KT boundary issue as the cause of the mass extinction once and for all. Those readers that are capable of mental spatial visualization start by gathering some information about the subject that is diverse and then assemble a possible scenario. Apply logic to each event sequence of the popular theory and the obvious becomes clear.

Here, very much condensed, is how I did my thought experiment, Scientists please let it be your guide.

Going on the assumption that the Alvarez's theory is correct I imagine that I am watching as it allegedly happened. I see the comet hit and the ejecta being thrown up and out, then the dust rising up and blocking the sun. Then I watch as over several days or weeks things get really cold (according to the latest update of the popular theory) and animals that survived the initial fires close to the impact area begin to die. First the herbivores then the carnivores, cold is no respecter of diet so the carnivores don't outlast the herbivores by much. This is important because as the large carnivores and scavengers die off, too soon to do much damage to the overwhelming abundance of food carcasses, only the very small cold resistant animals are left to eat the carcasses and scatter bones, those small fury mammals that lead to us eventually.

These are too small to scatter large bones and rapidly the huge amount of dead flesh around is getting too solid from the cold to even be accessible except for perhaps by underside tunnels made by the small animals to exploit for awhile longer this abundant larder.

The next main event is the fallout of the dust that has been blocking the sun. The latest report is that the 1/2 inch layer may have precipitated in a single year. I watch as it begins to blanket the Earth and of course the many frozen bodies. Simultaneously as there becomes less to block the Sun there becomes more to cover and help warm everything that is frozen. The dust is darker than snow and ice and so absorbs the ever brightening Sun's rays and begins to rapidly thaw all the dead bodies. As the ice melts water begins to flow and run off carrying the dust with it from off the tops of the bodies.

Another thing happening is the simultaneous sublimation of the huge amounts of ice to water vapor which clings to the remaining airborne dust particles causing a lot of rain. More and more dust is being washed off the TOPS of the bodies and into LOWER level depressions around and UNDERNEATH the bodies and in general just flowing into lower elevations. Interestingly this means that the still largely whole thawing bodies would be to a large degree actually above the KT boundary!

Soon mostly everything is thawed out and being eaten as fast as possible by the lucky inheritors of the dinosaur's world. However, they are for now few in number and still too small to drag the excessively huge number of large dino bones around. Consequently, for a long time very complete articulated skeletons and some flesh remains would linger as the slow process of decay and fossilization take their inexorable courses.

Conclusion: If the KT boundary IS INDEED the "smoking gun" of dinosaur demise we should be able to look no further than AT OR JUST ABOVE the KT (Cretaceaus/Tertiary) boundary to find huge numbers of fully articulated and complete dinosaur fossils that were allegedly the victims of the impact. As far as I know every piece of evidence so far shouts "no dinos found in the tertiary period". Furthermore I have never seen evidence or claims of any dino fossils being found any less than several feet BELOW the KT boundary.
Wouldn't this fact be obvious to the scientists purporting this theory? If an event is a cause, shouldn't evidence of said event be CLOSELY related to all evidence of effect? The dinosaurs had to already have been extinct as their bones were already buried well below the surface when the impact occurred. This would hold true even when allowing statistically for common "dirt disturbing" geological processes, such as localized floods, earthquakes, slides, volcano eruptions, etc. If the KT event theory were true there should be many heaps upon heaps of complete and well articulated skeletal fossils closely associated with the KT boundary layer. The iridium laden layer should be below, beside, entwined within and only rarely immediately above due to the chaotic forces involved in the precipitation of it from the atmosphere.

FutureQ

P.S. I heard that Phil's new book may cover this event. I hope he sees what I have speculated here.

Ronald Brak
2007-Jun-28, 04:52 AM
If the average life span of a dinosaur was 10 years then even if all almost all dinosaurs were killed by the KT impact it would only result in as many dinosaur remains as were produced every 10 years. But despite a generation's worth of dinosaur remains being produced every 10 years we don't have a continuous record of fossils. There are very large gaps of time between the estimated age of most dinosaur finds. Often hundreds of thousands of years. We might only have about one find for every 10,000 generations worth of dinosaur remains. This suggests that the odds of discovering even one find that was a direct result of the KT impact is quite low.

hhEb09'1
2007-Jun-28, 04:57 PM
It is too simple an answer arrived at too quickly and possibly even contaminated by a perceived need to push a certain political viewThe Alvarezs had no such agenda. Apparently, you do, or why would you bring it up?


