[meteorite-list] Tektites-Earthites

From: Zelimir Gabelica <Z.Gabelica_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:35 2004
Message-ID: <1.5.4.32.20031024103025.00893790_at_pop.univ-mulhouse.fr>

Mark,

I believe it is well understood that tektites are of terrestrial origin
(one, probably the most widely accepted theory). My remark was more subtle.=
=20
Without having data on hand to check, I believe that a tektite is considered
as a terrestrial (silica -rich or -enriched) material ejected (by some
impactor) to the high atmosphere (stratosphere...), say several dozens of Km
high and that then they "soon" fell down on earth again, not necessarily
next to the impact site (example: Ries) in the usual well known form,
shape, morphology, composition, characterizing most of the traditional=
 tektites.
 How "high" and "how" soon? That might be the question.
=20
In other words, if this ejecta would escape the terrestrial gravity and be
sent into space for a long time (dozen, hundred, millon...years?) and then,
by chance, fall again down on earth, they could (should) be called=
 "earthites".=20
The question is: would they then have the same characteristics as our good
old usual tektites ? Some crust ? or...?=20
In any case, there is no reason that their core (perhaps also the outer rim)
does not remain "melted" as in traditional tektites.
Also: would the atmospheric friction damages have the same effect on their
characteristics in both cases ?

In the preceding post, my (provocative) question was: can our "good old
usual tektites" be considered as "METEORITES from terrestrial origin"? I
know that, following the traditional theories, they would not (necessarily)
correspond to the current definition of a meteorite. But then I naively
imagine that the distance (from earth, upon ejection) and time (spent in
space) are more accurately defined so as to discriminate between "tektites"
and these (so far hypothetical) "earthites".

Note that I would love that tektites are once considered as true
(terrestrial) meteorites. My collection would then be enriched by more than
300 "earthites" of which more than 10 unpaired...

Oh, I also agree on two other points you mentioned:
- "sedimentary earthites" should also exist and
-"barrage of posts" in view...

Best wishes,

Zelimir

At 10:29 24/10/03 +0100, you wrote:
>
>Zelmir,
>
>Indeed!, I was being ironic when I said Earthites would look like Tektites.
I think it is widely accepted that Tektites are Terrestrial! (wait for the
barrage of posts :) The fact that fused silica is found around impact
craters ought to be a blimming clue !!
>
>But also, surley there ought to be some intermediate meteorites somewhere
between Tektites and normal terrestrial rock ? (it would have to have been
big enough with the right velocity to make it back alive to earth though..
>
>Mark Ford
>
>
>
>
>
>-----Original Message-----
>From: Zelimir Gabelica [mailto:Z.Gabelica_at_uha.fr]=20
>Sent: 24 October 2003 09:29
>To: meteorite-list_at_meteoritecentral.com
>Subject: [meteorite-list] "Earthite"
>
>Mark,
>
>If your "earthite meteorite" would look like "a tektite or silica glass"
>then the tektites ARE "Earthites" !?
>
>Shows my ignorance (although I well know the different theories about the
>origin of tektites) but glad if my kidding provokes some debate among=
 experts.
>That is way is this list for. In other words, a stupid (or provocative)
>proposal is sometimes needed to get a keen answer.
>
>Cheers,
>
>Zelimir
>
>At 09:01 24/10/03 +0100, you wrote:
>>
>>
>>More to the point where are all the earth meteorites? We should be able
>>to recognize them, (one would hope!), I guess as most of the earths
>>immediate surface is soil, or sedimentary rock(s), an earthite meteorite
>>would be pretty strange do date no true 'sedimentary' meteorites have
>>been found?, I guess it would probably look like a tektite I.e silica
>>glass... or would they be just be highly shocked ordinary terrestrial
>>rocks but with a fusion crust?
>>
>>
>>Mark Ford
>
>******************************************************
>Prof. Zelimir Gabelica
>Groupe S=E9curit=E9 et Ecologie Chimiques (GSEC) - ENSCMu
>3, rue A. Werner
>F-68093 MULHOUSE Cedex, FRANCE
>Tel: +33 (0)3 89 33 68 94
>FAX: +33 (0)3 89 33 68 15
>e-Mail: Z.Gabelica_at_uha.fr
>******************************************************
>
>
>
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******************************************************
Prof. Zelimir Gabelica
Groupe S=E9curit=E9 et Ecologie Chimiques (GSEC) - ENSCMu
3, rue A. Werner
F-68093 MULHOUSE Cedex, FRANCE
Tel: +33 (0)3 89 33 68 94
FAX: +33 (0)3 89 33 68 15
e-Mail: Z.Gabelica_at_uha.fr
******************************************************
Received on Fri 24 Oct 2003 06:30:25 AM PDT