[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

extinction



Gentlemen:
I am very happy because you are so active. And this is my problem, too. I
can understand your letter and I can answer fast but...in Hungarian only.
My English isn't good enough to translate promptly. My answer is late and
you are writing more and more letter. I am unable to answer each therefore
I try to give universal answers. 

1. ACCORDING IRIDIUM:

1.1.Mr Marjanovic wrote:
'"_Chemical properties:_ Iridium is the chemically most inert of all metals,
it can be attacked by no acid, but can be dissolved at 150 °C in
hydrochloric acid containing sodium chloride, also in molten sodium chloride
and [sodium] cyanide."

But:

"_Iridium compounds:_ The _iridium(IV) oxide_, IrO2, is formed in heating
iridium dust in the presence of air, it is a black, tetragonally crystalline
substance."

Ref: Bertelsmann Lexikon Chemie. Grundlagen, chemische Elemente -- 
Organische Chemie -- Grundstoffe und Verfahren, Bertelsmann Lexikon 1995, p.
228, my translation

Sounds like the Ir delivered into the air by an impact would immediately
burn down and reach the ground as its dioxide. I've done a google search on
"IrO2":
        According to http://www.finishing.com/240/86.html it isn't soluble
in water, but see below. An acid H2IrCl6 exists in any case, and is
water-soluble
http://www.arofe.army.mil/Conferences/Recent_Abstract/200th_Meeting/symposia
/f1/0829.pdf,
http://www.arofe.army.mil/Conferences/Recent_Abstract/200th_Meeting/symposia
/m1/1337.pdf;
the impact must have vaporized loads of seawater, so the presence of
chlorine atoms/ions in the fireball which also contained the iridium is
expected.
        The last of the 3,480 results I've checked out is
http://www.pse.pbf.hr/hrvatski/elementi/ir/spojevi.html. Problem is, I don't
speak Serbocroatian, just some Russian... but this page seems to describe a
reaction where Ir is oxidized to IrO2 by _potassium nitrate_ without drastic
conditions. "Chemically most inert of all metals"? Not in this respect!!!
The next line shows what happens when IrO2 is treated with hydrochloric
acid: the water-soluble acid mentioned above comes out. Further down Ir(OH)4
is mentioned; I wonder if this is water-soluble, too.'

1.2.And my answer:
 The very fine powder form (so called Ir-soot) can produce IrO2 at
atmospheric pressure and medium high temperature but it isn't found in the
nature. The common form of Ir can oxidize in pure oxigen atmosphere and
high temperature and pressure only. According this fact can use Ir in the
most sensitive part of ignition-plug of automotive systems because can
resist of air-components at that high temperature and pressure. 

The so called hydrogen-chloro-iridiumate can produce from
sodium-chloro-iridiumate what can produce from Ir and NaCl in chlor
atmosphere at high temperature. This combination isn't in the nature.

And where is potassium nitrate in the atmosphere?
 
Ir can dissolve in special and very rare circumstance and slowly in the
nature therefore it can found in elementary form. (My first diploma is
chemical engineer.) 

2. ACCORDING DECCAN BASALT FLOW:
2.1. Mr Marjanovic wrote:
'...Secondly, the Ir cannot _possibly_ have come from the Deccan traps, for 3
reasons:
- The Deccan basalts contain 0.1 ppt (zero point one parts per trillion)
iridium -- this is one of the lowest values ever measured. Ref:
James Lawrence Powell: Night Comes to the Cretaceous. Dinosaur extinction
and the transformation of modern geology, W. H. Freeman 1998
- The main phase of Deccan volcanism ended some 100,000 years before the K-T
boundary. Ref:
G. Ravizza & B. Peucker-Ehrenbrink: Chemostratigraphic evidence of Deccan
Volcanism from the Marine Osmium Isotope Record, Science 302, 1392 -- 1395
(21 November 2003). (This paper happens to confirm your idea that the Deccan
volcanism produced a greenhouse.)
- The volcanism at Deccan was effusive -- flood basalts -- and not
explosive, and therefore cannot have blasted heavy stuff like Ir high up
into the atmosphere (so that it could have fallen down all over the globe).'

2.2. My comment:
These facts can exclude originate the Ir anomaly of Deccan basalt flow. 


3. ACCORDING THE TIME OF IRIDIUM ANOMALY 

3.1. Mr McLean wrote:
'New information on this topic can be found in a paper by Zhao et al. 
titled "A possible causal relationship between extinction of 
dinosaurs and K/T iridium enrichment in the Nanxiong Basin, South 
China: evidence from dinosaur eggshells" (Palaeogeography, 
Palaeoclimatology, Palaeoecology, 2002, v. 178, pp. 1-17).

The authors indicate that iridium and other trace element buildup in 
the environment, and consequently in dinosaur tissues, likely caused 
pathological thicknesses in dinosaur eggs, and microstructural 
alterations of the eggshells. Because multiple iridium spikes were 
distributed over a temporally long Cretaceous-Tertiary duration, they 
indicate also that the source of the iridium was likely the Deccan 
Traps volcanism, and not an asteroid impact.'

3.2. My reaction:
The large impact didn't leave time for dinosaurs to produce these
pathological eggs.
 
According my theory it was enough time to cause this problem.

4. ACCORDING THE "FOSSIL ANOMALY"

4.1. Mr Bigelow wrote ( the part with > > sign came from my article):

'> > - number 4. "Within a very short period of time (minutes, hours, 
> days,
> > weeks based on the distance) a large amount of fossils should have 
> been
> > produced in
> > high density. Where are these?"


> Anything that dies within minutes of an impact is, presumably, very 
> close to
> the point of impact.  Anything close to the point of impact would be 
> pretty
> much obliterated from a fossil formation point of view.


The following 2 classic papers are required reading for anyone pondering
why there is no "big K-T boundary bonebed", caused by all of the
dinosaurs (and other critters) suddenly keeling-over in their tracks:

Signor, P. W., and J. H. Lipps. 1982. Sampling bias, gradual extinction
patterns and catastrophes in the fossil record, p. 291-296, in Silver,
L.T., and P.H. Schultz (eds.). Geological implications of impacts of
large asteroids and comets on the Earth. Geological Society of America
Special Paper 190.

Williams, M. E. 1994. Catastrophic versus noncatastrophic extinction of
the dinosaurs: Testing, falsifiability, and the burdon of proof.  Journal
of Paleontology 68: 183-190.'

4.2. My answer:

I wrote about "fossils" not only "fossils of dinosaurs" therefore Mr
Bigelow didn't answer to my question. (And I red from Signor-Lipps effect
before I wrote my articles.)

5. ACCORDING SPECIAL GROUP OF FOSSILS

5.1. Mr Habib wrote (the > signs from my article):
'> - number 5. "The referred book wittily calls the effect 'volley firing'.
> That is, the devastation would have depended neither on the age of the
> living thing nor
> on any other factor modifying the frequency of the death. In such a case,
> young individuals would have died in the same way as the old ones, the
> healthy ones, or the sick ones, etc. Have they found such unusual
> 'cemeteries'?"

Again, this is generally a problem with fossil frequencies across the board.
There must have been more babies dying than adults at all times, not just
during the K/T event, yet juveniles are rather rare.  There are various
reasons for this, some are in the archives.'

5.2. My answer:
I wrote about so special "cemetery" where can find in same place many of
young individuals, old ones, healthy ones, sick ones, etc. 

I try to answer to other letters in the next week.

Endre Simonyi