[meteorite-list] NEW Ungrouped Achondrite - NWA 5297

From: Greg Hupe <gmhupe_at_meteoritecentral.com>
Date: Thu, 25 Feb 2010 14:28:47 -0500
Message-ID: <081C004A3756454BBABC752B6F25A59C_at_Gregor>

Dear List Members,

I would like to announce a new Ungrouped Achondrite, NWA 5297.

NWA 5297 is an Ungrouped Achondrite that was found in Morocco in early 2008.
A total of nine small dark stones were collected with a combined Total Known
Weight of just 130 grams. NWA 5297 does not fit in any of the known
classification types, making it a very unusual meteorite.



Image of 12.9g main mass:

http://www.lunarrock.com/nwa5297/nwa5297e.jpg



Image of 2.9g complete slice with large metal grain:

http://www.lunarrock.com/nwa5297/nwa5297f.jpg



Classification submitted to the Meteoritical Bulletin for NWA 5297:

Northwest Africa 5297

Morocco

Find: March 2008

Achondrite (ungrouped)

History: Found near Alargoug, Morocco in March 2008 and purchased in June
2008 by Greg Hup? from a Moroccan dealer.

Physical characteristics: A total of nine dark stones with visible metal and
a combined weight of 130 g.

Petrography: (A. Irving and S. Kuehner, UWS) This specimen has a
poikiloblastic metamorphic texture with no chondrules and contains
relatively abundant (~10 vol. %) Ni-rich metal. The major phases are
olivine, orthopyroxene, taenite and very sodic plagioclase with minor
Ni-bearing troilite.

Geochemistry: Olivine (Fa28.6, FeO/MnO = 54.4), plagioclase
(Ab86.2An9.1Or4.7), taenite (~10 wt.% Ni). Oxygen Isotopes (D. Rumble,
CIW): replicate analyses of acid-washed silicate material by laser
fluorination gave, respectively: d18O = 4.830, 5.032; d17O = 3.711, 3.818;
D17O = 1.171, 1.171 per mil.

Classification: Achondrite (ungrouped). This specimen is a metachondrite
with an oxygen isotopic composition like those of LL chondrites; however, it
contains too much metal to be regarded as a product of metamorphism of
typical LL chondrites, and the olivine composition is outside the range for
equilibrated LL chondrites.

Specimens: A total of 20 g of sample and one polished thin section are on
deposit at UWS. The main mass is held by Mr. Greg Hup? (GHup?).

Enjoy!

Best regards,
Greg

====================
Greg Hupe
The Hupe Collection
NaturesVault (eBay)
gmhupe at htn.net
www.LunarRock.com
IMCA 3163
====================
Click here for my current eBay auctions:
http://search.ebay.com/_W0QQsassZnaturesvault
Received on Thu 25 Feb 2010 02:28:47 PM PST