[meteorite-list] Ad Weekly Rare Material (Pseudotachylite)

From: Adam Hupe <adamhupe_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:53 2004
Message-ID: <04f601c41156$3f34c8a0$ad971018_at_attbi.com>

Dear List Members,

We would like to introduce NWA 2058 an extremely odd meteorite called a
plain "H" with no subclass. It is also known in the scientific circles as a
Psuedotachylite. Through a great deal of study NAU and the UW determined
this Psuedotachylite originated from the H chondrite parent body. It was
not thought of as being a meteorite at first because it looks completely
different than anything that had been seen before. Some may ask, How come
no metamorphic subclass? It is the most shocked chondrite yet discovered
with no chondritic features that can be measured for metamorphism meaning no
metamorphic subclass can be assigned. Another problem was what to call it,
an achondrite from a chondritic parent body or simply an H with the
qualifier Psuedotachylite or melt rock. This unique material has caused a
stir in the scientific community with laboratories requesting samples which
will make this a very well studied meteorite.

Here is a brief description of this one-of-a-kind meteorite:

NWA 2058 is an H (Pseudotachylite), Fa 17.1-18.4, S6 plus, W2/3 chondrite
found in Northwest Africa 2001. This unique meteorite cannot be subclassed
because of extreme mylonitization. Mylonitization is fusion of crushed rock
under high temperature by frictional heating. In other words, this
meteorite was formed by a hypervelocity impact on the surface of an asteroid
and cooled within milliseconds as it was ejected out into space. During the
impact event it was crushed and sheared simultaneously creating subparallel
veins in the direction of the material flow connecting elongated
metal-sulfide nodules, talk about interesting! Relic grains show evidence
of high strain rates, partially granulated clasts with undulatory
extinction, in contrast to shock features. The matrix consists mostly of
recrystallized olivine. The round objects are not chondrules but are impact
melted and quenched metal sulfide. Five stones with unusually smooth fusion
crusts were found adding up to 80 grams TKW. So far 17.1 grams has been
provided to science and a great deal was lost to cutting and polishing
leaving very little for collectors. Since this unusual meteorite is still
currently under study and other laboratories are requesting samples we plan
on preserving a good portion in our collection for future studies.

I brought up that there are Hs listed with no subtype and was told this is
not the same situation as with this special meteorite. The reason for the
others is simply incomplete information. In some cases there was not enough
material to subclassify and in other cases the classifications were never
completed. In yet other cases the material was lost through time. The
classification on this unique meteorite is complete making it the only plain
H that has been fully classified with supporting data.

Since we have no idea what something like this is worth we will let the
market decide by starting over a dozen prepared specimens out at just 99
cents and see where they end up. Hopefully, the proceeds will be enough to
offset lab fees we incurred during the study of this material. This new
meteorite is so dark that is very difficult to photograph the features. I
will try to take some photomicrographs with a digital microscope in the next
few days. To see this new meteorite and over 100 interesting auctions check
out the ebay link below:

http://members.ebay.com/aboutme/meteoritelab/

Thank you for looking and if you are bidding, good luck.

Adam and Greg Hupe
The Hupe Collection
Team LunarRock
IMCA 2185
Received on Tue 23 Mar 2004 11:12:38 PM PST