[meteorite-list] NWA 3099 (L/LL3) and why not 3.X ???

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From: Adam Hupe <adamhupe_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:47 2004
Message-ID: <019501c405fe$fe7db5e0$62f61018_at_attbi.com>

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Dear John and List members,

This is a good question that is not easy to answer. In some cases the =
petrologic subtype can not be determined to any degree of accuracy =
because shock has made it impossible to distinguish thus a 3 designation =
instead of a 3.X . Shock and Metamorphism are two different things so =
you could have a highly shocked piece that you can hardly see the =
chondrules and yet it could still be a 3.0.=20

Another problem is that there are several methods in use to determine =
low petrologic types that not all scientists agree on. Yet, another =
method has been published and will be shared at the Lunar and Planetary =
conference by Dr. Grossman. This method looks promising because it does =
not depend on the Sears TL testing apparatus from which I understand can =
not distinguish between a 3.0 and a 3.1 and weathering can skew the =
results. If the new proposed method gains acceptance than it will be a =
lot easier to determine low petrologic subtypes. Although time =
consuming It will allow laboratories to use a microprobe instead of =
other methods which in most cases require the specimen to be sent out. =
I hope Dr. Grossman's method gains acceptance as the standard as it will =
make it a lot simpler to determine 3.X subtypes.

Hope this helps and is expressed accurately,

Adam

  From: j.divelbiss_at_att.net=20
  To: Jeff Kuyken=20
  Cc: Meteorite List=20
  Sent: Tuesday, March 09, 2004 4:43 AM
  Subject: Re: [meteorite-list] NWA 3099 (L/LL3) and why not 3.X ???

  Jeff, Bernd and others:

  Great stuff guys, especially the pictures of these great =
unequilibrated stones. Will we ever=20
  understand how these anomalies ever happened...probably not. But it is =
sure is worth trying.

  Questions: I've often wondered why some of these stones are not =
evaluated further to determine=20
  the level of feldspar change/metamorphism that grades this level of =
change from the original=20
  material. Instead of simply stating it is an LL3...the grading goes =
further to say it LL3.2,=20
  LL3.5, etc. If I remember right it is a measurement of the feldspar =
glass illuminescence.=20

  1. How/who decides when to this evaluation?

  2. Is it really just a matter of available equipment in many =
cases...the facility may not=20
  have the ability to do the test...so meteorites out of those =
institutions are never beyond LL3.

  3. Is it a cost issue for doing the test?? Seems to me that LL3's =
are cheaper to buy than say LL3.5 or lower...yet I've looked at plenty =
of awesome LL3's that rival some the others with the
  extra desingation or test.

  Maybe of the dealers that have stones evaluated can tell us why this =
test is done or not.=20
  I'd like to see it done more often with beauties like NWA 3099, and =
NWA 1933. Why not is my question.

  John

  =20

-------------------------------------------------------------------------=
-----

  G'day all,

  For those of you who purchased NWA 3099 or are just interested, I =
spoke with Bernd over the past couple of weeks regarding this =
particularly remarkable meteorite. Bernd had some interesting things to =
say it which are posted at the end of the page here:

