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MISSING: 9.04 kilogram Sikhote-Alin shrapnel individual   More Info


 
Tafassasset   contributed by Paladino Vincenzino, IMCA 4223   MetBul Link


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36 grams.   Achondrite-prim

TKW 115 kg. Fall not observed. Found 14 February 2000, in the Tenere desert, Niger.

From the MetBul:
The dominant lithology has a coarse grain size. It consists of olivine (poikilitically enclosed within pyroxenes in the relic chondrules), a small amount of plagioclase, 10% metal in rounded or oval-shaped grains often edged by chromite, and minor sulphides in small grains. The interchondrule matrix consists of subhedral crystals of olivine embedded in plagioclase and within anhedral crystals of chromite and phosphate that are up to 1 mm in size. Two distinct plagioclase compositions are present: An46.4Or2.2 in the matrix and An26.6Or5.2 in chondrule relics. A second lithology is finer grained and porous, without large metal grains but with fairly abundant sulphide grains.

     
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Found at the arrow (green or red) on the map below

 


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Viņales
Paul Griffin

This Month

Tracy Latimer
 7/8/2020 3:35:07 PM
I'm still pleased I have a slice in my collection.
Bernd Pauli
 7/6/2020 3:46:21 PM
T.E. Bunch once called it a metachondrite.
Stephan Kambach
 7/6/2020 2:05:54 PM
The relict chondrules are not the criterion for confirmation and reasoning for a CR classification. Primitive achondrites can generally contain relict chondrules. Above all it was important to find triple junctions / 120 * grain boundaries. The noble gas analyzes also played a role. There were and are a lot of other reasons, which ultimately also resulted from human misconduct around the time of the classification, but I do not want to mention them here anymore. To do this, one would have to ask the participants directly; perhaps these are now ready for an objective statement. For my poor understanding, the primitive achondrite is more realistic as the classifications.
Paladino vincenzino
 7/6/2020 1:52:37 PM
perhaps a partial fusion within the parent body
Paladino vincenzino
 7/6/2020 1:38:32 PM
thanks for your comments, of course one thing is sure .TAFASSASSET will never cease to surprise us
Anne Black
 7/6/2020 1:02:17 PM
Good old Tafassasset, the trouble maker. Yes I know that it has been re-classified one more time! as an achondrite. The problem with that is that thin-sections do show relict chondrules. Yes, "relict", but chondrules nethertheless. I still believe that the classification as related to CR is correct. Thank you Bernd.
John Divelbiss
 7/6/2020 11:08:49 AM
a fragment of this stuff is a truly "out of this world" looking stone! I will share pics of one...on another day. :)
Paladino vincenzino
 7/6/2020 10:28:15 AM
very mysterious meteorite, surely in the future it will reveal more secrets
Bernd Pauli
 7/6/2020 9:56:56 AM
Although, on the other hand, there is a MAPS article published in 2019 where the authors still speak of "related to CR chondrites". here is the article: ABE D. et al. (2019) Mineralogical Comparison of Northwest Africa 7317 and Tafassasset: Two Equilibrated Rocks Related to CR Chondrites (MAPS 54, 2019).
MPOD
 7/6/2020 9:14:06 AM
Thanks for pointing that out Stephan.
Stephan Kambach
 7/6/2020 7:28:28 AM
In the meteoritical bulletin see the proposed classification; also under MB 104: primitive achondrite. Tafassasset has not been CR-an for a long time already. Reclassification
 

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