Soon mostly everything is thawed out and being eaten as fast as possible by the lucky inheritors of the dinosaur's world. However, they are for now few in number and still too small to drag the excessively huge number of large dino bones around. Consequently, for a long time very complete articulated skeletons and some flesh remains would linger as the slow process of decay and fossilization take their inexorable courses.Fossilization does not take place above ground. If the carcasses remain above ground, they will disappear.

Tucson_Tim
2007-Jun-28, 06:56 PM
I even speculated that the gulf area would be the impact area before that was discovered. It simply made sense for an amateur's hunch owing to its shape.

I don't believe the Gulf's shape has anything to do with the crater at the tip of the Yucatan Penninsula.

Also, here is a quote from wikipedia:



Evidence pointed to possible crater sites off the north coast of Colombia or near the western tip of Cuba. Then Carlos Byars, a reporter for the Houston Chronicle, contacted Hildebrand and told him that a geophysicist named Glen Penfield had discovered what might be the impact crater in 1978, buried under the northern Yucatán Peninsula.


It wasn't verified till the early 1990s though. So, you knew before then?

John Mendenhall
2007-Jun-28, 07:17 PM
I was amused to see mentioned here as parroted always that evidence for the extinction of the dinos is the KT event iridium layer. So here's an Occum's Razor for you.

If that layer is evidence for the dino demise then shouldn't it be closely associated? In fact should it not be directly associated as in touching some fossils? Nay not just touching but actually lying around such that by now it would appear as though underneath?

We know that:
1. There was at least one impact.
2. The dinosaurs disappeared.

This is known. No speculation. No guessing about fossils, or what survived, or anything else.

Think about Showmaker-Levy at Jupiter. A series of 25 million megaton explosions. We're lucky our mammalian ancestors survived.

It's neat, it's clean, and it irritates old school paleontologists to no end. Take claims that the dinosaurs were extinct way prior to the K-T with a grain of salt; these guys do have a political agenda. If you'd like a parallel situation, lots of astronomers were very unhappy to hear that 'spiral nebulae' were actually external galaxies, with resolvable stars. Some refused to accept the evidence.

hhEb09'1
2007-Jun-29, 03:55 AM
It's neat, it's clean, If it were neat and clean, there'd be no argument. It's pretty fuzzy actually.

Ronald Brak
2007-Jun-29, 05:10 AM
Just reading about how a dinosaur find may have been dated as being after the KT boundry. If correct it indicates some non avian dinosaurs survived the KT impact and re-established themselves before later following the route of most species and becoming extinct.

FutureQ
2007-Jul-03, 04:12 AM
If the average life span of a dinosaur was 10 years then even if all almost all dinosaurs were killed by the KT impact it would only result in as many dinosaur remains as were produced every 10 years. But despite a generation's worth of dinosaur remains being produced every 10 years we don't have a continuous record of fossils. There are very large gaps of time between the estimated age of most dinosaur finds. Often hundreds of thousands of years. We might only have about one find for every 10,000 generations worth of dinosaur remains. This suggests that the odds of discovering even one find that was a direct result of the KT impact is quite low.


I strongly disagree and I am stunned that you and others here don't see why. Sure, it is absolutely true that any or all fossilization is rare, umm, under so called usual circumstances. The KT event if it happened as discribed would have been ANYHING BUT biz as usual. Yes, it's one thing to get the admitted highly improbable confluence of events just right for fossilization when you have a single death here, the another there, and everywhere all over this hit and miss haphazard circmstance spread over vast amounts of time where in all likelihood the ingredients needed for fossilization would hardly be the same or even near it for each separate death event. Something that should advise here is that we usually find fossils where mass deaths have occured like floods and slumps and volcanic flows, etc. The key point here is having many deaths all at once under more similar situations. Now take that around the globe and figure on billions of animals and certainly you can see the incidence of fossilization should have been greatly increased. Even if it were only 1%-3% that would mean thousands of fossils directly related to the KT event. This should be simply obvious. The stark absence of them speaks volumes.

