[meteorite-list] Tektite debate

From: meteorites_at_space.com <meteorites_at_meteoritecentral.com>
Date: Thu Apr 22 09:43:32 2004
Message-ID: <20010719033426.16395.cpmta_at_c000.snv.cp.net>

On Wed, 18 July 2001, "Matson, Robert" wrote:

>
> Hi Steve and Kelly (and whoever else is following this debate),
>
> Steve -- a couple of remarks about some of your arguments. My
> apologies for quoting you out of full context, but I believe
> the sections I've "snipped" stand on their own, and requoting
> two and three times tends to get tedious for readers:
>
> You wrote, "I do not confess to be a physicist or a mathematician such as
> yourself-- However-- I do see that your assumptions lack certain elements
> that are required to explain obvious facts. That is Tunguska events, and
> also
> the possibility based on the physical evidence that mega Tunguska events
> can,
> and do occur-- as the presence of the tektites attest."
>
> You're applying a bit of circular reasoning here. You've been
> saying that tektites are one of the resultant effects of a "mega
> Tunguska" event, but here you argue that tektites are the proof
&#61656; that mega Tunguska events do occur.

SRS>
No, not exactly. And I doubt that I used so strong a term as "proof."

That aside, I think that the fact that tektites exist, and are scattered the
way the appear to be over the surface of the Earth is a fair indication that
the were produced in a very violent event.

>
> While the Tunguska event was clearly impressive in terms of the
> scale of devastation it caused, physics does not allow you to
> linearly "scale-up" this event by much. Beyond a relatively
> small scaling factor (I doubt even as much as a factor of 10),
> some mass must reach the ground retaining the majority of its
> cosmic velocity. I don't see how you can avoid creating both
&#61656; an atmospheric AND a land crater.

RIGHT! Absolutely right, and I made reference to this when I
mentioned that there are at least two sites, that have what may be
large impact features-- Bosumptui (sp) _at_ 10Km? (Ivory Coast tektites)
10 km?; and Tonle Sap (elongated lake of inexplicable origin) 75 Km (?)
in the center of the Australasian tektite field. Then there is the Chesapeake
astroblembe (50 km ?)that appears to be related to the Georgia tektites

None of these craters, including Tonle Sap (which is being investigated)
are large enough to account for the tektites that they supposedly produced.

Hence, the idea that you stated above. The major event was in the air,
perhaps As a series of Tunguska events as Dr. Wasson proposed, with
some of the impactor making it to the ground to produce the craters
that we do see.

And I must point out I don't think that this is a new idea and original
yours truly.
 
>
> Unless, perhaps, the impact occurred over the ocean. I realize
> that tektites are bone dry, but water could not exist in liquid
> form at the impact point (and perhaps not even in gaseous
> form). Could the ocean floor provide the source of the tektite
> silica? If so, could large impact craters remain hidden at
> the ocean bottom, or have global surveys today been sufficiently
> thorough that none of this size could avoid discovery? (I'm
> asking -- I don't know the answer.) I'm just trying to approach
&#61656; this problem from a logic standpoint:

SRS>
You are hitting the nail on the head. Tektites are beyond a shadow
of a doubt caused by a very violent events. Someone here
on the list pointed out that the distribution of the Australasian
tektites conform the the "classic butterfly" pattern produced by
thermonuclear airbursts and this very same pattern was observed
at Tunguska itself. I recall reading the same somewhere, and if
that person still following this thread, perhaps they could come
forward with more information and sources.

The fact of the matter is that tektites are found scattered over
As much as 10% of the surface of the Earth in patterns that suggest
  violent events, but no craters of sufficient size can be found to
account for their formation.

So what conclusions can we draw from this. If the craters of
Sufficient size do not exist, the ones that appear to be associate are
 too small ????

This is a question that begs for an answer.

And the only explanation that I, and others can come up with are
mega-Tunguska events.

Now, I and others must ask, if so… how is this possible?
Can models be formulated that reflect the reality of the situation as it is
observed?

At the other extreme of this is the Chinguetti Iron. The story was bandied
  for years and scoffed at as being impossible. But a mathematician with
quite a bit of brain power found that under certain conditions such an
object could in fact make it to the ground intact without having to
vaproize on impact.

The other extreme is the question of mega Tungusaka events?

