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Re: extinction



> Dear List Members!
> Hear is a translation of my 3 years old article pair. Let us discuss that!

:-)

Well then.

> What is the most fashionable theory for what happened about 65 million
> years ago when "the late Cretaceous extinctions not only caused the demise
> of the dinosaurs but also accounted for the huge losses of the
> Foraminifers, the unicellular animals that serve as the basis of the sea
> food chain",

Not only those! Few groups of living things were not affected. Spend a few
hours in the archives of this list http://www.cmnh.org/dinoarch, and you'll
find some more victims.

> That theory is, "the extinctions at the end of the Cretaceous period were
> triggered by a giant meteorite that had collided with the Earth. The
> supposed chain of events leading to mass extinction is as follows: A cloud
> of dust formed after the impact covering the whole Earth and causing
> darkness for months or even for years, the collapse of photosynthesis,
> drastic climatic change, and the breakdown of food chains."

This is only a small part of the scenario. The darkening and cooling would
have resulted not so much from dust (newer simulations have shown that there
wouldn't be very much dust), but from nitrogen dioxide and from soot, which
resulted from more or less global wildfires (the NO2 also from the impact
itself), as well as from sulfuric acid aerosols which resulted from the SO2
which in turn resulted from the impact in anhydrite = almost waterless
gypsum = calcium sulfate. In addition to the darkness and the fires, lots of
incredibly acidic rain are supposed to have fallen (because of the NO2, SO2
and CO2), evidence for ludicrously big tsunami has been found (as you'll
find in the archives; tsunami are already preassumed in
http://www.dinosauria.com/jdp/impact/wham.htm); local extra effects such as
http://www.dinosauria.com/jdp/impact/impact.htm have been hypothesized; and
last but not least the impact itself, equivalent to an earthquake of
magnitude 10 to 13 on the Richter scale, must have killed lots of big
terrestrial animals (keep in mind that the Richter scale is logarithmic,
which means that 10 is 10 times as strong as 9, and that real earthquakes
probably cannot surpass magnitude 10). Before I forget, the CO2, and the
methane that must have flushed up from the trembling continental slopes in
huge quantities, produced a strong greenhouse effect after the darkness &
cold was over. It lasted for a few 100 or 1000 years and is seen in marine
sediments with very high resolution.

> INTRODUCTION
>
> There is a well known story:
>
> The scientist takes a flea. He puts it on the table and says, "Jump, you
> flea!", and the flea jumps. He grabs it again and tears out its jumping
> legs and orders it to jump again. The flea does not jump this time.
> Therefore the scientist states that fleas hear with their jumping legs.

If he does that, he isn't a scientist. :-)

> WHY IMPACT THEORY IS NOT AN ADEQUATE EXPLANATION?
>
> Certainly there are other facts that we could bring up against this
> hypothesis but it is unnecessary to introduce all of them for the
> confutation.

On this list, however, just as in a scientific paper, it _is_ necessary to
bring up _all_ of them.

> 1. On page 132 of the above mentioned book we find "according to the
> estimates, 200 gigatons (billion tons) of vapor and the same amount of
> sulfur dioxide penetrated into the atmosphere." And all this happened
> suddenly, resembling an explosion due to the impact.

"Resembling"? It _is_ an explosion. The kinetic energy (1/2 x mass x
velocity²) of a body 12 km across, moving at several thousands to tens of
thousands of km/h, is beyond good and evil. There is no doubt that, apart
from a few splinters, the asteroid was immediately vaporized in the impact,
along with tens of km³ of target rock.

> Sulfur dioxide kills virtually all living creatures. Therefore:

Wait, wait! You assume that the SO2 stays at the ground! But why should it?
The impact blasts it above the stratosphere, and while it sinks down into
the upper troposphere again, it gradually oxidizes to SO3 and finally
combines with water to H2SO4 -- sulfuric acid.

> Then where is this huge amount of fossils?

Here. http://www.dinosauria.com/jdp/fossil/bonez.htm

In addition, keep in mind that most of the living beings that died in the
impact and its aftermath would have died anyway within 100 years or so. When
it's 65 _million_ years ago, we can't tell 1 year apart from 100, and only
in very few sediments can tell 1 year apart from 1000. In other words, we
would _not_ expect to find a bone spike in the first place!

> (With seas the situation is different since here solution and dispersion
> take place much slower than in the atmosphere and binding processes may
> also reduce the sulfur dioxide concentration.

