Hi Norm,
Running a little slow in my emails, thanks for the (much earlier) reply
and nice to see you're still in touch...
Best wishes,
Doug
-----Original Message-----
From: Norm Lehrman <[EMAIL PROTECTED]>
To: Michael Gilmer <[EMAIL PROTECTED]>;
[email protected]
Sent: Fri, 4 Apr 2008 9:16 pm
Subject: Re: [meteorite-list] Atmospheric ablation marks on Tektites?
Mike,
I'm not aware of any LDG that retains preserved
external primary skin, so we don't even know what
morphology or skin LDG may have once had. What you
see now is mostly the result of desert sand-blasting
by saltating sand grains. It can look "oriented", and
indeed it is, but with respect to prevailing surface
winds, not atmospheric re-entry. Many pieces of LDG
can properly be termed "ventifacts".
The australasians, and in particular, the australites
certainly do have all sorts of thermal ablasian
features, and when it comes to orientation, flanged
buttons exceed the perfection of any meteorite. This
is "orientation" exactly as we intend the word in
meteoritics.
With tektite discussions, one answer rarely fits
all---
Cheers,
Norm
(of http://tektitesource.com , temporarily on hold
while we are stationed in Tanzania for a few years).
--- Michael Gilmer <[EMAIL PROTECTED]> wrote:
Hi Group!
While reading through another Meteorite-related
message board on the WWW, I ran across a statement
by
an IMCA member that puzzles me somewhat. A
discussion
about Libyan Desert Glass was ongoing, and we were
sharing photos of our LDG specimens. (and I showed
off my new 9+ gram piece of dark-veined glass from
Michael Farmer - thanks Mike!)
So the guy says :
"This is one of my favorites and is fully oriented
with regmaglypts (yes, tektite impactites can have
atmospheric ablation patterns too)."
Ok, here is my confusion - I was under the
impression
that tektites were formed on impact - on Earth. So,
doesn't this mean they cannot have atmospheric
ablation patterns? Assuming the tektite never
passed
through the atmosphere, I don't see how this is
possible.
I have seen tektites with features that resemble
regmaglypts and orientation, but this is just chance
occurence, right?
Or do I need to be schooled here?
Thanks in advance!
MikeG
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