  http://www.meteoritesaustralia.com/features/nwa3099.html

  Cheers,

  Jeff Kuyken
  I.M.C.A. #3085
  www.meteorites.com.au
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<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2800.1106" name=3DGENERATOR></HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Dear John and List =
members,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>This is a good question that is not =
easy to=20
answer.  In some cases the petrologic subtype can not be determined =
to any=20
degree of accuracy because shock has made it impossible to distinguish =
thus a 3=20
designation instead of a 3.X .  Shock and Metamorphism are two =
different=20
things so you could have a highly shocked piece that you can hardly see =
the=20
chondrules and yet it could still be a 3.0. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Another problem is that there are =
several=20
methods in use to determine low petrologic types that not all scientists =
agree=20
on.  Yet, a</FONT><FONT face=3DArial size=3D2>nother method has =
been published=20
and will be shared at the Lunar and Planetary conference by Dr. =
Grossman. =20
This method looks promising because it does not depend on the Sears TL=20
testing apparatus from which I understand can not distinguish =
between=20
a 3.0 and a 3.1 and weathering can skew the results.  If the =
new=20
proposed method gains acceptance than it will be a lot easier to =
determine=20
low petrologic subtypes.  Although time consuming It =
will allow=20
laboratories to use a microprobe instead of other methods which in most=20
cases require the specimen to be sent out.  I hope Dr. =
Grossman's=20
method gains acceptance as the standard as it will make it a lot simpler =
to=20
determine 3.X subtypes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Hope this helps and is expressed=20
accurately,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Adam</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A title=3Dj.divelbiss_at_att.net=20
  href=3D"mailto:j.divelbiss_at_att.net">j.divelbiss@att.net</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Djeff_at_meteoritesaustralia.com=20
  href=3D"mailto:jeff_at_meteoritesaustralia.com">Jeff Kuyken</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Cc:</B> <A=20
  title=3Dmeteorite-list_at_meteoritecentral.com=20
  href=3D"mailto:meteorite-list_at_meteoritecentral.com">Meteorite List</A> =
</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, March 09, 2004 =
4:43=20
  AM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [meteorite-list] =
NWA 3099=20
  (L/LL3) and why not 3.X ???</DIV>
  <DIV><BR></DIV>Jeff, Bernd and others:<BR><BR>Great stuff guys, =
especially the=20
  pictures of these great unequilibrated stones. Will we ever =
<BR>understand how=20
  these anomalies ever happened...probably not. But it is sure is worth=20
  trying.<BR><BR>Questions:  I've often wondered why some of these =
stones=20
  are not evaluated further to determine <BR>the level of feldspar=20
  change/metamorphism that grades this level of change from the original =

  <BR>material. Instead of simply stating it is an LL3...the grading =
goes=20
  further to say it LL3.2, <BR>LL3.5, etc. If I remember right it is a=20
  measurement of the feldspar glass illuminescence. <BR><BR>1.  =
How/who=20
  decides when to this evaluation?<BR><BR>2.  Is it really just a =
matter of=20
  available equipment in many cases...the facility may not <BR>have the =
ability=20
  to do the test...so meteorites out of those institutions are never =
beyond=20
  LL3.<BR><BR>3.  Is it a cost issue for doing the test??  =
Seems to me=20
  that LL3's are cheaper to buy than say LL3.5 or lower...yet I've =
looked at=20
  plenty of awesome LL3's that rival some the others with the<BR>extra=20
  desingation or test.<BR><BR>Maybe of the dealers that have stones =
evaluated=20
  can tell us why this test is done or not. <BR>I'd like to see it done =
more=20
  often with beauties like NWA 3099, and NWA 1933. Why not is my=20
  question.<BR><BR><BR>John<BR><BR> <BR><BR><BR><BR><BR><BR>
  <P>
  <HR>

  <P></P>
  <META content=3D"MSHTML 6.00.2600.0" name=3DGENERATOR>
  <STYLE></STYLE>

  <DIV><FONT size=3D2>G'day all,</FONT></DIV>
  <DIV><FONT size=3D2></FONT> </DIV>
  <DIV><FONT size=3D2>For those of you who purchased NWA 3099 or are =
just=20
  interested, I spoke with Bernd over the past couple of weeks regarding =
this=20
  particularly remarkable meteorite. Bernd had some interesting =
things to=20
  say it which are posted at the end of the page here:</FONT></DIV>
  <DIV><FONT size=3D2></FONT> </DIV>
  <DIV><FONT size=3D2><A=20
  =
href=3D"http://www.meteoritesaustralia.com/features/nwa3099.html">http://=
www.meteoritesaustralia.com/features/nwa3099.html</A></FONT></DIV>
  <DIV><FONT size=3D2></FONT> </DIV>
  <DIV><FONT size=3D2>Cheers,</FONT></DIV>
  <DIV><FONT size=3D2></FONT> </DIV>
  <DIV><FONT size=3D2>Jeff Kuyken<BR>I.M.C.A. #3085<BR><A=20
  =
href=3D"http://www.meteorites.com.au">www.meteorites.com.au</A></FONT></D=
IV></BLOCKQUOTE></BODY></HTML>

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Received on Tue 09 Mar 2004 12:50:21 PM PST

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