Yeah. Those binding processes make sulfuric acid of it. Which fits the
theory as well as the data; the latter point to a "Strangelove ocean" -- the
upper layers of the oceans were practically sterilized, as e. g. briefly
mentioned here http://www.dinosauria.com/jdp/impact/wham.htm.

> 2. The hypothetical location is the Mexican Gulf. The tsunami had not got
> beyond the gulf according to the referred book. Opposed to this, the
> Krakatau-explosion at the end of the 19th century - fortunately - causing
> only a fragment of such a large-scale disaster, caused a tsunami on the
> whole earth.

Now come on. The tsunami produced by Krakatau was a few _millimeters_ high
when it reached Europe! Such phenomena don't fossilize.

> A powerful tsunami would have devastated the eggs in the
> seashore sand, the living creatures and ovules on the coast and in the
> shallow water, etc.
>
> Where are the huge amount of fossil records of such drifted and buried
> living things?

See above.
Tsunami deposits, e. g. with tree trunks, have been found.

> 3.   As a result of the heat effect, all the living creatures nearby
> disappeared (not only died but evaporated), further away, all living
> creatures died but remained in destroyed forms and partly charred, further
> still the devastation is selective. All this happened over such a vast
> area that (along with the effect of the sulfur dioxide) it should have
> produced fossils in large quantities.
> Where are all these likewise particular fossils?

Same.
And don't forget the few surviving scavengers! :-)

> 6. Iridium anomalies have been found all over the world but:
> -  Iridium has such a high melting and boiling points that as a result of
> the impact it could only partly become vapor.

Wrong -- because it is contained even in meteorites in incredibly small
quantities! We're talking about ppb, parts per billion, here. 1 ppb Ir means
that of 1,000,000,000 atoms 1 is an iridium atom. There is no metallic
iridium in meteorites.

> -  Due to its heavy weight it would have settled back very quickly onto
> the surface of the earth.

Single atoms don't have such heavy weight... and in any case, it certainly
did settle back quite quickly. There's nothing in the boundary layer that
would suggest it didn't.

> So as the distance from the impact increases the iridium concentration
> quickly decreases. (This is only true above a minimal distance since the
> mechanical effect of the impact blows the pieces away.)

Also wrong -- because of the sheer size of the explosion. Lots of material
were blown into an orbit, and therefore came down in an even distribution
all over the world.

> Do the iridium concentration values found show any corresponding
> dispersion?

No. There is not less iridium in the boundary layer of New Zealand than in
that of Montana.

> (The value in Gubbio, Italy showed a value ninety times higher
> than the average, while in Stevns Klint, Denmark, it was one hundred and
> sixty times higher.

We have another effect here... these values are measured per volume. I bet
that sedimentation in Gubbio was faster than in Stevns Klint, therefore the
Ir was deposited as part of a thicker layer, while in Stevns Klint all the
Ir is crowded into less space.

> They also had determined the direction of the impact and according to
> their estimates the strongest effect should have been northwestwards.
> Do the concentration values found correspond to this?

No -- and they shouldn't, see above.

> 7. There are some facts that are contradictory to the worldwide biological
> extinctions. For example, although in North-America a change had taken
> place in the flora, it has not occurred either in the Antarctica or in
> New-Zealand.

I don't know about Antarctica, but it did take place in New Zealand, which
probably burnt down. Temporarily _all_ angiosperms disappeared from there,
it seems.

Vivi Vajda, J. Ian Raine, Christopher J. Hollis: Indication of Global
Deforestation at the Cretaceous-Tertiary Boundary by New Zealand Fern Spike,
Science 294, 1700 -- 1702

Scroll down to about the middle of
http://www.cmnh.org/dinoarch/2002Nov/msg00327.html to read some excerpts
from that paper and more comments by me.

> 8. If the explanation proposed to account for this theory was adequate in
> the case of the survival of crocodiles, distant relatives of dinosaurs
> (i.e. they are fresh-water animals),

Some rather marine crocs (Dyrosauridae) survived, too.

> then why did birds (as opposed to all
> the flying reptiles) survive the catastrophe, among of which there were
> plenty of marine ones and ones dwelling far off the waters at these times?

