[meteorite-list] moldavite splashforms w/ artifacts. Inquiry?

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Thu Apr 22 10:14:08 2004
Message-ID: <3EAE0E80.4D8335FD_at_bhil.com>

Paul Heinrich wrote:

> On Mon, 28 Apr 2003 00:12:18 -0500
> Sterling K. Webb kelly_at_bhil.com Wrote:
>
> Mrs. Webb is mixing apples and oranges and
> putting words in my mouth that I did not
> say as I am just talking about the moldavites
> and not other types of tektites.

Speaking of mixing apples and oranges,
I do not know on what basis you decided I was a "Mrs."
but I am of the "Mr." classification.
Maybe the middle name "kelly" which I got
to preserve the family name of my mother
who was orphaned in 1916. For decades, I was the
only "kelly" (as a first name) anyone had ever met,
but then a few million "kelly's" were generated
in the past 25 years. Nevertheless, the correct
classification is "Mr." The morphology
is distinctive and definitive.

>
>
> Many of the other tektites, which she mentions,
> I would well agree retain a large degree of
> their surface morphology and that I don't
> dispute. I am ++not++ arguing that the surface
> morphology of all tektites, as Mrs. Webb
> incorrectly implies, is the result of etching.
> The aerodynamic forms of australite buttons
> clearly demonstrate. Again, my discussion
> just applies to moldavites.++
>
> Mrs. Webb stated:
>
> >Frankly, I feel that the popularity of
> >the "differential chemical etching"
> >theory is due to its ability to dismiss
> >in a single phrase a complex morphology
> >that defies easy explanation and which
> >has been inadequately studied.

Remember, I said I wished the more informed would jump in
here, and Norm Lehrman (definitely the more informed) did:

"However, Besednice hedgehogs demonstrate the converse. It
cannot be a
coincidence that the famous ornamentation in this case is found
in one tiny
area a few hundred feet square, and even within that area, only
the
specimens at the water-table show the extreme etching.
Moldavites found
even a meter or so higher in the alluvial profile are not so
etched."

So, I stand corrected. I was dead wrong. But I'm still a "Mr."

>
> This is not true, the popularity of the
> chemicaletching explanation is the result
> of the fact that the complex forms that
> moldavites exhibit, and I am just talking
> about the moldavites, is the type of complex
> morphology that results when materials
> corroded by chemical etching.
>
> >While aerodynamic ablation is "probably"
> >the answer, no one has undertaken the
> >monumental job of classifying and
> >thoroughly explaining the great
> >variety of features that are to be
> >found.
>
> The fact that people have been able to
> explain the morphology of australite
> buttons using aerodynamics and nobody
> has yet been able to explain the
> complex form of moldavites with
> aerodynamics suggests to me that it
> has proven useless as explanation for
> the formation of moldavites. (Again
> I am just discussing moldavites,
> **not*** other forms of tektites.)
> In contrast, the form that moldavites
> have is the classic shapes geologist
> often observe in the corrosion of many
> types of materials.

The implication that only the australite button form
can be explained by aerodynamics (at least I think that
you're implying that) is misleading. Baker, in a series
of papers written in the 1940's, clearly explained the
aerodynamic origin of the common tektite forms ("spheres,
discs, ellipsoids (ovals), lenses, cylinders, rods,
dumb-bells,"). It would appear that the "leaf" alone
is a product of chemical weathering. It is worth noting
that attempts to duplicate chemical etching on clean "unetched"
tektites specimins have never yielded results even vaguely
like the surface features on common tektites (non-leaf).

> >Both the frequency of symmetry and the
> >common orientation of features on Besednice
> >"leaf" moldavites argue against "corrosion"
> >as the sculpting force.
>
> This is not true. This just means that
> there was symmetry to the internal structure
> of the original moldavite. If the internal
> structure of the etched moldavite is
> symmetrical, than the resulting etched form
> will be symmetrical. This in no way proves
> that the original form of a Besednice was
> "leaf" shaped. The common orientation in the
> moldavites just means that they have a common
> internal structure, which would corrode to
> produce a common orientation.
>
> If the Besednice were originally "leaf"
> shaped how did they survived intact being
> transported in fluvial systems and then
> deposited in the sands that they are
> found? The delicate "leaf" shaped forms
> could only have formed by corrosion once
> they had come to rest and been encased
> in the fluvial sands that they occur.
> Otherwise, they would had been completely
> been broken before being deposited with
> the fluvial sand that they are found in.
>
> There are other shapes, e.g., spheres, discs,
> ellipsoids (ovals), lenses, cylinders, rods,
> dumb-bells, and so forth which reflect the
> original, although with corroded surfaces,
> form of some moldavites. As far as the
> "leaf" shaped forms, geologists, with very
> good reason, would find the aerodynamic
> explanation extremely implausible.

True. The original forms of moldavites are probably
pretty much the same as the most common forms of the
indochinites ("spheres, discs, ellipsoids (ovals),
lenses, cylinders, rods, dumb-bells,"). In fact, I have
a neat little exhibit in my collection. I have a moldavite
"blade" form (broken off fore and aft) next to an indochinite
"blade" form. They have the same dimensions, the same curvature
of the "blade." the exact same surface sculpture (yes, exactly
the same!!) They are, however unlikely, exact twins, except
for the fact that one is green and one is black. Obviously,
whatever produces the forms and the surface sculpture is a
definable and constant process (if we could only unravel it).

> >Moreover, they are found in complete
> >range of forms from completely undamaged
> >with every little "finger" intact to
> >progressively less and less elaborate
> >forms whose reduction is mechanical
> >(breakage), not chemical.
>
> It just means that there has mechanical
> breakage after the etching of moldavite
> has occurred. Reworking of the moldavite
> deposits after they have been corroded
> can easily account for this breakage.
>
> > If chemical etching were the formative
> >agent, there would be intermediately
> >"etched" forms, and there are not.
> >There would be pieces only partially
> >"etched", and there are not. There is
> >no evidence of a range of chemical
> >activity, only of a range of mechanical
> >damage.
>
> This is not true. All of this means is that
> the deposits containing these moldavites have
> been subject to either the degree of
> weathering, diagenesis, and some combination
> of the two. As a result, any moldavite found
> in these deposits will exhibit the same degree
> of intense corrosion to the extent that
> intermediate forms and fresh moldavites simply
> don't exist. These moldavites are about 15 million
> years old and occur very porous sands that would
> have allowed intense digenatic corrosion of them.
> Under these circumstances, it is would quite
> remarkable and quite unexpected that they
> haven't been badly corroded. The lack of
> intermediate forms proves nothing about the
> origin of "leaf" shaped moldavites.
>
> Yours,
>
> Paul
> Baton Rouge, LA

Clearly, the leaf forms are unique, and from what
Norm says, only found in one precise location and
nowhere else. If I had known that, I wouldn't have
put my foot so far down my throat. Ignorance is
not bliss, but only leads to a taste of shoelaces!

Still, a lot of other moldavites look aerodynamically
shaped to me. Look at Plate 42 of Heinen's book (OK,
Guy, I plugged it twice.)


(Still a "Mr.")
Sterling K. Webb
Received on Tue 29 Apr 2003 01:32:50 AM PDT