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

From: j.divelbiss_at_att.net <j.divelbiss_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:53 2004
Message-ID: <032420040655.2662.4ab5_at_att.net>

Adam,

Does this material attract to a magnet? Being an H, I suppose it does...but maybe not.

John

> 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
>
>
>
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Received on Wed 24 Mar 2004 01:55:07 AM PST