Uh, regarding fossils not forming above grund. Well of course not. I didn't think that here I would need to fill n the details how the subsequnt fossilization would have ccured. The point was to show that long before ANY fossilization dould have occured the iridiu layer would have been washed of the tops of still remaining carcasses. I didn't think this was so dificult to visualize. The random fossilization of all those carcasess, those lucky enough, would have gone on as expected. Geological and weather processes would eventually continue as usual and so slumps and etc., would have covered over some of those nicely already dead fresh frozen larder. In fact I would expect the fallout to in some cases aid the procress by encasing bodies like a concrete shell, again from my volcanic ash experience. Water plus dust plus ash equals hard shell cum fossil.

FutureQ

FutureQ
2007-Jul-03, 04:25 AM
Just reading about how a dinosaur find may have been dated as being after the KT boundry. If correct it indicates some non avian dinosaurs survived the KT impact and re-established themselves before later following the route of most species and becoming extinct.

Is this not problematic for the so often pushed hypothesis of re impacting ejecta heating up from friction in the atmosphere then itself adding to the heat of the atmosphere to upwards of 600 degrees? I just watched the latest Science Channel appologist sci-tainment documentary cum movie pushing that very thing. I don't necessarily buy that thinking because I think too much life survived for condiitions to have gotten THAT bad.

I wish those investigating these theories would break it down into finer time decrements and then follow logic when deciding if a proposal actually would lead to some of the expected consequences.

I just hate that some say, the dinos were there, then the dirt cloud fell then the dinos aren't and think it rests with that. That is a logical fallacy known as ad hoc ergo propter hoc. The determination of the truth is in the finer detasils and I just don't believe they have yet been teased out enough. [Oops I think i meant "post hoc" abone, sorry all.]

FutureQ

Ronald Brak
2007-Jul-03, 04:34 AM
A large impact could certainly result in events that increase the likelyhood of some remains being fossilized. But it could also result in events that would decrease the likelyhood of fossil remains being left. Just which effect would dominate I can not begin to speculate on. We do know that despite continuous volcanic activity throughout the age of dinosaurs the fossil record still has very large gaps which suggests that ash on remains doesn't leave many fossils that we can find today. Thus I still think that finding fossils that are a direct result of the KT impact will be very difficult.

Ronald Brak
2007-Jul-03, 04:37 AM
Is this not problematic for the so often pushed hypothesis of re impacting ejecta heating up from friction in the atmosphere then itself adding to the heat of the atmosphere to upwards of 600 degrees? I just watched the latest Science Channel appologist sci-tainment documentary cum movie pushing that very thing. I don't necessarily buy that thinking because I think too much life survived for condiitions to have gotten THAT bad.

The earth's atmosphere as a whole reached 600 degrees? I've never heard of this. But then I don't watch TV.

FutureQ
2007-Jul-03, 04:39 AM
The Alvarezs had no such agenda. Apparently, you do, or why would you bring it up?Fossilization does not take place above ground. If the carcasses remain above ground, they will disappear.

Huh? Look, before you get you back up for no reason and cast blind aspersions you might like to know that I live on a little over $6000 a year social security disability so I am hardly affiliated with anyone pushing ANY political agenda. All I want is the truth and I don't think we're yet there. It's not the Alvarez's I was referring to.

Furthermore, I fully support the political effort to get more eyes on extinction causing dirt clouds from space! For folks sake! I want to live as much as, actually a lot more than, the next guy.

I'm just not willing to allow bad science to be pushed as truth, because it meets and end more epediently, simply because it has a sexy even 'Hollywood' celebrity of its own. It's a sexy scary horror filled thing to consider and I agree it can happen again and it certainly killed plenty of critters the several times it has happened in the past.