Most birds didn't survive. The entire diversity of Enantiornithes, for
example, as well as all close relatives of *Ichthyornis* (one such bird has
been found in the Maastricht Formation -- close to the boundary) and
*Hesperornis*.
        There seem to have been rather few "modern" birds (Neornithes, the
group to which all Cenozoic birds belong) in the Cretaceous. Perhaps you
have read older literature which reports owls, woodpeckers and whatnot in
Late Cretaceous layers -- almost all of these fragments have been
reinterpreted.

> Or turtles (while the ancient marine reptiles all disappeared)?

Turtles did get through with rather few casualties. Well, they don't need
much food... and it's enough if a few buried eggs survive somewhere in some
alkaline soil to let the species survive.

> And why did arthropods survive once sulfur dioxide,
> being much heavier than the air, may have even
> been enriched nearby the surface of the earth?

It certainly wasn't, see above. However, herbivorous insects did become very
rare, judging from comparisons of latest Cretaceous to earliest Paleocene
leaf fossils.

> And what about the mammals living on the
> surface and in pits? Where were these intact or
> slightly damaged groups of animals during the huge fires and smoke?

Perhaps in burrows... and then we can't assume that the _entire_ land
surface was burning... and many mammals did die out. North America had a
rich fauna of marsupial relatives in the Maastrichtian but not in the
Paleocene (or later).

> 9. The "evidence" proposed to account for the theory's adequacy (just as I
> have already proven it above in certain cases) is only useful to confirm
> the fact of an impact and to demonstrate the location of it. But they do
> not sate whether the impact indeed was as powerful as previously assumed?
> Was it large enough to trigger such an effect?

The crater is quite large. It isn't certain just how big it was, but a few
other craters elsewhere (such as the Silverpit crater in the North Sea) may
come to the rescue. The (total) size of the impactor(s) was first calculated
from the estimated amount of iridium in the global boundary layer 10 years
before the Chicxulub crater was found; the result was an asteroid of 6 to 12
km in diameter. Imagine Mount Everest, once or twice, falling from the sky
at a speed many times that of, say, a gun bullet. This _is_ enough.

> II. A BETTER EXPLANATION FOR THE LATE CRETACEOUS EVENTS
>
> It is not yet known how long it took for the dinosaurs, ammonites, etc. to
> die out, for we still have no means or method for determining so.

Incorrect. The method is not terribly precise, but quite simple -- we just
have to find out how common their fossils are in which layers, and to do
lots of statistics to correct for the vagaries of preservation. The longer
people keep looking, the more dinosaur and ammonite fossils they find below
but not above the boundary, and the more sudden does the extinction look.
        The youngest known ammonite was found 10 cm below the boundary
layer. :-) The youngest known non-avian dinosaur tracks are 37 cm below the
layer.

> Under normal circumstances surface waters are more rich in the C13 isotope
> than water in layers below. Therefore, lime skeletons of creatures living
> on the earth's surface contain more of this isotope than those living
> lower, but as the Cretaceous period ended, so did this significant
> difference. Not until much later did this phenomenon reappear. Scientists
> can determine only that this difference was formed within a 10,000 year
> time period.

There is not much in geology which can be dated with more precision. But
deep-sea sediments sometimes allow twice as good resolution, as e. g.
mentioned in http://www.dinosauria.com/jdp/impact/wham.htm. The main trick
is cyclostratigraphy -- the art of finding Milankovic cycles in sediments.

> Iridium anomalies also fail to give a more precise figure.

:-) How could they?

> It is possible, that as a result of a cosmic effect around this time
> iridium levels may have fallen suddenly and drastically.

Fallen???

> This could be a result of the earth having traversed
> one or more clouds of dust or meteoric material.

Ludicrously thick clouds... which wouldn't have left the crater that cannot
be ignored.

>  Iridium falling off, possibly other materials accompanying it,
> radiation, or a change in other environmental factors gradually
> accumulating may have caused the extinction.

Radiation? And how should Ir have contributed to the extinction?

> (Such death caused by accumulation was triggered, for example, by rising
> DDT-levels in the case of carnivorous bird eggs. There was a possibly
> similar case, namely the frequent occurrence of the egg in the egg
> phenomenon at one of the French dinosaur provenances in the Late
> Cretaceous. The small animals could not break through the shells of the
> eggs laid with double walls and therefore died.)

3 problems:
- Those eggs come from sauropods -- herbivores, not 1st or 2nd or 3rd order
carnivores like birds of prey.
- The phenomenon is not statistically significant.
- The phenomenon is not global.

