[meteorite-list] Largest Crater in the Sahara Desert and LDG

From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Mon Mar 6 15:47:41 2006
Message-ID: <215.1423b2a2.313df9c4_at_aol.com>

Sterling W. writes:

<<Doug, the actual language Kroeberl uses
 is that the F/B ratio of tektites "should tend
 toward 1.0." This is Professional Science
 Speak for "too complex to model exactly,
 but most of the cows ought to stampede
 in this direction...">>

Hola Sterling, I asked you where you got the moldavite value for boron. You
are now a primary source on the Internet saying that moldavites have this
content and some tektite man at some place like lpi may believe you... It is very
tedious to measure boron apparenty by spectrophotometric methods - it would
be a fair question to ask you how you got it...Slap me, call me insulting, do I
really deserve it because it sure sounded to me you might have invented the
"typical" value of Boron=30 ppm in moldavites and pass it off as a "typical"
number for moldavites because you got caught up in a roll fitting numbers to
produce a 1.0 ratio you were trumpeting - when you had no such data. If I am
wrong please forgive me enough to be on speaking terms, and if I am right, please
come clean.

Let me say I am much more comfortable with this last post you made than the
prior last off-the-wall statements about tektite formation at 34,000 degree
(you really did say this, I read all of your posting) plasma-formed tektites
miraculously being heated in microseconds to the point where first fluorine is
driven off to a theoretical "identical" level as boron, and then they diffuse out
at identical rates ignoring "petty" chemical differences.

We could start with considering that at the temperature you quoted being
reached, neither water, nor silicon dioxide the base material of tektite glass
would survive, so I think you are confusing tektites with theoretical particle
physics over a few pitchers in the Athenaeum. I mean this in the nice way, and
need to state it as it is the heart of my disagreement on the sloopy use of
the data. I am really entertained by your posts generally - you are probably my
favorite poster! But you have have mixed speculation with data here and
taken liberties to mix them and present them labeled as fact.

While Dr. Koeberl (please check the proper your spelling of your sources'
surname) may have used the word "tend" as you state above, did it occur he just
meant that the average of a few measurements was in a ballpark of 1? Let's not
turn this incredibly simple issue into a greased pig with talk of cows
stampeding and so forth. I don't need to sort it out with Dr. Koeberl as you
suggested, I think his paper was self explanatory, well done though not one of his
better ones, though it would have benefitted by someone proofreading better the
English as to not give rise to such ambiguities in interpretation. Also, as
I asked you to kindly clarify, and you did, the sample size as I asked you to
clarify was tiny - I'm not gonna let you off the hook on that yet.

 <<And you're right; he didn't analyze that
 many samples. I wish he had more data.>>

Well, let's do better here: the paper has five "tektite" samples for which
both fluorine and boron were determined.

<<He found one ivorite with a F/B ratio of
 0.40 (means more boron than fluorine).>>

Yes, he did. And you can't discount it. It was one of only five samples.
Call it an outlier if you wish. But it totally nukes your wishful
morphing-random walking diffusion plasmoid theory and imaginative mechanisms which you
presented as fact.

<<Most results were 0.8 to 1.2, which
 indeed is a 'tendency" toward 1.0,
 if you think numbers have tendencies.>>

I don't think the numbers have tendencies in the sense you used them to build
an astounding physicist view. I think numbers are cold and cruel. Let's
look at the tektite numbers in the paper excluding the Muong Nongs as the authors
suggest:
[F]/[B] ratios
Thailandite 1 1.2
Thailandite 2 1.5
Bediasite 1 0.8
Ivory C. tek. 1 1.2
Ivory C. tek. 2 0.4

Tending to 1.0? "Professional science speak" huh? No, no, no and no.
Sorry, but no. I'd go for "Settle in the ball park of 1.0", provided no one uses
Sterling's logic to shove Fluorine and Boron into one ball, and provided that
no one saying and implying that these molecules or elements coordinate
themselves to reach equal levels in time to loose their identies only to regain them
again...

Degreasing the pig, let's grab a hold of it and cut to the throat of the
issue. You originally argued that LDG's were extremely hot like tektites pointing
to this fluorine-boron "thermometer" and told us without references that the
fluorine and boron values were 7 ppm each in LDGs, arguing that this made them
comparable to heat for tektites, and that the low absolute ppm numbers (which
were lowers than most tektites, btw). You said that geochemists were behind
this, not friendly physicists, and that all of this is established protocol
for geo- and cosmo-chemists. You pointed to your theories of formation of
tektites and then said this whole thing was not hatched by you. In fact, it was.

A more careful reading of the paper, and you will find that besides the 1.0
[F]:/[B] ratio for LDG which you attributed so much significance to, there was
a second LDG studied in the table, too:
[F]ppm, [B]ppm, [F]/[B] ratio
LDG 1 7, 7, 1.0
LDG 2 8, <5, *

Well, the second sample had no ratio reported. But: it is clear that sample
2 has a ratio GREATER THAN 1.6 for [F]/[B]. How much GREATER? Maybe a lot.
Maybe a little, we don't know though. (though I could speculate <5 means 4 or
less, so we are in the 2.0 or higher index). Note aside: there was also a
second Bediasite with coincidentally equal B and F ppms as the LDG 2. So its
ratio was actually GREATER THAN 1.6 or 2.0, too.

Then there are the absolute numbers to deal with. The low value of "7" you
attributed AS FACT to the incredible heat of formation of LDG's (while you
brushed off the contradictory water content and inclusions)? Well, as you see, it
might be 7, it might be 8 or it might be 4, etc. They are all quite low,
though. Let's not read into the data more than it allows, nor look to geologists
for a better "thermometer" yet. How about asking Dr. Koeberl? Nah, let's
just read his paper to get it in writing:
"The low F and B contents in LDG and Aouelloul impact glasses are most
probably due to low contents in the precursor materials."
At no point in Dr. Koeberl's paper does he support the fantastic boron &
fluorine mechanisms you have imagined - he, like I have stated, simply says that
Fluorine will be preferentially outgassed during random diffusion. No looking
for the magic level, no going down together in unison, good grief. He seems
to be suggesting that anyone wanting to know more explanations should look to
the source rock - which is what I said in my original objection refuting your
claims about extrapolating with the "thermometer"..

No one argues that all impact glasses aren't hot, not even me. LDG's also
have a somewhat layered microstructure and the 2.0 is up into the Muong Nong
range now, for what its worth (not too toooo much, of course...) Now with that,
die bad theory! Resurrect thyself from the lab and field and not the
armchair...

It is much more palatable to me to view the approximate ratio as a very
general concept where a splashform will have a lower value than a Nuong Nong from
the SAME source material. These comparisons in the lab are hard enough for the
same event,let alone different ones - and that the measured range is 0.4 to 5
for a few tektites and impact glasses. Let me now comfortably settle back
into my armchair and congratulate everyone involved in the research efforts, as
well as the "babblers" (not my word, but I find sometimes irony them out
works!)...

Saludos, Doug
PS I'm still hoping to know the values of [F] and [B] in the LDG country
rock...maybe Norm or some other real geologist out there has them in a geology
handbook?
Received on Mon 06 Mar 2006 03:47:00 PM PST


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