But alas most of the dinos were long gone when the KT event occured.

C'mon people how many years does it take to cause 12-14 feet of sedimentary rock layering buildup? Would you expect the last dinos to be THAT FAR DOWN below the supposed smoking gun's smoke?

FutureQ

FutureQ
2007-Jul-03, 04:53 AM
We know that:
1. There was at least one impact.
2. The dinosaurs disappeared.

This is known. No speculation. No guessing about fossils, or what survived, or anything else.

Yes, indeed, it is known as post hoc ergo propter hoc. I believe I said in another post 'ad hoc ergo...' I made a brain fart, correcting it here. This now you see it now you don't thinking is what I referred to as TOO SIMPLE.

One hears a shot then footsteps leading away or were they coming toward, in the excitment it's so hard to tell. We look in the room and a man holds a gun leaning over a dead body. He must be the guilty party right? Wrong, we missed the finer details of the real perp running away as this Samaritan ran toward to help and stupidy thoughtlessly picked up the real perps gun. But post hoc ergo propter hoc is so neat and clean is it not?




Think about Showmaker-Levy at Jupiter. A series of 25 million megaton explosions. We're lucky our mammalian ancestors survived.

It's neat, it's clean, and it irritates old school paleontologists to no end. Take claims that the dinosaurs were extinct way prior to the K-T with a grain of salt; these guys do have a political agenda. If you'd like a parallel situation, lots of astronomers were very unhappy to hear that 'spiral nebulae' were actually external galaxies, with resolvable stars. Some refused to accept the evidence.

I think if you really try to see the events in smaller time segments as they logically would have if (that's the only IF really) unfold you may come to a less neat realization.

FutureQ

hhEb09'1
2007-Jul-03, 05:01 AM
In fact I would expect the fallout to in some cases aid the procress by encasing bodies like a concrete shell, again from my volcanic ash experience. Water plus dust plus ash equals hard shell cum fossil.If they're encased in it, then they're under it, right? You can't have it both ways. You can't have the layer protect them so that they can be fossilized, and be washed off too.

If it's washed off, and there is no slumping or volcanic ash or flash flood sediment covering them, the chances of fossilization are almost zero.
Huh? Look, before you get you back up for no reason and cast blind aspersions you might like to know that I live on a little over $6000 a year social security disability so I am hardly affiliated with anyone pushing ANY political agenda. All I want is the truth and I don't think we're yet there. It's not the Alvarez's I was referring to.It's the Alvarezs who advocated the theory. I was not casting blind aspersions--I was only responding to your aspersions. But I'm willing to forget about the accusations of political agendas, if you will

FutureQ
2007-Jul-03, 05:07 AM
The earth's atmosphere as a whole reached 600 degrees? I've never heard of this. But then I don't watch TV.

I feel ya! But alas I have too much time on my hands so forgive me if do watch a lot of TV. Although in my defense it is usually only science and tech in nature. I also have my pc right in front of me google ready at hand as I sit here in bed basically 24/7. Maybe this expains how I have so much time to just sit and concentrate on this particular burr in my saddle. ;)

Nice to meet everyone, thanks for joining the convo.

FutureQ

P.S. I am curious what scenarios you hypothesize could disrupt fossilization owing only to the factor of there being a vast excess of remains available. Keep in mind we would also have a situation of scale where there couldn't have been much scavenging damage since the only supposed critters left were for the main shrew sized.

Ronald Brak
2007-Jul-03, 05:24 AM
P.S. I am curious what scenarios you hypothesize could disrupt fossilization owing only to the factor of there being a vast excess of remains available. Keep in mind we would also have a situation of scale where there couldn't have been much scavenging damage since the only supposed critters left were for the main shrew sized.