That is the question, and it in light of the tektite dilemma begs for an
answer. Can such an event be one horrendous singular meta Tunguska
event, or can it be as Dr. Wasson proposed a swarm of maximum
Tungusa events (with a crater or two being produced by masses that
Do reach the ground, as in Bosumptui, or Chesapeake Bay craters).

The strict models that Kelly and others use do not take variables such as
I have outlined previously.


>
> 1. Assume tektites are produced from earth material by impacts.
> 2. The large extent of tektite distribution fields requires
> the mass of the impacting body to be quite large.
> 3. Medium-sized comets and meteoroids can "explode" in the
> atmosphere (e.g. Tunguska) without producing a crater.
> 4. Beyond a certain mass, earth's atmosphere cannot prevent
> some material from reaching the "ground" retaining much of
> its cosmic velocity, regardless of the density or structural
> integrity of the impactor. [While Steve might initially
> disagree with this point #4, I'm hoping he'll key-in on the
&#61656; initial phrase "Beyond a certain mass".]

SRS>
Mass has a lot to do in the existing models as to how the impact, occurs
  but these models fall short in addressing the factors introduced by the
mature of the impactor. I strongly doubt that these models explain fully,
by nature of brute mass what actually happens when a comet, of a loosely
compacted nature enters the Earth's atmosphere at the highest velocity
possible, traveling in a retrograde motion respective to the Earth and
then slamming into our Earth's atmosphere at its own speed combined
with that of the Earth's

The parent body of the Leonids is a comet with an period of 34 years.
It travels in a retrograde motion to the Earth, and the meteors caused, by
it are fast, but by no means as fast as they can get if say the comet in
question had an period of say 20,000 years.

Such an object would slam into the Earth's atmosphere with enormous,
and, the angle of attack will also factor in how it can break up. I am not
sure what angle would be best of producing a mega Tunguska event. Is
it a steep angle with the 10 km comet hitting head on, or is it a grazing
strike where it is never aimed directly at the surface by would if it
stayed together pass a few miles above the surface of the Earth.

These are, taking into account structural constraints, factors that I am
referring to when I say that the models may not reflect the reality of
the situation.

Yes, such is hypothetical-- but could such indeed be fact?

Models addressing this question need to be explored. The fact that
tektites exist and are scattered the way that they do demands it.
 
But to take the stand that current models demand that mega Tunguska
events are impossible is being blindsided by convention.

The presence of tektites on our planet demand that we re-examine our
conventions and look again.

 
> 5. The mass required by point #2 exceeds the limiting mass in
&#61656; point #4. [ Okay, now Steve can object. ;-) ]

SRS>
All ready did, as in the above.

> 6. A "ground" crater must be produced at the time of impact.
> 7. The craters associated with the 4 (or is it 5?) major tektite
> strewnfields either have not all been found, or there is
> disagreement over whether the candidate craters that have
> been found are of sufficient size or of the proper age to
> match their associated tektites.
> 8. There has been insufficient time for geologic processes to
> hide evidence of land craters of the size required by point #2.
> 9. Large craters in ocean basins remain to be discovered.
> [Conjecture on my part, but considering the recentness of
> discoveries like the Yucatan and Chesapeake Bay impacts, I
> think it's a safe bet.]
> 10. One or more tektite strewnfields may be associated with
> craters in #9 that remain to be discovered. Indeed, statistics
> suggests that 3 out of 4 strewnfields should be associated
&#61656; with ocean impacts.

SRS> Possible, and quite likely.

>
> One geographical corollary that comes from #10 is that if the
> tektites of the rarest and most unusual shapes are found closest
> to the point of impact, then most of these special forms will
&#61656; have been lost to the ocean.

SRS> And as I understand it. The rarest and most unusual, as well
as the largest forms are found on land. Microtektites are found in
the ocean sediments associated with the time frame for their formation.

>
> I guess I need to hurry and post this before it becomes obsolete!
> So many long messages are being exchanged back and forth between
> Kelly and Steve that no one else has a chance to chime in before
> the emphasis of the discussion has shifted gears... --Rob
>

SRS>

Nothing like the heat of debate…. Tell you this, it is a heck of a lot better
and enlightening than discussing Ebay, meteorite prices, or marketing.

I am not an authority on this subject, but the lively and good natured
debate that has ensued bewteen me and Darryl Futrell, and Kelly Webb
has been the most challenging that I have had in an internet forum. I have
learned much and hope to learn more about the tektite enigma.

Steve Schoner.


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Received on Wed 18 Jul 2001 11:34:26 PM PDT