> Accumulation may also have had a selective effect. (In the DDT example,
> the DDT did not destroy insectivorous birds or ticks.)

This is by no means selective. The probability of death depends on the
amount of ingested DDT per body mass or some such resistance parameter.
        DDT can be ingested but not excreted. When DDT is sprayed over a
landscape, it gets into the plants first. Then herbivores eat the plants,
accumulating the DDT in their bodies about 10fold. The same happens to the
1st order carnivores, which, after eating a certain mass of herbivores,
contain as much DDT as if they had eaten 10 times that mass of plants. And
so on. This is why DDT did not destroy insectivorous birds -- largely 1st
order carnivores -- but birds of prey -- for the most part 2nd order
carnivores.

> This process, having lasted for a long period of time, may have enabled
> certain species to become resistant.

Against what?

> This theory is not 'disturbed' by the fact that there may also have been a
> (possibly giant) meteor impact around this time,

At least one such impact did happen. This is beyond reasonable doubt.

> This theory explains why iridium anomaly has been found all over,

As does the impact hypothesis.

> since due
> to iridium's very low reactivity and its high melting and boiling point
> even the tiny iridium particles could penetrate through the atmosphere.

There are no iridium particles, because iridium is so damn rare. (Except
under strange circumstances, like in some places in the Ural where nuggets
of an alloy of osmium, iridium and similar inert metals are lying around.)

> (Even pure oxygen does not react to iridium when the latter is either
> heated while dropping quickly or cooler when falling slowly. Iridium does
> not react to nitrogen either under similar circumstances.)

This is part of the reason why it isn't poisonous. :-)

> How large might have been the amount of the additional material reaching
> the earth?
>
> According to page 132 of the book that I referred to in the previous
> material the celestial body colliding with the Earth had a diameter of 10
> km. The book also stated that its maximum speed reached 5km/s. Therefore
> it penetrated the atmosphere in about 10 seconds. If this amount of
material
> only had been arriving for one year out of 10,000 years,

The boundary layer was certainly deposited in considerably less than 10,000
years -- the fossil-poor layers above it are much thicker.
        I also can't imagine an Ir-rich cloud staying around the earth for
such a long time. The solar wind will blow it to Jupiter within a few years
at most.

> then the figure is
> about three ten millionth part per second of it.
> When converted into the
> entire surface of the earth, we get a figure of one ten trillionth per
> second per surface unit.

In other words, a trillion atoms of Deccan basalt per second per... what
surface unit???

> Therefore, this would not have produced any giant
> dust, heat, fire and smoke as a result of sulfur-dioxide, or tsunami
> effect. For this reason we do not have to attempt to find an explanation
> to the controversies discussed in the previous material.

But we do have to find an explanation for the other evidence of an impact.
For example, shocked quartz, the meteorite splinter found in the boundary
layer somewhere in the Pacific, and the _crater_(s). And we have to find an
explanation for the tsunami deposits all around the Gulf of Mexico. And for
the soot in the boundary layer.

> How could iridium trigger extinctions?
>
> As I wrote before, it was not necessarily the iridium itself, but
> rather the effect of other materials, radiation, environmental
> effects all together with the iridium.

You mean uranium fell down with the iridium? Then there would be uranium and
its decay products in the boundary layer. But they aren't there.

> Iridium itself may have played a significant
> role though, since while it is hardly oxidizable, it still does form
> compounds in other ways. (Materials in the sea, especially when taking the
> long period of time into consideration, might have dissolved iridium and
> as a result it became much more active).

Please be more specific. Suggest a specific mechanism, or this hypothesis is
untestable, therefore unscientific and must be _ignored_ by scientists.

> We can not prove iridium's damaging effect directly
> in the case of those animals that became extinct 65 million
> years ago (not even the possible indifference or resistance of
> certain animals). We only can make assumptions.

Mmm... the situation is better. We can make hypotheses. Here's how:
http://www.dinosauria.com/jdp/misc/parsimony.htm. (Please ignore the fact
that this site says "*Compsognathus primus*" instead of *Sinosauropteryx
prima*.)

> (That is iridium does participate in the natural vital processes.)

Hardly. And most importantly, the concentrations are so ridiculously low...

> We can see, therefore, that this theory does not have
> inconsistencies like the ones of the impact theory.

Well, I've disproved that. :-)