Well, just off the top of my head, I would say that things that deposit material such as landslides and falling ash could increase the chances of fossilization, but things that erode material such as tsunamis, torrential rains, and dust storms would reduce chances. Then there are the effects of fires either sparked by the impact or occurring later due to dead dried vegetation. I can also imagine surviving carnivours and carrion eaters desperately searching for the sent of buried carcasses and digging them up. It probably took time for the larger animals to die off and we don't know much extinction was due to the initial effects of the impact and how much was due to the climatic/ecological changes it sparked. (But I think the initial effects were probably quite severe.)

hhEb09'1
2007-Jul-03, 05:28 AM
P.S. I am curious what scenarios you hypothesize could disrupt fossilization owing only to the factor of there being a vast excess of remains available. Keep in mind we would also have a situation of scale where there couldn't have been much scavenging damage since the only supposed critters left were for the main shrew sized.That's just the way fossilization works--it mostly doesn't. Look at an animal that died on the prairie--hardly recognizable after just a few years. And it's the small (and very small) animals that are doing the scavenging. And there's weathering. Even when an animal is buried in tar or ice (ok not technically fossilization) or river sand or volcanic ash flow, it takes a long time to produce a fossil--and all sorts of things can interfere and prevent it from happening.

FutureQ
2007-Jul-03, 05:29 AM
If they're encased in it, then they're under it, right? You can't have it both ways. You can't have the layer protect them so that they can be fossilized, and be washed off too.

If it's washed off, and there is no slumping or volcanic ash or flash flood sediment covering them, the chances of fossilization are almost zero.It's the Alvarezs who advocated the theory. I was not casting blind aspersions--I was only responding to your aspersions. But I'm willing to forget about the accusations of political agendas, if you will

Forgive me for not painting in more of the details. I speak very succintly sometimes not expecting to have to elucidate every finer point for the so called choir but here I did say, "some". I did not flip flop, one can have some encased and some not. We are after all talklking about perhaps billions of dead critters all over the entire surface of the Earth. Encasement or not would depend on humidity levels and wind levels and absence or not of precipitation. This ain't rocket science. I can too have it both ways because if you would please read again my small paper that I wrote I said one would expect to find the iridium layer above, through and below.... but the key is close to. I assumed science minded people would fill in some details on their own to get at exactly how but I did describe this to some extent.

And again the real point is not so much our not finding a great number of fossils as I describe they should be if the events happened as the theories describe. That is the high bar, that is the perfect outcome. The low bar, the kicker, the deal killer, is you would not expect several hundred thousands to even millions of years of sediment to build up above the very last found dinos and at the top of that find the so called evidence of their demise. If it is indeed evidence of their demise THEN wherever you find fossils even if only miniscule amounts the iridium layer should be close, very close, by. This is the point!

I invite everyone to try doing this thought experiment in your own mind. See what results you get.

FutureQ

P.S. Polical agendas gladly buried. ;)

FutureQ
2007-Jul-03, 05:43 AM
Well, just off the top of my head, I would say that things that deposit material such as landslides and falling ash could increase the chances of fossilization, but things that erode material such as tsunamis, torrential rains, and dust storms would reduce chances. Then there are the effects of fires either sparked by the impact or occurring later due to dead dried vegetation. I can also imagine surviving carnivours and carrion eaters desperately searching for the sent of buried carcasses and digging them up. It probably took time for the larger animals to die off and we don't know much extinction was due to the initial effects of the impact and how much was due to the climatic/ecological changes it sparked. (But I think the initial effects were probably quite severe.)

Well you've discovered something that bears telling. As I have watched this theory or cluster of theories evolve the immediate effects have grown ever increasingly violent. It is to the point where the severity itself demeans the theory. One guy the other day had the atmosphere igniting, becoming unbreathable, every living thing extinguished enmasse immediately. This clearly begs the question then why is anything alive today that decended from anything alive before the event?

It used to be that the nuke winter was the big killer and it started off slowly but within mere weeks, long before THAT MUCH dead carrion could be disposed of, set in quickly enough to be killing all but the fur covered... the very tiny fur covered.

They keep revising but it still doesn't change the fact that the iridium and soot/clay fallout layer should be closer to the last alive dinos than 12-14 feet above them with many many sediment layers in between.

I just want someone to explain how that happens.

FutureQ

P.S. With that I bid all a good night for now.