[meteorite-list] Back to meteorites.. reheated rims

From: Martin Altmann <altmann_at_meteoritecentral.com>
Date: Mon Aug 28 15:33:16 2006
Message-ID: <013601c6cad8$c99d8c50$4f41fea9_at_name86d88d87e2>

Hi Bernd, List,

I fully support Bernd's words
and those, who don't know him from the list for a longer time,
have to be told, that such a kind of conversation is a true abhorrence for
him and such outbursts happen so often to him like the outburst of a
naked-eye-visible supernova in a neighbour galaxy.

I had my own experiences with that Chicago person, which were by far more
unsavoury than an incorrect ebay-description, so that for the first and only
time in 25 years of collecting I decided not to buy nor to sell to a person
anymore. No further comment necessary, only, that I won't waste my time any
more on this person and I think, Bernd, you also may save your words. It is
lost time.

Now back to meteorites, just for fun Chaldni's Heirs loaded up two nice
examples of reheated rims in fresh fallen iron meteorites.

The first two pics show two halves of a small Sikhote-Alin-hexahedrite:

www.meteoritenhaus.de/img/reheated1a.jpg

www.meteoritenhaus.de/img/reheated1b.jpg

I say hexahedrite, because during the fragmentions in air, pieces broke off
along the crystal boundaries and as Sikhote-Alin is a coarsest octahedrite,
one can find with a little luck among the smaller individuals pieces
which entirely consist of one single kamacite.
Etched they will show no different fields or bars, but Neumann lines - in
our example in three different orientations.
Just like a hexahedrite and would have found from that fall only our small
sample, Sikhote-Alin would have been classified as hexahedrite :-)
The inclusion is schreibersite.

The second examples are taken from slices of a true hexahedrite, of
Boguslavka, which felt in 1916.

www.meteoritenhaus.de/img/reheated2.jpg

www.meteoritenhaus.de/img/reheated3.jpg

Again you'll see a lot of Neumann lines.

Now! Note the sharply stepped rim all along the outer edges, which looks so
granular, note also how slim the rim is - only 1-2mm.

The rim is the outer zone of the pieces, where the iron got really hot
during the flight through the atmosphere.
It got there so hot, that it lost its original structure and recrystallized.

The material only a bit deeper, didn't reached such high temperatures.

So from this examples, we can learn, that meteorites during flight aren't
melting to a noteworthy extend, but only very superficially. The material
only a few mm under the rind, stays quite unafflicted from the heat.
Most of the material of a meteorid intruding the atmosphere will be
vaporized directly without getting liquid (so called "sublimation").
That phase of flight, where the meteorid is slowed down enough, but also
fast enough, that the surface can melt, is very short and additionally the
air is cooling it.
Irons are a better conductor of heat than stone meteorites.
At stone meteorites the fusion crust typically isn't thicker as paper or a
finger nail.

So whenever you'll find a chunk in the field, which looks molten, flown or
even bubbly - then it is no meteorite.

On the other hand, if you will find such a reheated or recrystallized rim on
a cut surface of an iron meteorite, which wasn't observed to fall,
you can assume, that it resided for not a long time here on Earth,
as older irons will have lost there outer layers by weathering;
and e.g. you never will find such a rim in a Gibeon, a Campo del Cielo or in
a Muonionalusta.

End of tutorial, applause.
That's more fun than to discuss about foul apples!

Chladni's Heirs

Andreas Gren
Martin Altmann
Stefan Ralew

 


-----Urspr?ngliche Nachricht-----
Von: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com] Im Auftrag von
bernd.pauli_at_paulinet.de
Gesendet: Montag, 28. August 2006 19:51
An: Meteorite-list_at_meteoritecentral.com
Betreff: Re: [meteorite-list] open messaging

"In my opinion, you owe us (not to mention Steve Arnold) an apology."

Absolutely ridiculous!


Hello List,

Steve wrote:

" ... I have blocked this persons email so I will never see it"

Would you please also block my emails! Thank you! (<= these are
two little words that are definitely missing in your vocabulary)

Someone sent me these lines when I mentioned Steve's inability
or maybe unwillingness (?) to say "thank you":

"The fact that Steve can't say thank you just makes us the fools
for helping him repeatedly. Evidently he never learned to be gracious."

How right this list member was but I continued to make myself a fool
and again answered questions he asked the list. What a fool (I am;-)

Steve wrote:

"I have stopped along ago mudsling opun this list".

But when you did (not so very long ago), it was so mean and
offensive. It was so dirty and offensive that I wrote to a
list member:

"I won't return as long as ... keeps on provoking flame tirades against
other list members while calling them 'ass wipes' in private mails".

Oh, and Steve's sincerity and honesty is just too cool. While he kept
telling
the List how happy he was about the Bob Haag pieces he had acquired in
Tucson, so very happy he would never ever part with them, I was told by
a list member who was there in Tucson at that time:

"No need to sigh about W... Steve, in spite of his comments, he sold two of
his four Haag specimens before he ever left Tucson. So now with this auction
it will be three out of four. WYSI(NOT)WYG on the list."

Steve wrote: "Ok *d a v y* ,I think it would be a great thread to start"

"Davy", ... is this a typo??? His name is Dave Carothers, if you please. You
told me in a private mail that your name was Steve Arnold and NOT Chicago
Steve!

Well, when we had a similar uproar on this List, Steve was really lucky
because
one of our most prominent and prolific list members wanted to chime in and
tell
the List what had gone wrong in his dealings with Mr. "Why are you always
picking on me". He asked me, he hesitated and thought it best to leave
things as
they were ... status quo ... no, not the rock group :-)

.. and as for "I have stopped along ago mudsling opun this list". How long
ago?
Let me tell you how long ("short" would be the proper word here) ... how
about
April 2005.

Mr. Barford (if he wishes) may go to our List archives and find out for
himself. He'll find more than he may be inclined to read. Some examples:

1. JKGwilliam's post dated Mon Apr 11, 2005
2. My post dated Tue Apr 05, 2005
3. etc., etc., etc., etc., etc., ...

Well, time to turn to more rewarding things now.

Thank you, Dave Carothers, for these words:

"I'm sorry, but if anyone thinks that perpetrating misrepresentations and
falsehoods ... "PETTY BULL****" ...then WE as a community have
REAL problems".

Thank you, Ron Bude, for these comments:

"I would prefer not to be subjected to ... his apparent bendings of the
rules"

Best,

Bernd

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Received on Mon 28 Aug 2006 03:33:05 PM PDT